IPAC2016 - List of Keywords (electron)

Paper	Title	Other Keywords	Page
MOXAA01	International Linear Collider, Latest Status towards Realization	collider, linear-collider, superconducting-RF, cryomodule	1
	S. Komamiya ICEPP, Tokyo, Japan
	This presentation describes the International Linear Collider (ILC), an e⁺ and e^- collider based on the superconducting linear accelerator with a center of mass energy of 500 GeV in the first stage, upgradeable to 1 TeV. According to the statement of the Science Council of Japan, MEXT (Ministry of Education, Science, and Sports) and the Japanese government have investigated the feasibility of the ILC project, not only from the scientific view, but also the political, economical, and sociological points of view. The latest status of the project will be presented.
	Slides MOXAA01 [12.564 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOXAA01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOYBA01	Limits and Possibilities of Laser Wakefield Accelerators	laser, plasma, coupling, focusing	16
	W. Leemans LBNL, Berkeley, California, USA
	This presentation provides an outlook into the future of laser-driven plasma wakefield accelerators. What has been achieved, what more is possible and what are the limits.
	Slides MOYBA01 [43.465 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOYBA01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOOCA03	Thyratron Replacement	operation, klystron, network, linear-collider	45
	I. Roth, M.P.J. Gaudreau, M.K. Kempkes Diversified Technologies, Inc., Bedford, Massachusetts, USA
	Funding: Work supported by DOE under contract DE-SC0011292 Semiconductor thyristors have long been used as a replacement for thyratrons in low power or long pulse RF systems. To date, however, such thyristor assemblies have not demonstrated the reliability needed for installation in short pulse, high peak power RF stations used with many pulsed electron accelerators. The fast rising current in a thyristor tends to be carried in a small region, rather than across the whole device, and this localized current concentration can cause a short circuit failure. An alternate solid-state device, the insulated-gate bipolar transistor (IGBT), can readily operate at the speed needed for the accelerator, but commercial IGBTs cannot handle the voltage and current required. It is, however, possible to assemble these devices in arrays to reach the required performance levels without sacrificing their inherent speed. Diversified Technologies, Inc. (DTI) has patented and refined the technology required to build these arrays of series-parallel connected switches. DTI is currently developing an affordable, reliable, form-fit-function replacement for the klystron modulator thyratrons at SLAC capable of pulsing at 360 kV, 420 A, 6 μs, and 120 Hz.
	Slides MOOCA03 [2.636 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOOCA03
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB003	Comparison of Coherent Smith-Purcell Radiation and Coherent Transition Radiation	radiation, laser, free-electron-laser, simulation	72
	V. Khodnevych, N. Delerue LAL, Orsay, France O.A. Bezshyyko, V. Khodnevych National Taras Shevchenko University of Kyiv, The Faculty of Physics, Kyiv, Ukraine
	Funding: The authors are grateful for the funding received from the French ANR (contract ANR-12-JS05-0003-01) and the IDEATE International Associated Laboratory (LIA) between France and Ukraine. Smith-Purcell radiation and Transition Radiation are two radiative phenomenon that occur in charged particles accelerators. For both the emission can be significantly enhanced with sufficiently short pulses and both can be used to measure the form factor of the pulse. We compare the yield of these phenomenon in different configurations and look at their application as bunch length monitors, including background filtering and rejection. We apply these calculations to the specific case of the CLIO Free Electron laser.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB003
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB004	Comparison of the Smith-purcell Radiation Yield for Different Models	radiation, simulation, experiment, detector	75
	M.S. Malovytsia, N. Delerue LAL, Orsay, France M.S. Malovytsia KhNU, Kharkov, Ukraine
	Funding: The authors are grateful for the funding received from the French ANR (contract ANR-12-JS05-0003-01) and the IDEATE International Associated Laboratory (LIA) France-Ukraine. Smith-Purcell radiation is used in several applications including the measurement of the longitudinal profile of electron bunches. A correct reconstruction of such profile requires a good understanding of the underlying model. We have compared the leading models of Smith-Purcell radiation and shown that they are in agreement within the experimental errors.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB004
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB005	Study of Short Bunches at the Free Electron Laser CLIO	radiation, cavity, gun, simulation	78
	V. Khodnevych, N. Delerue, S. Jenzer LAL, Orsay, France J.P. Berthet, F. Glotin, J.-M. Ortega, R. Prazeres CLIO/ELISE/LCP, Orsay, France V. Khodnevych National Taras Shevchenko University of Kyiv, The Faculty of Physics, Kyiv, Ukraine
	Funding: The authors are grateful for the funding received from the French ANR (contract ANR-12-JS05-0003-01). CLIO is a Free Electron Laser based on a thermionic electron gun. In its normal operating mode it delivers electron 8 pulses but studies are ongoing to shorten the pulses to about 1 ps. We report on simulations showing how the pulse can be shortened and the expected signal yield from several bunch length diagnostics (Coherent Transition Radiation, Coherent Smith Purcell Radiation).
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB005
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB007	Diamond Sensor Resolution in Simultaneous Detection of 1,2,3 Electrons at the PHIL Photoinjector Facility at LAL	detector, experiment, simulation, target	84
	V. Kubytskyi, P. Bambade, S. Barsuk LAL, Orsay, France O.A. Bezshyyko, V. Krylov, V. Rodin National Taras Shevchenko University of Kyiv, The Faculty of Physics, Kyiv, Ukraine
	In this paper, we present experimental and numerical studies of the signals from the Poisson-like distributions resulting from electrons incident on a diamond sensor placed near the exit of the PHIL photoinjector facility at LAL. The experiments were performed at the newly commissioned Low Energy Electron TECHnology (LEETECH) platform at PHIL. Bunches of 10x9 electrons are first generated and accelerated to 3.5 MeV by PHIL. The electrons are then filtered in LEETECH by a system of collimators, using a dipole magnet for momentum selection. The diamond sensor is located immediately after the output collimator to collect electrons in the range 2.5-3 MeV. We show that with standard scCVD diamonds of 500 micrometers thickness, the energy losses from the first three MIP (minimum ionizing particle) electrons are clearly resolved. We did not observe distinguishable peaks in cases when a significant fraction of the incident electrons had energies below a MIP. The described technique can be used as complementary approach for calibration of diamond detectors as well as to diagnose and help control accelerated beams in a regime down to a few particles.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB007
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB009	Electron Beam Probe for the Bunch Length Measurements at BERLinPro	diagnostics, simulation, gun, operation	92
	D. Malyutin, A.N. Matveenko HZB, Berlin, Germany
	For the successful operation of various accelerator facilities a detailed bunch characterization is required. A complete description can be achieved using various diagnostic systems installed along an accelerator beamline. Ideally the diagnostic should be able to measure parameters of a single bunch in a non-destructive manner. For bunch length measurements this results in a complicated task especially for bunch duration below 1 ps. One of the possible solutions is a diagnostic based on the interaction of a low energy electron beam with electro-magnetic fields of the relativistic bunch. The bunch length can be readily deduced from the resulting scatter. In this paper bunch length measurement technique based on a low energy electron beam is introduced. Results of numerical simulations of measurements are presented. A possible setup of such diagnostic system for BERLinPro facility is proposed.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB009
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB010	Compton Polarimetry at ELSA - Beamline and Detector Optimization	photon, polarization, laser, detector	95
	R. Koop, W. Hillert, M.T. Switka ELSA, Bonn, Germany
	Funding: Work supported by DFG within CRC TRR16 The Electron Stretcher Facility ELSA provides a polarized electron beam with energies of 0.5 - 3.2 GeV for double polarization hadron physics experiments. Monitoring the vertical electron polarization by Compton polarimetry in the stretcher ring has several advantages over the established polarization measurement by Moeller polarimetry. The Compton polarimeter setup presented consists of a 40 W cw disk laser featuring two polarized photon beams colliding head-on with the stored electron beam in ELSA. A silicon strip detector measures the vertical intensity profile of the backscattered photons. The reversal of handedness of the laser beam's circular polarization results in a polarization dependent vertical shift of this profile. From a calibration using time dependent polarization build-up due to the Sokolov-Ternov effect, the polarization degree of the electron beam can be extracted. After recent laser repairs as well as beamline and detector modifications, first measurement attempts of the electron's polarization degree were conducted. The performance of the beamline and first measurements are presented.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB010
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB012	A High-Energy-Scrapersystem for the S-DALINAC Extraction - Design and Installation	extraction, linac, vacuum, dipole	101
	L.E. Jürgensen, T. Bahlo, C. Burandt, T. Kürzeder, N. Pietralla, S. Weih, J. Wissmann TU Darmstadt, Darmstadt, Germany F. Hug IKP, Mainz, Germany
	Funding: *Funded by Deutsche Forschungsgemeinschaft under grant No. SFB 634 The superconducting Darmstadt linear electron accelerator (S-DALINAC) of the Institute for Nuclear Physics at Technische Universität Darmstadt delivers electron beams in cw-mode with energies up to 130 MeV. The accelerator consists of a 10-MeV injector and a 30-MeV main linac where superconducting 3-GHz microwave cavities are operated at a temperature of 2 K for beam acceleration. With three recirculation beamlines the main linac can be used up to four times. To improve the energy spread and the energy stability of the beam a new scrapersystem has been developed and installed. It changes the extraction beam line into a dispersion-conserving chicane consisting of four dipole magnets and three scrapers. The system includes scraping of x- and y-halo in two positions as well as improving and stabilizing energy spread on a dispersive part. We will present the design of the system and report on its installation into the accelerator complex.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB012
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB013	Time-resolved Spectral Observation of Coherent THz Pulses at DELTA	radiation, laser, detector, simulation	105
	C. Mai, F.H. Bahnsen, M. Bolsinger, F. Götz, S. Hilbrich, M. Höner, M.A. Jebramcik, S. Khan, N.M. Lockmann, A. Meyer auf der Heide, R. Molo, R. Niemczyk, G. Shayeganrad, M. Suski, P. Ungelenk, D. Zimmermann DELTA, Dortmund, Germany
	Funding: Work supported by the BMBF (05K13PEC), the DFG (INST 212/236-1) and the state of NRW. Coherent THz pulses induced by a laser-electron interac- tion are routinely produced and observed at DELTA, a 1.5- GeV synchrotron light source operated by the TU Dortmund University. At a dedicated THz beamline, measurements using a Fourier-transform spectrometer have been performed between 1 THz and 7 THz. Recently, an ultrafast Schottky- diode detector and a novel polarizing Fourier-transform spec- trometer were installed, which enable turn-by-turn-resolved spectral measurements in the frequency range below 1 THz. The commissioning results of the new spectrometer and simulations are presented.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB013
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB015	Technical Design Considerations About the SINBAD-ARES Linac	linac, laser, gun, acceleration	112
	B. Marchetti, R.W. Aßmann, U. Dorda, K. Flöttmann, M. Hachmann, I. Hartl, J. Herrmann, M. Hüning, G. Kube, F. Ludwig, F. Mayet, M. Pelzer, I. Peperkorn, S. Pfeiffer, H. Schlarb, M. Titberidze, G. Vashchenko, M.K. Weikum, L. Winkelmann, K. Wittenburg, J. Zhu DESY, Hamburg, Germany R. Rossmanith KIT, Karlsruhe, Germany
	The SINBAD facility (Short and INnovative Bunches and Accelerators at Desy) is foreseen to host various experiments in the field of production of ultra-short electron bunches and novel high gradient acceleration technique. The SINBAD linac, also called ARES (Accelerator Research experiment at SINBAD), will be a conventional S-band linear RF accelerator allowing the production of low charge (0.5 pC - few pC) ultra-short electron bunches (FWHM, length <= 1 fs - few fs) having 100 MeV energy. In this paper we present the current status of the technical design considerations, motivate the foreseen diagnostics for the RF gun commissioning and present examples of foreseen applications.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB015
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB017	Design Issues for the Optical Transition Radiation Screens for theELI-NP Compton Gamma Source	radiation, simulation, linac, laser	118
	M. Marongiu, A. Giribono, A. Mostacci, V. Pettinacci INFN-Roma, Roma, Italy D. Alesini, E. Chiadroni, F. Cioeta, G. Di Pirro, V.L. Lollo, L. Pellegrino, V. Shpakov, A. Stella, C. Vaccarezza, A. Variola INFN/LNF, Frascati (Roma), Italy A. Cianchi INFN-Roma II, Roma, Italy L. Palumbo University of Rome La Sapienza, Rome, Italy
	A high brightness electron LINAC is being built in the Compton Gamma Source at the ELI Nuclear Physics facility in Romania. To achieve the design luminosity, a train of 32, 16 ns spaced, bunches with a nominal charge of 250 pC will collide with the laser beam in the interaction point. Electron beam spot size is measured with optical transition radiation profile monitors. In order to measure the beam properties along the train, the screens must sustain the thermal stress due to the energy deposited by the bunches; moreover the optical radiation detecting system must have the necessary accuracy and resolution. This paper deals with the analytical studies as well as numerical simulations to investigate the thermal behaviour of the screens impinged by the nominal bunch; the design and the performance of the optical detection line is discussed as well.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB017
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB018	Metrological Characterization of the Bunch Length Measurement by Means of a RF Deflector at the ELI-NP Compton Gamma source	linac, simulation, laser, brightness	122
	L. Sabato U. Sannio, Benevento, Italy D. Alesini, C. Vaccarezza, A. Variola INFN/LNF, Frascati (Roma), Italy P. Arpaia CERN, Geneva, Switzerland P. Arpaia, A. Liccardo Naples University Federico II, Science and Technology Pole, Napoli, Italy A. Giribono University of Rome La Sapienza, Rome, Italy A. Mostacci, L. Palumbo Rome University La Sapienza, Roma, Italy L. Sabato INFN-Napoli, Napoli, Italy
	Bunch length measurement in linac can be carried out using a RF deflector, which provides a transverse kick to the beam. The transverse beam size on a screen, placed after the RF deflector, represents the bunch length. In this paper, the metrological characterization of the bunch length measurement technique is proposed. The uncertainty and the systematic errors are estimated by means of a sensitivity analysis to the measurement parameters. The proposed approach has been validated through simulation by means of ELEGANT code on the parameters interesting for the electron linac of the Compton source at the Extreme Light Infrastructure - Nuclear Physics (ELI-NP).
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB018
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB019	Quadrupole Scan Emittance Measurements for the ELI-NP Compton Gamma Source	emittance, quadrupole, linac, laser	126
	A.R. Rossi, A. Bacci, L. Serafini Istituto Nazionale di Fisica Nucleare, Milano, Italy E. Chiadroni, C. Vaccarezza, A. Variola INFN/LNF, Frascati (Roma), Italy A. Cianchi Università di Roma II Tor Vergata, Roma, Italy C. Curatolo, I. Drebot Universita' degli Studi di Milano e INFN, Milano, Italy A. Giribono, A. Mostacci University of Rome La Sapienza, Rome, Italy V. Petrillo, M. Rossetti Conti Universita' degli Studi di Milano & INFN, Milano, Italy
	The high brightness electron LINAC of the Compton Gamma Source at the ELI Nuclear Physics facility in Romania is accelerating a train of 32 bunches with a nominal charge of 250 pC and nominal spacing of 16 ns. To achieve the design gamma flux, all the bunches along the train must have the designed Twiss parameters. Beam sizes are measured with optical transition radiation monitors, allowing a quadrupole scan for Twiss parameters measurements. Since focusing the whole bunch train on the screen may lead to permanent screen damage, we investigated non-conventional scans such as scans around a maximum of the beam size or scans with a controlled minimum spot size. This paper discusses the implementation issues of such a technique in the actual machine layout.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB024	Electron Cloud Measurements at J-PARC Main Ring	detector, vacuum, proton, extraction	137
	B. Yee-Rendón, H. Kuboki, R. Muto, K. Satou, M. Tomizawa, T. Toyama, M. Uota KEK, Ibaraki, Japan
	Electron cloud instability is presented in most of the high intensity proton rings. During the Slow beam extraction (SX) mode at Main Ring of J-PARC, signals related with its formation were observed. An electron cloud detector is installed downstream of the ElectroStatic Septum (ESS), to measure the electron signal. Additionally, scintillation detector with photomultiplier, a proportional counter and photo-diode were set closely to the electron cloud detector to observe the beam lost. This paper presents the measurements of the electron cloud and some of the conditions which support its creation, for instance the signal of lost particle from the beam loss monitors, the residual gas in the vacuum duct by using vacuum pressure gauges, etc.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB024
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB026	Frequency and Time Domain Measurement of Coherent Transition Radiation	laser, vacuum, radiation, polarization	143
	K. Kan, M. Gohdo, T. Kondoh, I. Nozawa, J. Yang, Y. Yoshida ISIR, Osaka, Japan
	Ultrashort electron beams are essential for light sources and time-resolved measurements. Electron beams can emit terahertz (THz) pulses using coherent transition radiation (CTR). Michelson interferometer is one of can-didates for analyzing the pulse width of an electron beam based on frequency-domain analysis. Recently, electron beam measurement using a photoconductive antenna (PCA) based on time-domain analysis has been investi-gated. In this paper, to improve beam diagnostics of ul-trashort electron beam, investigation of characteristics of a PCA for generation and frequency and time-domain measurement of THz pulses was conducted. * I. Nozawa et al., Phys. Rev. ST Accel. Beams 17, 072803 (2014). ** K. Kan et al., Appl. Phys. Lett. 102, 221118 (2013).
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB026
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB027	Beam Parameter Measurement After Relocation of S-Band Linear Accelerator	linac, gun, simulation, laser	146
	I. Nozawa, M. Gohdo, K. Kan, T. Kondoh, J. Yang, Y. Yoshida ISIR, Osaka, Japan
	Ultrashort electron bunches have been applied in many scientific fields including accelerator physics and radiation chemistry. Pulse radiolysis is application in radiation chemistry, which is a pump-probe measurement using an electron bunch and a laser pulse. Our laboratory aims to generate the electron bunches with durations of less-than femtoseconds using an S-band linear accelerator (linac) at Osaka University in order to improve the time resolution of the pulse radiolysis system. Recently, the linac system was relocated for expanding application using ultrashort electron bunches. The parameters of generated electron bunches including the bunch lengths will be reported.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB027
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB029	Development Status of Linear Focal Cherenkov Ring Camera	vacuum, laser, photon, experiment	152
	K. Nanbu, T. Abe, H. Hama, F. Hinode, S. Kashiwagi, T. Muto, I. Nagasawa, H. Saito, K. Takahashi, C. Tokoku Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
	Linear focal Cherenkov ring camera (LFC-Camera) has been developed for single shot measurement of longitudinal phase space distribution of quasi-relativistic electron beam, where the electron's velocity still depends on its energy. The LFC-camera employs velocity dependence of opening angle of Cherenkov light produced by electron beam to observe its energy (momentum) distribution. Since the Cherenkov light contains the time information if the radiator medium is thin enough, we can get the longitudinal phase space distribution measuring both time and energy spectra simultaneously using a streak camera. We employ a thin silica aerogel with water-free hydrophobic treatment as Cherenkov radiator. We have evaluated characteristics of the silica aerogel radiator, and demonstration of the LFC-camera at a beam diagnosis section of t-ATCS is being proceeded.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB029
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB030	Development of an EO Sampling Method for THz Pulse Detection	laser, radiation, polarization, experiment	155
	T. Toida, M. Washio, R. Yanagisawa Waseda University, Tokyo, Japan K. Sakaue Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan
	We have been studying an S-band Cs-Te photo-cathode rf gun at Waseda Univ. The high quality electron beam produced by the rf gun is used to generate a high-power coherent terahertz pulse via Cherenkov radiation. This terahertz pulse can be applied to terahertz imaging and material analysis. As a preliminary step towards material analysis, we conducted experiments on terahertz time domain spectroscopy by EO sampling method to reveal major parameters of the terahertz pulse such as the pulse form and the spectrum. EO sampling method has high frequency response and suitable for high peak power terahertz pulses. In terahertz time domain spectroscopy, the duration of the probe pulse needs to be much faster than that of the terahertz pulse. Therefore, we developed a mode locked Yb-fiber laser based on nonlinear polarization rotation as a reliable and cost-effective ultra-fast probe light source. The laser generates 3.80 ps chirped pulses which are compressed to 213 fs with a grating pair. In this conference, we will report the performance of the Yb-fiber laser and results of EO sampling experiments.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB030
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB033	The Influence of Strip-line BPMs' Measuring Results Made by Edge of the Ultra-relativistic Electron Beam	simulation, wakefield, positron, linac	161
	S.Z. Wang, N. Gan, X. Huang IHEP, Beijing, People's Republic of China
	This paper describes the impact on the measuring results of the stripline beam position monitor (BPM) produced by the edge of the ultra-relativistic electron beam when we take the transverse size of the beam into account. Simulations have been made by using the Wakefield Solver of CST Particle Studio. And the result of this influence at different ratio of beam horizontal width σ and the BPM inner diameter a has been obtained. This kind of influence has been observed in the stripline BPMs in the transfer line of Beijing Positron Electron Colliders upgraded version II (BEPCII). The research is useful when we design the inner diameter of the stripline BPMs for ultra-relativistic electron beam, meanwhile it provides reference to distinguish the invalid ones from the measuring results obtained by the stripline BPMs in the ultra-relativistic situation.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB033
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB039	Design of Bunch Length Measurement System at the IRFEL Using a Martin-Puplett Interferometer	radiation, detector, polarization, vacuum	178
	T.Y. Zhou, X.Y. Liu, P. Lu, B.G. Sun, L.L. Tang, F.F. Wu, Y.L. Yang, Z.R. Zhou USTC/NSRL, Hefei, Anhui, People's Republic of China
	Funding: Supported by the National Science Foundation of China (11575181, 11175173) Electron bunch length measurement is of great significance for optimizing IRFEL performance. An optical autocorrelation system using coherent transition radiation (CTR) would be set up to measure the electron bunch length at the IRFEL. CTR can be occurred when short electron bunches traverse a vacuum-metal interface. A Martin-Puplett interferometer allowed measurement of the autocorrelation of the CTR signal. The basic principle and the main components of Martin-Puplett interferometer are elaborated in this paper.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB039
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB041	Modified Trigger Mode of Streak Camera to Measure Bunch Longitudinal Distribution in HLS II	optics, controls, brightness, hardware	184
	H. Li, X.Y. Liu, P. Lu, B.G. Sun, L.L. Tang, J.G. Wang, F.F. Wu, Y.L. Yang, Z.R. Zhou USTC/NSRL, Hefei, Anhui, People's Republic of China
	Funding: Supported by the National Science Foundation of China (11575181, 11175173) In Hefei Light Source, the streak camera was used to measure the bunch length and longitudinal distribution using synchronous light. As the RF frequency of HLS II was 204MHz, the streak camera worked at the frequency of 102MHz (half of 204MHz). Because of the bunch lengthening, the streak camera faced the problem, the streak image on the phosphor screen will overlap when the bunch length was above 200.5ps@5% linear error and 10% overlap. In order to solve this problem, an effective solution was to change the working frequency of the streak camera to 136MHz (two thirds of 204MHz), and then the streak image on the phosphor screen will overlap when the bunch length was above 285.6ps@5% linear error and 10% overlap. So a front-end electronic was needed before the synchronizing signals feed into the streak camera. The front-end electronic was designed to convert the 204MHz synchronizing signal to 136MHz.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB041
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB042	Design and Simulation of Button Beam Position Monitor for IR-FEL*	vacuum, FEL, simulation, electronics	187
	X.Y. Liu, P. Lu, B.G. Sun, L.L. Tang, F.F. Wu, Y.L. Yang, T.Y. Zhou, Z.R. Zhou USTC/NSRL, Hefei, Anhui, People's Republic of China
	Funding: * Supported by the National Science Foundation of China (11575181, 11175173) A new button-type beam position monitor(BPM) was designed for the IR-FEL project. Firstly, the longitudinal size of BPM needs to be short enough to save space because the entire machine of IR-FEL is very compact. And in the matter of installation problem, all four electrodes are deviated 30 degrees from the horizontal axis. Then, according to these two limited conditions and beam parameters, we builded up a simple model and did some simulated calculations to ensure a good performance of position resolution, which should be better than 50μm. The simulations include an estimation of induced signals in both time and frequency domains, horizontal and vertical sensitivities, mapping figures and so on. This button BPM will be manufactured in the near future and then we can do some off-line experiments to test it. # Corresponding author (email: bgsun@ustc.edu.cn)
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB042
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB046	Design and Calculation Error Analysis of a High Order Mode Cavity Bunch Length Monitor	cavity, positron, simulation, linac	196
	J.G. Guo, Q. Luo, Z.R. Zhou USTC/NSRL, Hefei, Anhui, People's Republic of China
	Funding: National Science Foundation of China (11375178) and Fundamental Research Funds for the Central Universities (WK2310000046). A two-cavity bunch length monitor for linac of positron source is designed. Fifth harmonic cavity resonates at 14.28 GHz (fifth harmonic of the linac fundamental frequency 2.856 GHz) with mode TM020, as this mode could provide larger cavity radius. Each cavity equipped with a filter to suppress unwanted signal. An improved bunch length calculation method was proposed. A simulation was conducted in CST Particle Studio for beam current from 100-300 mA, bunch length from 5-10 ps. Bunch length was calculated and compared by these two methods
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB046
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB048	Bunch Length Measurement at Bunch by Bunch in Harmonics Method at Shanghai SSRF Storage Ring	experiment, injection, storage-ring, synchrotron-radiation	199
	L.W. Duan, Y.B. Leng, R.X. Yuan SINAP, Shanghai, People's Republic of China N. Zhang SSRF, Shanghai, People's Republic of China
	Harmonics method in frequency domain is an effective and inexpensive bunch length measurement method. With advances in technology, it is possible to do bunch length measurement at bunch by bunch using electronic method. We design and make an electronic system to realize metering at bunch by bunch, and believe it has reasonable bunch length resolution. All selected harmonic signals will be mixed down to 500 MHz and digitized at bunch-by-bunch rate by a multi-channel DBPM processor. The primary beam experiment results will be presented and discussed in this paper.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB048
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB049	Beam Experiment of Low Q CBPM Prototype for SXFEL	cavity, simulation, HOM, FEL	202
	J. Chen, L.W. Lai, Y.B. Leng, L.Y. Yu, R.X. Yuan SINAP, Shanghai, People's Republic of China
	To meet the high resolution beam position measurement requirement of micron or sub-micron for shanghai soft X-ray free electron laser (SXFEL) under construction, the cavity beam position monitor (CBPM) operating at C-band and the corresponding electronic has been designed by SINAP. In this paper, the design and optimize of the newly low Q cavity BPM is mentioned, the beam test was conducted on the Shanghai Deep ultraviolet free electron laser (SDUV-FEL) facility. CBPM signal processors including broadband oscilloscope and home-made digital BPM processor have been used to evaluate the system performance as well. The beam experimental result, which matched with MAFIA simulation very well, will be presented and discussed in this paper.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB049
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB051	Cavity BPM Performance Online Evaluation using PCA Method	cavity, experiment, factory, coupling	208
	Y.B. Leng, L.W. Lai, L.Y. Yu, R.X. Yuan SSRF, Shanghai, People's Republic of China J. Chen, Z.C. Chen SINAP, Shanghai, People's Republic of China
	Funding: NSFS 11575282 This article proposes a new test method to evaluate the performance of cavity beam position monitors using the actual beam as the exciting signal. The new method sepa-rates the signals of different modes and improves the measurement accuracy by eliminating unwanted cou-plings from other sources.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB051
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB054	A High Sensitivity Faraday Cup for Ultrashort Electron Bunches	simulation, gun, laser, experiment	214
	S. Setiniyaz, I.H. Baek, B.A. Gudkov, B. Han, K.H. Jang, Y.U. Jeong, H.W. Kim, S.V. Miginsky, J.H. Nam, S. Park, N. Vinokurov KAERI, Daejon, Republic of Korea S.V. Miginsky, N. Vinokurov BINP SB RAS, Novosibirsk, Russia
	The UED (Ultrafast Electron Diffraction) beamline of KAERI (Korea Atomic Energy Research Institute) WCI (World Class Institute) Center has been successfully commissioned. A S-band co-axial RF photogun with 1.5 cylindrically symmetric cells was used to remove multiple modes of the electric filed inside the cavity. It is designed to generate sub-picosecond electron bunches with energy up to 3.3~MeV. We have developed a system consists of an in-air Faraday cup (FC) and a preamplifier for charge measurement. Tests performed utilizing 3.3~MeV electrons show the system were able to measure ultrashort bunches with tens of femtosecond pulse duration at 10 fC sensitivity. In this paper, we shall present the design, calibration and test results of this system.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB054
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR001	Micro-mover Development and Test in the PAL-XFEL	solenoid, gun, cavity, controls	229
	B.G. Oh, J.H. Han, H. Heo, J.H. Hong, H.-S. Kang, C. Kim, D.E. Kim, K.-H. Park, Y.J. Suh PAL, Pohang, Kyungbuk, Republic of Korea
	Two micro-movers, which are able to control the horizontal, vertical and longitudinal positions as well as the yaw and pitch angles remotely, were developed and installed in the PAL-XFEL linac. The solenoid micro-mover in the gun section allows beam-based alignment of an electron beam to the solenoid field and the gun RF field. The X-band cavity micro-mover minimizes the transverse wake field effect caused by transverse misalignment between the beam and X-band cavity. Two micro-movers has similar specifications and the same mechanism, but the sizes are different from each other. In this paper, we present the design, manufacture and test results of the micro-movers.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR001
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR003	Electron Bunch Length Measurement Using Coherent Radiation Source of fs-THz accelerator at Pohang Accelerator Laboratory	radiation, linac, experiment, target	235
	J.H. Ko, I.S. Ko POSTECH, Pohang, Kyungbuk, Republic of Korea S.H. Jung, H.-S. Kang, I.S. Ko, J. Park PAL, Pohang, Kyungbuk, Republic of Korea
	A Michelson interferometer was installed at the femtosecond (fs) terahertz (THz) Accelerator of Pohang Accelerator Laboratory(PAL) to measure a subpicosecond order electron bunch length. To measure an ultra-short electron bunch length, we use reconstruction process and fast fourier transform. Currently, we are generating THz radiation with the pulse energy of 7μJ by means of coherent transition radiation (CTR) from a 65-MeV electron beam of the fs-THz accelerator. In this paper, we show the how to make a longitudinal distribution of electron bunch and the radiation intensity difference between CTR and Coherent edge radiation (CER) for nondestructive electron bunch length measurement. And we report the measurement methods to get the fine electron bunch length information.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR003
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR009	Development of Large Aperture Faraday-Cup for LEBT of KHIMA.	ion, proton, ECR, beam-transport	241
	J.G. Hwang KIRAMS/KHIMA, Seoul, Republic of Korea T.K. Yang KIRAMS, Seoul, Republic of Korea
	Funding: This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIP) (no. NRF-2014M2C3A1029534). Since an aperture of a low energy beam transport line of the KHIMA is quite large, 100 mm, to minimize an uncontrolled beam loss, large aperture Faraday-cup with the diameter of 100 mm is installed to measure the beam current from the electron cyclotron resonance ion source (ECR-IS) and to identify the ion species using analyzing magnet. The suppression ring is designed to reduce the repelling electrons for an accurate measurement. The Faraday-cup has the cooling channel with the heat capability of 100 W to recover the heat from the ion beam for safety during the operation. In order to reduce the noise propagation from the cooling channel, the cooling channel is insulated with the cup. In this presentation, we show the physical modeling, mechanical aspect for design the large aperture Faraday-cup, and the result of in-beam test with the ECR-IS in KHIMA.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR009
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR013	Development, Calibration and Application of New-generation Dissectors with Picosecond Temporal Resolution	laser, radiation, operation, positron	251
	O.I. Meshkov, O. Anchugov, V.L. Dorohov, G.Y. Kurkin, A.V. Petrozhitskii, D.A. Shvedov, E.I. Zinin BINP SB RAS, Novosibirsk, Russia P.B. Gornostaev, M.Ya. Schelev, E.V. Shashkov, A. V. Smirnov, A.I. Zarovskii GPI, Moscow, Russia
	Funding: The presented experimental results were implemented due to financial support of the Russian Science Foundation (Projects N 14-29-00295) A dissector is an electron-optical device designed for measurement of periodic light pulses of subnanosecond and picosecond duration. LI-602 dissector developed at BINP is widely used for routine measurements of a longitudinal profile of electron and positron beams at BINP electron-positron colliders and other similar installations]. This dissector is a part of many optical diagnostic systems and provides temporal resolution of about 20 ps. Recently* a new generation of picosecond dissectors were created on the basis of the PIF-01/S1 picosecond streak-image tube designed and manufactured at the General Physics Institute Photoelectronics Department (Moscow). The device has demonstrated a temporal resolution of 3-4 ps (FWHM). The procedure of temporal resolution calibration and results of application of the new-generation picosecond dissector are given in this work. *E.I. Zinin, O.I. Meshkov. JINST, 2015 1748-0221 10 P10024 doi:10.1088/1748-0221/10/10/P10024
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR013
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR015	Optical Fibers as a Tool for Gamma Beam Diagnostics at Medical Electron Accelerators	betatron, target, detector, radiation	258
	A.I. Novokshonov, V.I. Bespalov, A. Potylitsyn, D.A. Shkitov, S.R. Uglov, A.V. Vukolov TPU, Tomsk, Russia
	Funding: This work was partially supported by the Russian Ministry of Education and Science within the program "Nauka" Grant № 3.709.2014/K. The existing techniques for gamma beam diagnostics at medical accelerators based on X-ray films have several disadvantages such as insufficient spatial resolution, difficult realization and off-line mode. In the works,* a feasibility of Cherenkov radiation (CR) in glass fibers for charged particle beam diagnostics was demonstrated. An application of glass fibers scanning for gamma beam diagnostics may have a lot advantages including a possibility of on-line measurements. For this goal we used optical fiber with 0.6 mm diameter and length up to 10 m. An efficiency of CR generation in such fibers and signal attenuation in a long fiber were investigated using the Tomsk microtron electron beam. The shape of gamma beam field produced by the medical SL-75-5MT 6 MeV electron accelerator was measured using the proposed technique. It is shown there it is possible to measure not only gamma beam spatial distribution, but also its angular distribution. * Wulf, F. and Korfer, M. 2009 Proc. DIPAC2009 411. ** Murokh, A., Agustsson, R., Boucher, S., Frigola, P., Hodgetts, T., Ovodenko, A., Ruelas, M. and Tikhoplav, R. 2012 Proc. IPAC2012 996.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR015
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR017	Design and Simulations of the Cavity BPM Readout Electronics for the ELI-NP Gamma Beam System	cavity, electronics, simulation, linac	264
	M. Cargnelutti, B.B. Baricevic I-Tech, Solkan, Slovenia A. Mostacci University of Rome La Sapienza, Rome, Italy S. Pioli, M. Serio, A. Stella, A. Variola INFN/LNF, Frascati (Roma), Italy
	The Extreme Light Infrastructure - Nuclear Physics (ELI-NP) facility will provide a high intensity laser and a very intense gamma beam which will be used in a broad range of experiments. The gamma beam is obtained through incoherent Compton back-scattering of a laser light off a high brightness electron beam provided by a 700MeV warm LINAC. Electrons are accelerated in trains with up to 32 bunches, each one separated by 16ns. In the laser-electron interaction region, every bunch needs to be monitored with a resolution below 1μm RMS. To achieve this performance, a low-Q cavity beam position monitor will be used in combination with a dedicated data acquisition system able to perform bunch-by-bunch beam position measurements with sub-μm resolution. Using fast A/D converters and specific digital filtering, the readout system proposes an alternative measurement concept. The requirements of the system, its design and the results from the simulations will be presented.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR017
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR021	Lifetime and Operational Criteria of Proton Beam Instrumentation in the ESS Target Station	proton, radiation, target, monitoring	276
	Y. Lee, T.J. Shea, C.A. Thomas ESS, Lund, Sweden
	At the European Spallation Source, a 2 GeV, 5 MW proton beam will be delivered from a superconducting linear accelerator to target at a 4% duty factor, which poses demanding requirements on target station design. To tune the beam delivery system and to protect the target station components, the current density, the halo distribution, and the position of the proton beam shall be measured. To provide this functionality, a suite of beam monitoring devices will be deployed in the target monolith, including a multi-wire grid for the beam profile monitoring, thermo-couple assemblies and secondary emission blades for aperture monitoring, and a beam footprint imaging system consisting of optical components and luminescent coatings. Since these devices are exposed to particles that deposit energy and cause a high rate of radiation damage, it is a significant challenge to ensure full functionality. In this paper, material selection, lifetime estimates and operational criteria for these beam-monitoring devices are presented. A number of particle transport and finite-element simulations are performed for analyses, and an empirical validation plan is presented.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR023	Surface Characterization and Field Emission Measurements of Copper Samples inside a Scanning Electron Microscope	controls, vacuum, experiment, radio-frequency	283
	J. Ögren, V.G. Ziemann Uppsala University, Uppsala, Sweden S.H.M. Jafri, K. Leifer Uppsala University, Department of Engineering Sciences, Uppsala, Sweden
	Vacuum breakdown in normal-conducting accelerating structures is a limiting factor for high gradient acceleration. Many aspects of the physics governing the breakdown process and its onset are yet to be fully understood. At Uppsala University we address these questions with an in-situ experimental setup mounted in an environmental scanning electron microscope. It consists of a piezo motor driven tungsten needle and a sample surface mounted on a piezo stage, allowing for nano-meter 3D-position control. One of the piezo motors controls the needle-sample gap while the two other scan across the surface. A DC-voltage up to 1 kV is applied across the gap and field emission currents from a copper surface are measured with an electrometer. Here we present the setup and some initial results.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR023
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR024	A Versatile Beam Loss Monitoring System for CLIC	quadrupole, beam-losses, background, cavity	286
	M. Kastriotou, S. Döbert, W. Farabolini, E.B. Holzer, E. Nebot Del Busto, F. Tecker CERN, Geneva, Switzerland M. Kastriotou, E. Nebot Del Busto, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom M. Kastriotou, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	The design of a potential CLIC beam loss monitoring (BLM) system presents multiple challenges. To successfully cover the 48 km of beamline, ionisation chambers and optical fibre BLMs are under investigation. The former fulfils all CLIC requirements but would need more than 40000 monitors to protect the whole facility. For the latter, the capability of reconstructing the original loss position with a multi-bunch beam pulse and multiple loss locations still needs to be quantified. Two main sources of background for beam loss measurements are identified for CLIC. The two-beam accelerator scheme introduces so-called crosstalk, i.e. detection of losses originating in one beam line by the monitors protecting the other. Moreover, electrons emitted from the inner surface of RF cavities and boosted by the high RF gradients may produce signals in neighbouring BLMs, limiting their ability to detect real beam losses. This contribution presents the results of dedicated experiments performed in the CLIC Test Facility to quantify the position resolution of optical fibre BLMs in a multi-bunch, multi-loss scenario as well as the sensitivity limitations due to crosstalk and electron field emission.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR024
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR035	Bunch Length Measurements using a Transverse Deflecting Cavity on VELA	gun, cavity, laser, simulation	323
	J.W. McKenzie, S.R. Buckley, L.S. Cowie, P. Goudket, M. Jenkins, B.L. Militsyn, A.J. Moss, A.E. Wheelhouse STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom G. Burt Cockcroft Institute, Lancaster University, Lancaster, United Kingdom A. Wolski The University of Liverpool, Liverpool, United Kingdom
	The VELA facility at Daresbury Laboratory in the UK includes a 5 MeV/c 2.5 cell S-band photoinjector gun. This gun operates in the "blow-out" regime with a sub-200 fs length drive laser: the resulting bunch length is determined by space-charge effects. We present measurements made with an S-band transverse deflecting cavity to characterise the bunch length as a function of charge, and as a function of the gun operating phase.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR035
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR041	Experimental and Theoretical Studies of the Properties of Coherent Smith-Purcell Radiation	radiation, polarization, background, experiment	344
	F. Bakkali Taheri, R. Bartolini, G. Doucas, I.V. Konoplev, A. Reichold JAI, Oxford, United Kingdom J. Barros, N. Delerue LAL, Orsay, France R. Bartolini DLS, Oxfordshire, United Kingdom C.I. Clarke SLAC, Menlo Park, California, USA
	Funding: This work was supported (in parts) by the UK Science and Technology Facilities Council (STFC UK) through grant ST/M003590/1 and The Leverhulme Trust through the International Network Grant IN-2015-012 Previous studies have demonstrated that coherent Smith-Purcell radiation (cSPr) can be used for relativistic electron bunch time profile reconstruction at pico-second and femtosecond scales. The E203 experiments undertaken in May 2015 at FACET (SLAC) were dedicated to the study of some properties of cSPr, namely the azimuthal distribution and the polarization of the radiation. The experimental set up description which allowed such studies will be presented along with the results. To understand the experimental data both semi-analytical and numerical models were studied. The semi-analytical approach was based on the surface-current model, and the 3D particle-in-cell code VSim was used for numerical modeling. The experimental and theoretical studies are compared.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR041
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR045	High Resolution and Dynamic Range Characterisation of Beam Imaging Systems	optics, laser, target, simulation	354
	C.P. Welsch, R.B. Fiorito, J. Wolfenden Cockcroft Institute, Warrington, Cheshire, United Kingdom M. Bergamaschi, R. Kieffer, T. Lefèvre, S. Mazzoni CERN, Geneva, Switzerland R.B. Fiorito, C.P. Welsch, J. Wolfenden The University of Liverpool, Liverpool, United Kingdom P. Karataev, K.O. Kruchinin Royal Holloway, University of London, Surrey, United Kingdom P. Karataev, K.O. Kruchinin JAI, Egham, Surrey, United Kingdom
	Funding: Work supported by the EU under grant agreement 624890 and the STFC Cockcroft Institute core grant ST/G008248/1. Any imaging system requires the use of various optical components to transfer the light from the source, e.g. optical radiation generated by a charged particle beam, to the sensor. The impact of the transfer optics on the image resolution is often not well known. To improve this situation, the point spread function (PSF) of the optical system must be measured, preferably, with high dynamic range. For this purpose we have created an intense, small (~ 1 μm) point source using a high quality laser and special focusing optics; and introduced a digital micro-mirror array in the optical system to substantially increase its dynamic range. The PSFs of optical systems that are currently being developed for high resolution, high dynamic range beam imaging using optical transition and diffraction radiation are measured and compared to Zemax simulations. The goal of these studies is to systematically understand and mitigate any ill effects on the PSF due to aberrations, diffraction and misalignment of the components of the imaging system. We present the results of our measurements and simulations.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR045
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR046	Characterizing Supersonic Gas Jet-based Beam Profile Monitors	ion, simulation, vacuum, diagnostics	357
	H.D. Zhang, A.S. Alexandrova, A. Jeff, V. Tzoganis, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom A.S. Alexandrova, A. Jeff, V. Tzoganis, C.P. Welsch, H.D. Zhang The University of Liverpool, Liverpool, United Kingdom A. Jeff CERN, Geneva, Switzerland
	Funding: Work supported by EU under contracts 215080 and 289191, Helmholtz Association (VH-NG-328) and STFC under the Cockcroft Institute core grant ST/G008248/1. The next generation of high power, high intensity accelerators requires non-invasive diagnostics, particularly beam profile monitors. Residual gas-based diagnostics such as ionization beam profile or beam induced fluorescence monitors have been used to replace commonly used scintillating screens. At the Cockcroft Institute an alternative technique using a supersonic gas jet, shaped into a 45o curtain screen, was developed. It has already demonstrated its superior performance in terms of resolution and signal-to-noise ratio in comparison with residual gas monitors in experimental studies. The performance of this type of monitor depends on the achievable jet homogeneity and quality. Using a movable vacuum gauge as a scanner, the dynamic characteristics of the jet are studied. In this paper we also give an analysis of the resolution for this monitor in detail from the theory and ion drift simulation.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR046
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR052	Single-shot Bunch-by-Bunch Horizontal Beam Size Measurements using a Gated Camera at CesrTA	positron, ion, vacuum, synchrotron-radiation	364
	S. Wang Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA R. Holtzapple CalPoly, San Luis Obispo, California, USA
	Funding: Work supported by NSF NSF PHY-1416318, PHYS-1068662, PHYS-1535696 A visible-light beam size monitor has been built and commissioned to measure transverse beam profiles at CESR-TA. In order to eliminate beam jitter and to study bunch-by-bunch beam dynamics, a fast-gating camera has been utilized to measure single bunch transverse beam profiles. The minimum camera gate width is ~ 3ns which allows us to resolve single bunch beam dynamics along a CesrTA bunch train. Using single bunch interferometry at different bunch currents, we found that the horizontal beam sizes measured by gated camera are consistently less than those measured by a conventional CCD camera, demonstrating the elimination of turn-by-turn beam jitter with single shot capability. By stepping the camera trigger delay, we collected transverse beam profile images from each bunch in a 14ns-spacing 30-bunch train. The horizontal motion of each bunch as well as the horizontal beam size increases dramatically along an electron train but not along positron bunch trains under the same machine condition. The difference in single bunch horizontal dynamics may be a signature for the difference between electron cloud build-up for positron bunch trains versus ions present for electron bunch trains. S.T. Wang, D.L. Rubin, J. Conway, M. Palmer, D. Hartill, R. Campbell, R. Holtzapple, NIMA, 703 (2013) 80
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR052
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR054	Double-slit Interferometer Measurements at SPEAR3	synchrotron, synchrotron-radiation, radiation, optics	368
	C.L. Li, W.J. Zhang East China University of Science and Technology, Shanghai, People's Republic of China M.J. Boland SLSA, Clayton, Australia W.J. Corbett, M. Grinberg SLAC, Menlo Park, California, USA T.M. Mitsuhashi KEK, Ibaraki, Japan Y.H. Xu DongHua University, Songjiang, People's Republic of China W.J. Zhang University of Saskatchewan, Saskatoon, Canada
	The resolution of a conventional telescope used to image visible-light synchrotron radiation is often limited by diffraction effects. To improve resolution, the double-slit interferometer method was developed at KEK and has since become popular around the world. Based on the Van Cittert-Zernike theorem relating transverse source profile to transverse spatial coherence, the particle beam size can be inferred by recording fringe contrast as a function of interferometer slit separation. In this paper, we describe the SPEAR3 double-slit interferometer, develop a theoretical framework for the interferometer and provide experimental results. Of note the double-slit system is 'rotated' about the beam axis to map the dependence of photon beam coherence on angle.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR054
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR059	Development of S-band High Power Load	vacuum, klystron, radio-frequency, radiation	383
	X.C. Meng, H.B. Chen, C. Cheng, Y.-C. Du, Q. Gao, J. Shi, P. Wang, Z.F. Xiong TUB, Beijing, People's Republic of China
	Several types of S-band high power loads have been designed, manufactured and tested successfully in Tsinghua University. The high power loads, which work at 2856 MHz for 10 MW~100 MW range, are made of all stainless steel. In this paper, we will present the design, fabrication and the high power test results.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR059
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW001	A New Buncher for the ESRF Linac Injector	linac, beam-loading, cavity, gun	389
	A.S. Setty, A.S. Chauchat, D. Jousse Thales Communications & Security (TCS), Gennevilliers Cedex, France H. Delamare, J. Jacob, B. Ogier, T.P. Perron, E. Rabeuf, C. Richard, V. Serrière, R. Versteegen ESRF, Grenoble, France
	The electron linac was designed to be able to deliver more than 2.5 A in less than 2 ns at 200 MeV within an energy spread of 1% for positrons production at ESRF . The 200 MeV electron linac was commissioned in 1991. A new gun, a cleaner, a pre-buncher cavity and 4 shielded lenses were tested and installed on the injector in 2008 . Then, a new Buncher for the ESRF electron linac injector was manufactured and commissioned in 2015. Meanwhile, some new settings were performed to reduce the energy spread for both cases: the long pulse mode and the short pulse mode. The simulations and measurements will be presented. D. Tronc et Al. "Electron injector for light source", Proc. EPAC88, Italy, Rome, June 1988. ** T. Perron et Al. "New preinjector for the ESRF booster", Proc. EPAC08, Italy, Genoa, June 2008.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW001
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW003	Thermal Simulation of an Energy Feedback Normal Conducting RF Cavity	cavity, coupling, simulation, operation	396
	M. Fakhari, K. Flöttmann, S. Pfeiffer, H. Schlarb DESY, Hamburg, Germany J. Roßbach University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany A. Yahaghi CFEL, Hamburg, Germany
	Thermal simulation has been performed for an energy feedback normal conducting RF cavity. The cavity is going to be used as a fast actuator to regulate the arrival time of the electron bunches in fs level in FLASH. By measuring the arrival time jitter of one bunch in a bunch train, the designed cavity apply a correcting accelerating or decelerating voltage to the next bunches. The input power of the cavity is provided by a solid state amplifier and will be coupled to the cavity via a loop on the body. To achieve the fs level precision of the arrival time, the cavity should be able to provide accurate accelerating voltage with a precision of 300 eV. We performed thermal simulation to find out the temperature distribution of the cavity and make sure that heating will not affect its voltage precision. The simulation results show that by using two input loops the coupling constant will vary from 4.11 to 4.13 during the operation of the cavity which effect on the bunchs' arrival time would be less than 0.25 fs. While using just one input loop can lead to an error of about 1 fs.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW003
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW006	The RF System of the ELI-NP Gamma Beam Source	LLRF, linac, klystron, network	407
	L. Piersanti, F. Cardelli, L. Palumbo INFN-Roma1, Rome, Italy D. Alesini, M. Bellaveglia, R. Boni, A. Gallo, A. Variola INFN/LNF, Frascati (Roma), Italy F. Cardelli, L. Palumbo, L. Piersanti University of Rome La Sapienza, Rome, Italy G. D'Auria Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	ELI-NP is a linac based gamma-source under construction in Magurele (RO) by the European consortium EuroGammaS led by INFN. Photons with tunable energy (from 0.2 to 19.5 MeV) and with unprecedented intensity and brilliance will be produced by Compton back-scattering between a high quality electron beam (up to 740 MeV), and a 515 nm intense laser pulse. In order to increase the gamma photon flux, the accelerator will operate in multi-bunch at 100 Hz repetition rate, with 32 bunches separated by 16 ns. Three S-band (2856 MHz) RF power plants will feed two room temperature Travelling Wave (TW) structures, a 1.6 cell Standing Wave (SW) S-band gun (which has been manufactured by means of a new technique based on clamped gaskets without brazing) and two SW RF deflectors for longitudinal beam diagnostics. Ten C-band (5712 MHz) RF power plants will feed 12 TW high-order-modes (HOM) damped structures. In this paper, we review the whole ELI-NP RF architecture including the Low Level RF (LLRF) system.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW006
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW010	Property Test of the Q-Factor for High Purity Copper at the Temperature of 20K	cavity, linac, radiation, cryogenics	417
	A. Iino Sokendai, Ibaraki, Japan K. Endo TOYAMA Co., Ltd., Zama-shi, Kanagawa, Japan S. Yamaguchi KEK, Ibaraki, Japan
	A coherent parametric x-ray radiation (PXR) source based on a cryogenic electron linac has been developed by Toyama Co., Ltd, KEK and Nihon University. This accelerator is a C-band normal-conducting compact linac that requires a high Q factor in the accelerating and de-celerating structures. To obtain a high Q factor, the ac-celerating and decelerating structures are operated around 20 K, and are joined by diffusion bonding and are constructed with high-purity 6N8 copper which has very low resistivity in extremely low temperatures. In this study, we report the measurements and calculation of the residual resistance ratio (RRR) for 6N8 copper and oxy-gen-free copper (Class 1) as well as the Q factor for a pillbox cavity made of 6N8 copper and Class 1. The results of a low-power test of this accelerating structure at low temperature are reported. The Q factor for a 6N8 copper pillbox cavity is not much higher than that of a Class 1 pillbox cavity at low temperatures Moreover, the Q factor is saturated when RRR is greater than 500.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW010
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW025	Vacuum RF Breakdown of Accelerating Cavities in Multi-Tesla Magnetic Fields	cavity, vacuum, operation, Windows	444
	D.L. Bowring, A. Moretti, M.A. Palmer, D.W. Peterson, A.V. Tollestrup, K. Yonehara Fermilab, Batavia, Illinois, USA B.T. Freemire IIT, Chicago, Illinois, USA A.V. Kochemirovskiy University of Chicago, Chicago, Illinois, USA P.G. Lane, Y. Torun Illinois Institute of Technology, Chicago, Illinois, USA
	Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359. Ionization cooling of intense muon beams requires the operation of high-gradient, normal-conducting RF structures within multi-Tesla magnetic fields. The application of strong magnetic fields has been shown to lead to an increase in vacuum RF breakdown. This phenomenon imposes operational (i.e. gradient) limitations on cavities in ionization cooling channels, and has a bearing on the design and operation of other RF structures as well, such as photocathodes and klystrons. We present recent results from Fermilab's MuCool Test Area (MTA), in which 201 and 805 MHz cavities were operated at high power both with and without the presence of multi-Tesla magnetic fields. We present an analysis of damage due to breakdown in these cavities, as well as measurements related to dark current and their relation to a conceptual model describing breakdown phenomena.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW025
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW031	Beam Test of a Dielectric Loaded High Pressure RF Cavity for Use in Muon Cooling Channels	cavity, ion, plasma, accelerating-gradient	463
	B.T. Freemire IIT, Chicago, Illinois, USA D.L. Bowring, A. Moretti, D.W. Peterson, A.V. Tollestrup, K. Yonehara Fermilab, Batavia, Illinois, USA A.V. Kochemirovskiy University of Chicago, Chicago, Illinois, USA Y. Torun Illinois Institute of Technology, Chicago, Illlinois, USA
	Funding: This work is supported by the Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359. Bright muon sources require six dimensional cooling to achieve acceptable luminosities. Ionization cooling is the only known method able to do so within the muon lifetime. One proposed cooling channel, the Helical Cooling Channel, utilizes gas filled radio frequency cavities to both mitigate RF breakdown in the presence of strong, external magnetic fields, and provide the cooling medium. Engineering constraints on the diameter of the magnets within which these cavities operate dictate the radius of the cavities be decreased at their nominal operating frequency. To accomplish this, one may load the cavities with a larger dielectric material. A 99.5% alumina ring was inserted in a high pressure RF test cell and subjected to an intense proton beam at the MuCool Test Area at Fermilab. The results of the performance of this dielectric loaded high pressure RF cavity will be presented.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW031
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW035	Wakefield Excitation in Power Extraction Cavity (PEC) of Co-linear X-band Energy Booster (CXEB) in Time Domain (T3P) with ACE3P	cavity, extraction, booster, simulation	477
	T. Sipahi, S. Biedron, S.V. Milton CSU, Fort Collins, Colorado, USA
	In our previous papers we provided the general concept and the design details of our proposed Co-linear X-band Energy Booster (CXEB) as well as more advanced 3D simulations of our system using the frequency domain solvers OMEGA3P and S3P of the ACE3P Suite. Here, using the time domain solver T3P of ACE3P, we provide the single bunch and multiple bunch wakefield excitations resulting from a Gaussian bunch. The related power extraction mechanism for our traveling wave (TW) X-band power extraction cavity (PEC) are also discussed further.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW035
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW036	Frequency Domain Simulations of Co-linear X-band Energy Booster (CXEB) RF Cavity Structures and Passive RF Components with ACE3P	cavity, laser, impedance, extraction	480
	T. Sipahi, S. Biedron, S.V. Milton CSU, Fort Collins, Colorado, USA
	Due to their higher intrinsic shunt impedance X-band accelerating structures offer significant gradients with relatively modest input powers, and this can lead to more compact light sources. At the Colorado State University Accelerator Laboratory (CSUAL) [1] we would like to adapt this technology to our 1.3-GHz, L-band accelerator system using a passively driven 11.7 GHz traveling wave X-band configuration that capitalizes on the high shunt impedances achievable in X-band accelerating structures in order to increase our overall beam energy in a manner that does not require investment in an expensive, custom, high-power X-band klystron system. Here we provide the comparisons of the important parameters achieved using SUPERFISH and OMEGA3P for our Co-linear X-band Energy Booster (XCEB) system that will allow us to achieve our goal of reaching the maximum practical net potential across the X-band accelerating structures while driven solely by the beam from the L-band system.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW036
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW037	FEL Simulation Using Distributed Computing	simulation, FEL, GPU, distributed	483
	J. Einstein, S. Biedron, H. Freund, S.V. Milton, P.J.M. van der Slot CSU, Fort Collins, Colorado, USA G. Bernabeu Altayo Fermi National Accelerator Laboratory, Batavia, Illinois, USA S. Biedron University of Ljubljana, Faculty of Electrical Engineering, Ljubljana, Slovenia J. Einstein Fermilab, Batavia, Illinois, USA P.J.M. van der Slot Twente University, Laser Physics and Non-Linear Optics Group, Enschede, The Netherlands
	While simulation tools are available and have been used regularly for simulating light sources, the increasing availability and lower cost of GPU-based processing opens up new opportunities. This poster highlights a method of how accelerating and parallelizing code processing through the use of COTS software interfaces.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW037
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW038	Measurements of Copper RF Surface Resistance at Cryogenic Temperatures for Applications to X-Band and S-Band Accelerators	cavity, cryogenics, experiment, coupling	487
	A.D. Cahill, A. Fukasawa, J.B. Rosenzweig UCLA, Los Angeles, California, USA G.B. Bowden, V.A. Dolgashev, M.A. Franzi, S.G. Tantawi, P.B. Welander, C. Yoneda SLAC, Menlo Park, California, USA J. Guo JLab, Newport News, Virginia, USA Y. Higashi OIST, Onna-son, Okinawa, Japan
	Funding: Funding from DOE SCGSR and DOE/SU Contract DE-AC02-76-SF00515 Recent SLAC experiments with cryogenically cooled X-Band standing wave copper accelerating cavities have shown that these structures can operate with accelerating gradients of ~250 MV/m and low breakdown rates. These results prompted us to perform systematic studies of copper rf properties at cryogenic temperatures and low rf power. We placed copper cavities into a cryostat cooled by a pulse tube cryocooler, so cavities could be cooled to 4K. We used different shapes of cavities for the X-Band and S-Band measurements. Properties of the cavities were measured using a network analyzer. We calculated rf surface resistance from measured Q0 and Q external of the cavity at temperatures from 4 K to room temperature. The results were then compared to the theory proposed by Reuter and Sondheimer. These measurements are a part of studies with the goal of reaching very high operational accelerating gradients in normal conducting rf structures.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW038
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW039	TM01 Mode Launcher for Use in High Brightness Photoguns	quadrupole, gun, impedance, cavity	491
	A.D. Cahill UCLA, Los Angeles, California, USA M. Dal Forno, V.A. Dolgashev SLAC, Menlo Park, California, USA
	Funding: DOE SCGSR and DOE/SU Contract DE-AC02-76-SF00515 Photo rf guns are a source of electron beams for X-ray FELs such as LCLS and European XFEL. In existing photoguns power is coupled into the cavity by waveguides through the cell walls, like LCLS, or through coaxial coupling, at the European XFEL. We are considering feeding a gun using a circular waveguide with the TM01 mode. To do that we need a mode launcher, a matched device that couples the rectangular TE01 mode waveguide to a TM01 mode in a circular waveguide. Use of the mode launcher reduces complexity of the gun cavity and increases flexibility of positioning the input waveguide relative to the gun body. Mode launchers have been successfully used at SLAC and elsewhere for X-band high gradient tests. Because the existing mode launchers were not built for high brightness guns, they have a significant quadrupole field component. High brightness rf guns have tight requirements on output beam properties, and this quadrupole component adversely affects the beam. We have designed a mode launcher free of this disadvantage. We present design considerations, methodology, and an example S-band mode launcher.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW039
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW040	Electron Beam Excitation of a Surface Wave in mm-Wave Open Accelerating Structures	detector, vacuum, experiment, simulation	494
	M. Dal Forno, G.B. Bowden, C.I. Clarke, V.A. Dolgashev, M.J. Hogan, D.J. McCormick, A. Novokhatski, B.D. O'Shea, S.G. Tantawi, S.P. Weathersby SLAC, Menlo Park, California, USA B. Spataro INFN/LNF, Frascati (Roma), Italy
	Funding: Work supported by the US DOE under contract DE-AC02-76SF00515. As part of research on the physics of rf breakdowns we performed experiments with high gradient traveling-wave mm-wave accelerating structures. The accelerating structures are open, composed of two identical halves separated by an adjustable gap. The electromagnetic fields are excited by an ultra-relativistic electron beam. We observed that a confined travelling-wave mode exists in half of the accelerating structure. The experiments were conducted at FACET facility at SLAC National Accelerator Laboratory. Depending on the gap width, the accelerating structure had beam-synchronous frequencies that vary from 90 to 140 GHz. When we opened the gap by more than half wavelength the synchronous wave remains trapped. Its behavior is consistent with the so called "surface wave". We characterized this beam-wave interaction by several methods: measurement of the radiated rf energy with the pyro-detector, measurement of the spectrum with an interferometer, measurement of the beam deflection by using the beam position monitors and profile monitor.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW040
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW041	Measurements of RF Breakdowns in Beam Driven mm-Wave Accelerating Structures	vacuum, experiment, detector, collider	497
	M. Dal Forno, G.B. Bowden, C.I. Clarke, V.A. Dolgashev, M.J. Hogan, D.J. McCormick, A. Novokhatski, S.G. Tantawi, S.P. Weathersby SLAC, Menlo Park, California, USA B. Spataro INFN/LNF, Frascati (Roma), Italy
	Funding: Work supported by the US DOE under contract DE-AC02-76SF00515 We studied the physics and properties of rf breakdowns in high gradient traveling-wave accelerating structures at 100 GHz. The structures are open, made of two halves with a gap in between. The rf fields were excited in the structure by an ultra-relativistic electron beam generated by the FACET facility at the SLAC National Accelerator Laboratory. We observed rf breakdowns generated in the presence of GV/m scale electric fields. We varied the rf fields excited by the FACET bunch by moving structure relative to the beam and by changing the gap between structure halves. Reliable breakdowns detectors allowed us to measure the rf breakdown rate at these different rf parameters. We measured radiated rf energy with a pyro-detector. When the beam was off-axis, we observed beam deflection in the beam position monitors and on the screen of a magnetic spectrometer. The measurements of the deflection allowed us to verify our calculation of the accelerating gradient.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW041
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW042	Multi-Dimensional RF Sources Design	klystron, cavity, space-charge, gun	501
	M. Dal Forno, A. Jensen, R.D. Ruth, S.G. Tantawi SLAC, Menlo Park, California, USA
	Funding: Work supported by the US DOE under contract DE-AC02-76SF00515. Vacuum electronic devices, such as rf sources for accelerator applications, must provide high rf power with high efficiency. To achieve these requirements, multi-beam klystron and sheet-beam klystron devices have been developed. Multi-beam klystrons, at high frequency employ separate output cavities; hence they have the disadvantage that combining all the rf pulses, generated by all the beams, is challenging. Sheet-beam klystrons have problems with instabilities and with space charge forces that makes the beam not naturally confined. We are proposing an alternative approach that reduces space charge problems, by adopting geometries in which the space charge forces are naturally balanced. An example is when the electron beam is generated by a central source (well) and the electron motion corresponds to the natural expansion of the electron cloud (three-dimensional device). In this paper we will present the design and challenges of a bi-dimensional rf source, a cylindrical klystron, composed by concentric pancake resonant cavities. In this case, space charge forces are naturally balanced in the azimuthal direction.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW042
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW044	Design of an RF Device to Study the Multipactor Phenomenon	cavity, simulation, multipactoring, experiment	507
	D. Amorim Grenoble-INP Phelma, Grenoble, France J.-M. De Conto, Y. Gómez Martínez LPSC, Grenoble Cedex, France
	Multipacting is a parasitic electron avalanche process that may occur in RF devices such as cavities or couplers. As it can be detrimental to the operation of these devices, the accelerator group at LPSC is currently designing a coaxial resonant cavity in order to study this phenomenon. In order to determine the measurable parameters on the cavity, calculations were performed and validated with numerical simulations. In a second time multipacting simulations were conducted to determine if the experiment will allow to observe multipacting.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW044
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMY001	Beam Dynamics Analysis for the Ultra-fast Kicker in Circular Cooler Ring of JLEIC	kicker, emittance, cavity, recirculation	510
	Y.L. Huang IMP/CAS, Lanzhou, People's Republic of China R.A. Rimmer, H. Wang, S. Wang JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. An ultra-fast kicker system consist of four quarter wavelength resonator based deflecting cavities was developed that simultaneously resonates at 10 subharmonic modes of the 476.3MHz bunch repetition frequency, thus every 10th bunch in the bunch train will experience a transverse kick while all the other bunches are undisturbed. This fast kicker is developed for the Energy Recovery Linac (ERL) based electron Circular Cooler Ring (CCR) in the proposed Jefferson Lab Electron Ion Collider (JLEIC, previously MEIC). The electron bunches can be reused 10-30 turns thus the beam current in the ERL can be reduced to 1/10 - 1/30 (150mA - 50mA) of the cooling bunch current (1.5A). In this paper, several methods to synthesis such a kicker waveform will be discussed with the comparison of beam dynamics tracking in Elegant.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY001
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMY003	Transient Beam Loading Effects in RF Systems in JLEIC	cavity, klystron, feedback, controls	518
	H. Wang, J. Guo, R.A. Rimmer, S. Wang JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The pulsed electron bunch trains generated from the Continuous Electron Beam Accelerator Facility (CEBAF) linac to inject into the proposed Jefferson Lab Electron Ion Collider (JLEIC) e-ring will produce transient beam loading effects in the Superconducting Radio Frequency (SRF) systems that, if not mitigated, could cause unacceptably large beam energy deviation in the injection capture, exceed the energy acceptance of CEBAF's recirculating arc. In the electron storage ring, the beam abort or ion clearing gaps or uneven bucket filling can cause large beam phase transients in the (S)RF cavity control systems and even beam loss due to Robinson instability. We have first analyzed the beam stability criteria in steady state and estimate the transient effect in Feedforward and Feedback RF controls. Initial analytical models for these effects are shown for the design of the JLEIC e-ring from 3GeV to 12GeV.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY003
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMY009	HOM Consideration of 704 MHz and 2.1 GHz Cavities for LEReC Linac	cavity, HOM, SRF, booster	528
	B. P. Xiao, I. Ben-Zvi, M. Blaskiewicz, J.M. Brennan, J.C. Brutus, A.V. Fedotov, H. Hahn, G.T. McIntyre, C. Pai, K.S. Smith, J.E. Tuozzolo, Q. Wu, T. Xin, W. Xu, A. Zaltsman BNL, Upton, Long Island, New York, USA S.A. Belomestnykh Fermilab, Batavia, Illinois, USA S.A. Belomestnykh, I. Ben-Zvi Stony Brook University, Stony Brook, USA V. Veshcherevich Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 and by National Energy Research Scientific Computing Center under contract No. DE-AC02-05CH11231 by US DOE. To improve RHIC luminosity for heavy ion beam energies below 10 GeV/nucleon, the Low Energy RHIC electron Cooler (LEReC) is currently under development at BNL. The Linac of LEReC is designed to deliver 2 MV to 5 MV electron beam, with rms dp/p less than 5·10^-4. The HOM in this Linac is carefully studied to ensure this specification.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY009
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMY014	Design Study of RF Section and Cavities for Cepc 650 MHz Klystron	klystron, cavity, simulation, bunching	543
	O. Xiao Institute of High Energy Physics (IHEP), People's Republic of China D.D. Dong, S. Fukuda, Z.J. Lu, G. Pei, S.C. Wang, .. Zaib-un-Nisa, Z.S. Zhou IHEP, Beijing, People's Republic of China S. Fukuda KEK, Ibaraki, Japan
	An 800 kW CW klystron operating at 650 MHz is de-veloped for CEPC at Institute of High Energy Physics in China. The conceptual design has been finished and the main parameters are presented in this paper. A 1D large signal disk model code, AJDISK, has been used to design and optimize klystron RF section parameters. In addition, the RF cavities have been designed using SUPERFISH, HFSS and CST.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY014
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMY015	Design Study of Electron Gun for CEPC 650 MHz Klystron	gun, klystron, cathode, simulation	546
	.. Zaib-un-Nisa, D.D. Dong, Z.J. Lu, G. Pei, S.C. Wang, O. Xiao, Z.S. Zhou IHEP, People's Republic of China S. Fukuda KEK, Ibaraki, Japan
	This paper presents the design and simulation of an electron gun for 800 kW CW klystron of which frequency is 650 MHz for CEPC project. An electron gun with a modulating anode is designed using DGUN software. The uniform beam trajectories, with a beam perveance of 0.64μA/V 3/2 are simulated. We employed a Ba-dispenser cathode of radius 35 mm with Φ10 hole at the center and obtained a current density on cathode less than 0.45 A/cm². The beam trajectories were also simulated over whole tube length with a magnetic field of 207 Gauss. Expecting functions using the modulating anode gun are also described. Proposed beam tester and whole CEPC klystron layout are also shown in this paper.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY015
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMY026	Development of an X-Band Linearizer System for PAL-XFEL	klystron, LLRF, acceleration, wakefield	554
	H. Heo, J. Hu, H.-S. Kang, K.H. Kim, S.H. Kim, H.-S. Lee, B.G. Oh, S.S. Park, Y.J. Park, Y.J. Suh PAL, Pohang, Kyungbuk, Republic of Korea
	We developed an X-band RF system for the linear bunch compression in the PAL-XFEL. We installed a SLAC X-band accelerating structure on a precise mover stage and applied RF power by using a SLAC XL-4 11.424 GHz klystron driven by an inverter charging type modulator. We are developing a solid state amplifier controlled by an X-band LLRF system instead of using a TWTA as a driving RF source for the klystron. We present and discuss the recent test results of the system.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY026
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMY033	Effect of Bandwidth of Low Level Radio Frequency System on the Instability of an Electron Beam	feedback, LLRF, cavity, synchrotron	570
	Z.K. Liu, L.-H. Chang, M.H. Chang, L.J. Chen, PY. Chen, F.-T. Chung, M.-C. Lin, C.H. Lo, C.L. Tsai, M.H. Tsai, Ch. Wang, M.-S. Yeh, T.-C. Yu NSRRC, Hsinchu, Taiwan
	The analog Low Level Radio Frequency (LLRF) system is used at Taiwan Photon Source (TPS) RF system. It is composed of three feedback loops to control the amplitude and phase of accelerating field and the frequency of RF cavity. Instability of electron beam and accelerating field due to the bandwidth of LLRF system were observed during the TPS commissioning. This effect was studied and the results will be presented in this paper.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY033
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMY034	The Distributed Bunch Amplifier	network, coupling, focusing, distributed	573
	M.A. Franzi, A. Jensen, S.G. Tantawi, F. Toufexis, A.R. Vrielink SLAC, Menlo Park, California, USA
	The Distributed Bunch Amplifier (DBA) is a high efficiency RF source that utilizes a phase locked deflecting cavity and output circuit to produce a synchronous beam-wave interaction. The DBA improves on the design of previous embodiments of this technology, such as the Gyrocon, by implementing a modern decoupled output circuit design and conical PPM beam focusing array in order to scale to higher frequencies and efficiency than previously demonstrated. Presented is a proof-of-concept S-band, 2.856 GHz, device operating with a 60 kV, 8 Amp, electron beam. Each stage of the three-cavity decoupled output circuit is optimized based on complex amplitude and shunt impedance to achieve an electronic efficiency of greater than 90%. Initial numerical analysis of this design indicates that an overall operating efficiency of greater than 70% is feasible. Detailed simulated results of the S-band model and designs to scale this technology to higher power and frequency will be discussed. Budker, G. I., et al. "The Gyrocon: An Efficient Relativistic High Power VHF Generator." Part. Accel. 10 (1979): 41-59.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY034
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMY035	Theoretical Analysis and Simulation of a Compact Frequency Multiplier for High Power Millimeter and Terahertz Sources	cavity, cathode, coupling, space-charge	576
	A.R. Vrielink, S.G. Tantawi, F. Toufexis SLAC, Menlo Park, California, USA
	As the demands on accelerating gradients and the temporal resolution of beam diagnostics and manipulation schemes grow, millimeter-wave and terahertz (THz) accelerator structures may present a natural solution. The recent advent of a radiofrequency undulator and the development of a 0.45 THz accelerator demonstrate growing interest in this frequency regime; however, growth in this area is limited by the lack of efficient, compact high power sources. We present a novel vacuum electronic device featuring an interaction between a radially bunched electron beam and azimuthally traveling waves. The use of an inward traveling radial sheet beam mitigates space charge effects at the low operating energy of 10-30 keV and allows for a high input beam current of approximately 0.5-10 A. Based on preliminary calculations, these devices could operate from 50 GHz to 250 GHz with tens of kiloWatts of output power, while the expected efficiency would scale from 60% at 80 GHz to 15% at 230 GHz. Here we present the underlying theory, possible structure design, and preliminary results from analytical calculations and simulation. Tantawi, S. et al. Phys. Rev. Lett. 112, 164802 (April, 2014) Nanni, E. et al. Nat. Commun. 6, 8486 (October, 2015)
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY035
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMY036	High-harmonic mm-Wave Frequency Multiplication using a Gyrocon-like Device	cavity, coupling, vacuum, plasma	579
	F. Toufexis, V.A. Dolgashev, M.V. Fazio, A. Jensen, S.G. Tantawi, A.R. Vrielink SLAC, Menlo Park, California, USA P. Borchard Dymenso LLC, San Francisco, USA
	Funding: This project was funded by U.S. Department of Energy under Contract No. DE-AC02-76SF00515, and the National Science Foundation. Traditional linear interaction RF sources, such as Klystrons and Traveling Wave Tubes, fail to produce significant power levels at millimeter wavelengths. This is because their critical dimensions are small compared to the wavelength, and the output power scales as the square of the wavelength. We present a vacuum tube technology, where the device size is inherently larger than the operating wavelength. We designed a low–voltage mm–wave source, with an output interaction circuit based on a spherical sector cavity. This device was configured as a phased-locked frequency multiplier. We report the design and cold test results of a proof-of-principle fifth harmonic frequency multiplier with an output frequency of 57.12 GHz.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY036
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMY037	GaN Class-F Power Amplifier for Klystron Replacement	klystron, vacuum, operation, controls	583
	A.V. Smirnov RadiaBeam Systems, Santa Monica, California, USA R.B. Agustsson, S. Boucher, D.I. Gavryushkin, J.J. Hartzell, K.J. Hoyt, A.Y. Murokh, T.J. Villabona RadiaBeam, Santa Monica, California, USA
	Funding: This work was supported by the U.S. Department of Energy (award No. DE-SC0013136) The vacuum-tube-based RF amplifiers are relatively inefficient and becoming obsolete as the RF world has been progressively converting to solid state technology. Currently, the JLAB upgrade program requires 340 amplifiers capable of 8 kW CW at 1497 MHz while operating at more than 55-60% efficiency to replace their klystrons. Here we explore the possibility of a klystron replacement employing high electron mobility packaged GaN transistors applied in an array of Class-F amplifiers. The inputs and outputs of the many modules needed to make a complete amplifier are connected via precise, in-phase, low-loss, broadband, combiners-dividers. We describe early prototypes of the amplifiers as well as the combiners-dividers and discuss the design features and challenges of such a scheme. This approach can be applied to other national facilities and also for replacement of the klystrons in Middle Energy Electron-Ion Collider which requires about 1.8 MW CW power in total to be produced at 952.6 MHz frequency including 2x12.5 kW power for "crabbing" and 0.53 MW for electron cooling.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY037
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOR005	Longitudinal Wakefields in the Undulator Section of SXFEL User Facility	undulator, FEL, wakefield, vacuum	595
	M. Song, H.X. Deng, C. Feng, D. Huang, B. Liu, D. Wang SINAP, Shanghai, People's Republic of China
	Shanghai soft x-ray free electron laser (SXFEL) user facility based on multi-stage seeded-FEL and self-amplified spontaneous emission (SASE) is recently proposed, which is aiming at generating 4-2nm fully-coherent, high-brightness FEL pulse. In this paper, the wakefields arise from the resistive wall and surface roughness in the vacuum chamber is obtained by theoretical models. And the computations of geometric wakefields are carried out using ABCI. According to the tracked beam profile, the overall wakefields in the undulator section of SXFEL user facility are presented. K. Bane, G. Stupakov, SLAC-PUB-15951, May 2014. ** ABCI website: http://abci.kek.jp/abci.htm
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR005
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOR022	Beam Dynamics Observations of the 2015 High Intensity Scrubbing Runs at the Cern Sps	operation, octupole, injection, emittance	648
	H. Bartosik, G. Iadarola, K.S.B. Li, L. Mether, A. Romano, G. Rumolo, M. Schenk CERN, Geneva, Switzerland
	Beam quality degradation caused by e-cloud effects has been identified as one of the main performance limitations for high intensity LHC beams with 25 ns bunch spacing in the SPS. In view of the beam parameters targeted with the LHC injectors upgrade (LIU) project, about two weeks of SPS machine time in 2015 were devoted to dedicated scrubbing runs with high intensity LHC 25 ns and dedicated 'doublet' beams in order to study the achievable reduction of e-cloud effects and quantify the consequent beam performance improvements. This paper describes the main observations concerning the coherent instabilities and beam dynamics limitations encountered as well as a detailed characterisation of the performance reach with the highest beam intensity presently available from the pre-injectors.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR022
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOR026	Measurement of the Energy Distribution Function of Electrons Generated by Radio-frequency Induced Multipacting in a Beam Pipe	multipactoring, gun, radio-frequency, diagnostics	664
	M. Van Gompel, F. Caspers, P. Costa Pinto, R. Leber, A. Romano, R. Salemme, M. Taborelli CERN, Geneva, Switzerland
	The development of Electron Multipacting (EM) in high intensity particle accelerators depends, amongst others, on the Secondary Electron Yield (SEY) of surfaces facing the beam. In-situ studies of electron clouds in particle accelerators must cope with operation schedule and other technical constrains. To overcome these difficulties, CERN implemented a Multipactor test bench, where EM is generated by Radio-Frequency (RF), using the beam pipes as a coaxial resonators. This tool was already successfully used to assess the effectiveness of low SEY carbon coatings on dipoles of the SPS at CERN and to study the conditioning dynamics of beam pipes. In this paper we present the development of an in-house built Retarding Field Energy Analyser (RFEA) to measure the Electrons Energy Distribution Function (EEDF) in the Multipactor test bench. The design of the electrodes was based on simulations in order to optimize sensitivity and energy resolution. The setup was tested with an electron gun at different energies before insertion in the Multipactor test bench. The evolution of the EEDF is measured at different RF powers. Feasibility to perform measurements in the machine is discussed.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR026
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOR033	Simulations of Dark Current from the BERLinPro Booster Module	cavity, cathode, booster, simulation	671
	M. McAteer, M. Abo-Bakr, B.C. Kuske, A. Neumann HZB, Berlin, Germany
	Funding: Work supported by the German Bundesministerium f\"ur Bildung und Forschung, Land Berlin and grants of Helmholtz Association Dark current emitted from the surface of high-field RF cavities can contribute to radiation levels and cryo budget and can cause damage to sensitive accelerator components such as the photocathode. The superconducting niobium cavities in the booster module of BERLinPro will have surface fields strong enough to produce significant dark current from field emission, so simulations were made using Astra to track the propagation of emitted electrons from the surfaces of the cavities to examine the effects of dark current in the BERLinPro injector. Results of these simulations, including optimization of the layout to reduce propagation of electrons to the cathode and an estimation of power from dark current deposited throughout the injector, are presented.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR033
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOR034	Numerical Space-Charge Compensation Studies and Comparison of Different Models	simulation, proton, space-charge, ion	674
	D. Noll, M. Droba, O. Meusel, U. Ratzinger, K. Schulte, C. Wiesner IAP, Frankfurt am Main, Germany
	The design of many Low-Energy Beam Transport sections relies on the presence of space-charge compensation by particles of opposing charge. To improve understanding of the processes involved in the built-up and steady-state, simulations using the Particle-in-Cell code bender were made. We will present the influence of various system parameters on the results. Furthermore, the electron velocity distribution was found to be approximately thermal. The spatial distribution can then be found by solving the Poisson-Boltzmann equation. Such a model for the electron distribution was implemented in a 2D PIC code and applied to typical beam transport situations. We will present results in comparison to the 3D simulations.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR034
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOR039	Measurement of Beam Phase at FLASH using HOMs in Accelerating Cavities	HOM, cavity, simulation, coupling	686
	L. Shi, R.M. Jones UMAN, Manchester, United Kingdom N. Baboi, L. Shi DESY, Hamburg, Germany N.Y. Joshi University of Manchester, Manchester, United Kingdom
	The beam phase relative to the accelerating field is of vital importance for the quality of photon beams produced in modern Free Electron Lasers based on superconducting (SC) cavities. Normally, the phase is determined by detecting the transient field induced by the beam. In this way the phase of each cavity is checked and adjusted typically every few months. In this paper, we present another means of beam phase determination, based on higher order modes (HOMs) excited in the 2nd monopole band by the beam inside the SC cavities. A circuit model of this HOM band is also presented. Various effects on the resolution have been studied. Circuit model simulations indicate the resolution is strongly dependent on the signal to noise ratio. Preliminary experimental results, based on a broadband setup, reveal an approximately 0.1o RMS resolution. These are in good agreement with simulation results. The work will pave the way for a dedicated system of beam phase monitoring, which is under development for the European XFEL. This will be the first implementation of a dedicated beam phase monitor, based on beam-excited HOMs in accelerating cavities.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR039
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOR047	Numerical and Experimental Substantiation of the Ion Density Beam Transfer Function Measurements	ion, betatron, space-charge, accumulation	698
	D. Sauerland, W. Hillert ELSA, Bonn, Germany
	Funding: Funded by the BMBF, Germany under grant 05K13PDA In the ELSA stretcher ring electrons are accelerated to a beam energy of 3.2 GeV utilizing a fast energy ramp of 6 GeV/s. Ions being generated by collision with the residual gas molecules accumulate inside the beam potential, causing incoherent tune shifts and coherent beam instabilities. Since the ion induced incoherent tune shift rises linearly with the beam neutralisation, it offers a suitable approach for evaluating the efficiency of several ion clearing measures. It was indirectly measured using a new experimental approach: By measuring the beam transfer function using a broadband transversal kicker, one was able to perceive a shift and broadening of the tune peak. Both effects could be adequately parameterized providing a quantity proportional to the incoherent tune shift and thus the average neutralisation. The impact of incoherent effects to the coherent electron beam response during the measurement has not been subject to intensive theoretical attention yet. This leaves the obtained quantity unscaled. Here new numerical simulations and experimental investigations will be presented in order to further substantiate the results of this new method.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR047
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW003	RF Phase Jitter Consideration in Bunch Compression	klystron, simulation, linac, FEL	704
	T.K. Charles, D.M. Paganin Monash University, Faculty of Science, Clayton, Victoria, Australia M.J. Boland, R.T. Dowd SLSA, Clayton, Australia
	Error propagation of RF phase jitter is analysed for various linac layout configurations and the sensitivity of the compression ratio due to RF phase jitter is analysed. Multiple sources of jitter have the opportunity to destructively interfere, and (perhaps counter intuitively) found to not add in quadrature. Results are compared to Elegant simulations.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW003
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW004	Electron Trajectory Caustic Formation Resulting in Current Horns present in Bunch Compression	FEL, linac, wakefield, simulation	708
	T.K. Charles, D.M. Paganin Monash University, Faculty of Science, Clayton, Victoria, Australia M.J. Boland, R.T. Dowd SLSA, Clayton, Australia
	Current horns are ubiquitous in Free Electron Laser (FEL) bunch compression. In this paper, we analyse the formation of these current spikes and identify the cause as caustic formation in the electron trajectories. We also present a possible solution to avoid or mitigate the current horns from developing through using optical linearization.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW004
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW005	First Electron Beam Measurements on COXINEL	laser, undulator, plasma, quadrupole	712
	T. André, I.A. Andriyash, C. Basset, C. Benabderrahmane, P. Berteaud, S. Bonnin, F. Bouvet, F. Briquez, L. Cassinari, L. Chapuis, M.-E. Couprie, D. Dennetière, Y. Dietrich, M. Diop, J.P. Duval, M.E. El Ajjouri, T.K. El Ajjouri, P. Gattoni, C. Herbeaux, N. Hubert, M. Khojoyan, M. Labat, N. Leclercq, A. Lestrade, A. Loulergue, O. Marcouillé, F. Marteau, P. Pierrot, F. Polack, F. Ribeiro, J.P. Ricaud, P. Rommeluère, M. Sebdaoui, K.T. Tavakoli, M.-A. Tordeux, M. Valléau, J. Vétéran, D. Zerbib, C. de Olivera SOLEIL, Gif-sur-Yvette, France S. Bielawski, C. Evain, C. Szwaj PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France J. Gautier, E. Guillaume, G. Lambert, B. Mahieu, V. Malka, A. Rousse, K. Ta Phuoc, C. Thaury LOA, Palaiseau, France E. Roussel Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	The ERC grant COXINEL aims at demonstrating experimentally Free Electron Laser (FEL) amplification with electrons generated by laser plasma acceleration (LPA). Because of the still limited electron beam performance (especially energy spread and divergence) in view of the FEL requirements, the electron beam transfer line has been specifically designed with adequate diagnostics and strong focusing variable strength permanent magnet quadrupoles, an energy de-mixing chicane and second set of quadrupoles for further dedicated focusing in the FEL interaction region, in a U20 in-vacuum undulator, enabling to operate at 200 nm with a 180 MeV electron beam. The first observation and transport of electrons in the COXINEL line is presented here.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW005
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW006	Planning and Controlling of the Cold Accelerator Sections Installation in XFEL	status, laser, free-electron-laser, vacuum	716
	M. Bousonville, S. Choroba, F. Eints DESY, Hamburg, Germany
	The installation of the main linear accelerator in the 2 km European XFEL (X-Ray Free-Electron Laser) tunnel is currently under way. The accelerator consists of nine so-called cryo-strings. A typical cryo-string comprises 12 accelerator modules, which will be fed by three RF stations. Furthermore, the installation of electronic racks, cables, power and water supply etc. takes place. To enable a most effective installation of the accelerator components, planning and controlling methods, which had first been developed for the RF system work package, were adapted for the entire main linear accelerator. As a first step, a process plan was developed in cooperation with the work package leaders. On the basis of this plan, the installation process is promoted by several measures: The status of the installation is precisely registered by weekly queries which enable monitoring of the progress and feedback to everyone involved. With this information at hand, the installation process can be controlled and plan deviations can be corrected. Furthermore, the experience gained at one cryo-string is used to optimise the plan for the next cryo-string installation.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW006
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW009	Studies of Harmonic Lasing Self-seeded FEL at FLASH2	undulator, FEL, simulation, radiation	725
	E. Schneidmiller, M.V. Yurkov DESY, Hamburg, Germany
	A concept of the Harmonic Lasing Self-Seeded (HLSS) FEL was proposed in,. A gap-tunable undulator is divided into two parts such that the first part is tuned to a sub-harmonic of the second part. Harmonic lasing occurs in the exponential gain regime in the first part of the undulator, also the fundamental stays well below saturation. In the second part of the undulator the fundamental mode is resonant to the wavelength, previously amplified as the harmonic. The amplification process proceeds in the fundamental mode up to saturation. In this case the bandwidth is reduced by a significant factor depending on harmonic number but the saturation power is still as high as in the reference case of lasing at the fundamental in the whole undulator, i.e. the spectral brightness increases. Application of the post-saturation tapering would allow to generate higher peak power than in SASE mode due to an improved longitudinal coherence. We present feasibility study of the application of the HLSS FEL scheme at FLASH2 and show that it allows to achieve a higher power and a smaller bandwidth than in a standard SASE regime. First experimental tests are eventually discussed. E.A. Schneidmiller and M.V. Yurkov, Phys. Rev. ST-AB 15 (2012) 080702 ** E.A. Schneidmiller and M.V. Yurkov, "Harmonic Lasing Self-Seeded FEL", Proc. of FEL2013 Conf., New York, USA
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW009
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOXAA01

International Linear Collider, Latest Status towards Realization

collider, linear-collider, superconducting-RF, cryomodule

1

S. Komamiya
ICEPP, Tokyo, Japan

This presentation describes the International Linear Collider (ILC), an e⁺ and e^- collider based on the superconducting linear accelerator with a center of mass energy of 500 GeV in the first stage, upgradeable to 1 TeV. According to the statement of the Science Council of Japan, MEXT (Ministry of Education, Science, and Sports) and the Japanese government have investigated the feasibility of the ILC project, not only from the scientific view, but also the political, economical, and sociological points of view. The latest status of the project will be presented.

Slides MOXAA01 [12.564 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOXAA01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOYBA01

Limits and Possibilities of Laser Wakefield Accelerators

laser, plasma, coupling, focusing

16

W. Leemans
LBNL, Berkeley, California, USA

This presentation provides an outlook into the future of laser-driven plasma wakefield accelerators. What has been achieved, what more is possible and what are the limits.

Slides MOYBA01 [43.465 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOYBA01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOOCA03

Thyratron Replacement

operation, klystron, network, linear-collider

45

I. Roth, M.P.J. Gaudreau, M.K. Kempkes
Diversified Technologies, Inc., Bedford, Massachusetts, USA

Funding: Work supported by DOE under contract DE-SC0011292
Semiconductor thyristors have long been used as a replacement for thyratrons in low power or long pulse RF systems. To date, however, such thyristor assemblies have not demonstrated the reliability needed for installation in short pulse, high peak power RF stations used with many pulsed electron accelerators. The fast rising current in a thyristor tends to be carried in a small region, rather than across the whole device, and this localized current concentration can cause a short circuit failure. An alternate solid-state device, the insulated-gate bipolar transistor (IGBT), can readily operate at the speed needed for the accelerator, but commercial IGBTs cannot handle the voltage and current required. It is, however, possible to assemble these devices in arrays to reach the required performance levels without sacrificing their inherent speed. Diversified Technologies, Inc. (DTI) has patented and refined the technology required to build these arrays of series-parallel connected switches. DTI is currently developing an affordable, reliable, form-fit-function replacement for the klystron modulator thyratrons at SLAC capable of pulsing at 360 kV, 420 A, 6 μs, and 120 Hz.

Slides MOOCA03 [2.636 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOOCA03

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB003

Comparison of Coherent Smith-Purcell Radiation and Coherent Transition Radiation

radiation, laser, free-electron-laser, simulation

72

V. Khodnevych, N. Delerue
LAL, Orsay, France
O.A. Bezshyyko, V. Khodnevych
National Taras Shevchenko University of Kyiv, The Faculty of Physics, Kyiv, Ukraine

Funding: The authors are grateful for the funding received from the French ANR (contract ANR-12-JS05-0003-01) and the IDEATE International Associated Laboratory (LIA) between France and Ukraine.
Smith-Purcell radiation and Transition Radiation are two radiative phenomenon that occur in charged particles accelerators. For both the emission can be significantly enhanced with sufficiently short pulses and both can be used to measure the form factor of the pulse. We compare the yield of these phenomenon in different configurations and look at their application as bunch length monitors, including background filtering and rejection. We apply these calculations to the specific case of the CLIO Free Electron laser.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB003

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB004

Comparison of the Smith-purcell Radiation Yield for Different Models

radiation, simulation, experiment, detector

75

M.S. Malovytsia, N. Delerue
LAL, Orsay, France
M.S. Malovytsia
KhNU, Kharkov, Ukraine

Funding: The authors are grateful for the funding received from the French ANR (contract ANR-12-JS05-0003-01) and the IDEATE International Associated Laboratory (LIA) France-Ukraine.
Smith-Purcell radiation is used in several applications including the measurement of the longitudinal profile of electron bunches. A correct reconstruction of such profile requires a good understanding of the underlying model. We have compared the leading models of Smith-Purcell radiation and shown that they are in agreement within the experimental errors.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB004

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB005

Study of Short Bunches at the Free Electron Laser CLIO

radiation, cavity, gun, simulation

78

V. Khodnevych, N. Delerue, S. Jenzer
LAL, Orsay, France
J.P. Berthet, F. Glotin, J.-M. Ortega, R. Prazeres
CLIO/ELISE/LCP, Orsay, France
V. Khodnevych
National Taras Shevchenko University of Kyiv, The Faculty of Physics, Kyiv, Ukraine

Funding: The authors are grateful for the funding received from the French ANR (contract ANR-12-JS05-0003-01).
CLIO is a Free Electron Laser based on a thermionic electron gun. In its normal operating mode it delivers electron 8 pulses but studies are ongoing to shorten the pulses to about 1 ps. We report on simulations showing how the pulse can be shortened and the expected signal yield from several bunch length diagnostics (Coherent Transition Radiation, Coherent Smith Purcell Radiation).

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB005

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB007

Diamond Sensor Resolution in Simultaneous Detection of 1,2,3 Electrons at the PHIL Photoinjector Facility at LAL

detector, experiment, simulation, target

84

V. Kubytskyi, P. Bambade, S. Barsuk
LAL, Orsay, France
O.A. Bezshyyko, V. Krylov, V. Rodin
National Taras Shevchenko University of Kyiv, The Faculty of Physics, Kyiv, Ukraine

In this paper, we present experimental and numerical studies of the signals from the Poisson-like distributions resulting from electrons incident on a diamond sensor placed near the exit of the PHIL photoinjector facility at LAL. The experiments were performed at the newly commissioned Low Energy Electron TECHnology (LEETECH) platform at PHIL. Bunches of 10x9 electrons are first generated and accelerated to 3.5 MeV by PHIL. The electrons are then filtered in LEETECH by a system of collimators, using a dipole magnet for momentum selection. The diamond sensor is located immediately after the output collimator to collect electrons in the range 2.5-3 MeV. We show that with standard scCVD diamonds of 500 micrometers thickness, the energy losses from the first three MIP (minimum ionizing particle) electrons are clearly resolved. We did not observe distinguishable peaks in cases when a significant fraction of the incident electrons had energies below a MIP. The described technique can be used as complementary approach for calibration of diamond detectors as well as to diagnose and help control accelerated beams in a regime down to a few particles.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB007

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB009

Electron Beam Probe for the Bunch Length Measurements at BERLinPro

diagnostics, simulation, gun, operation

92

D. Malyutin, A.N. Matveenko
HZB, Berlin, Germany

For the successful operation of various accelerator facilities a detailed bunch characterization is required. A complete description can be achieved using various diagnostic systems installed along an accelerator beamline. Ideally the diagnostic should be able to measure parameters of a single bunch in a non-destructive manner. For bunch length measurements this results in a complicated task especially for bunch duration below 1 ps. One of the possible solutions is a diagnostic based on the interaction of a low energy electron beam with electro-magnetic fields of the relativistic bunch. The bunch length can be readily deduced from the resulting scatter. In this paper bunch length measurement technique based on a low energy electron beam is introduced. Results of numerical simulations of measurements are presented. A possible setup of such diagnostic system for BERLinPro facility is proposed.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB009

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB010

Compton Polarimetry at ELSA - Beamline and Detector Optimization

photon, polarization, laser, detector

95

R. Koop, W. Hillert, M.T. Switka
ELSA, Bonn, Germany

Funding: Work supported by DFG within CRC TRR16
The Electron Stretcher Facility ELSA provides a polarized electron beam with energies of 0.5 - 3.2 GeV for double polarization hadron physics experiments. Monitoring the vertical electron polarization by Compton polarimetry in the stretcher ring has several advantages over the established polarization measurement by Moeller polarimetry. The Compton polarimeter setup presented consists of a 40 W cw disk laser featuring two polarized photon beams colliding head-on with the stored electron beam in ELSA. A silicon strip detector measures the vertical intensity profile of the backscattered photons. The reversal of handedness of the laser beam's circular polarization results in a polarization dependent vertical shift of this profile. From a calibration using time dependent polarization build-up due to the Sokolov-Ternov effect, the polarization degree of the electron beam can be extracted. After recent laser repairs as well as beamline and detector modifications, first measurement attempts of the electron's polarization degree were conducted. The performance of the beamline and first measurements are presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB010

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB012

A High-Energy-Scrapersystem for the S-DALINAC Extraction - Design and Installation

extraction, linac, vacuum, dipole

101

L.E. Jürgensen, T. Bahlo, C. Burandt, T. Kürzeder, N. Pietralla, S. Weih, J. Wissmann
TU Darmstadt, Darmstadt, Germany
F. Hug
IKP, Mainz, Germany

Funding: *Funded by Deutsche Forschungsgemeinschaft under grant No. SFB 634
The superconducting Darmstadt linear electron accelerator (S-DALINAC) of the Institute for Nuclear Physics at Technische Universität Darmstadt delivers electron beams in cw-mode with energies up to 130 MeV. The accelerator consists of a 10-MeV injector and a 30-MeV main linac where superconducting 3-GHz microwave cavities are operated at a temperature of 2 K for beam acceleration. With three recirculation beamlines the main linac can be used up to four times. To improve the energy spread and the energy stability of the beam a new scrapersystem has been developed and installed. It changes the extraction beam line into a dispersion-conserving chicane consisting of four dipole magnets and three scrapers. The system includes scraping of x- and y-halo in two positions as well as improving and stabilizing energy spread on a dispersive part. We will present the design of the system and report on its installation into the accelerator complex.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB012

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB013

Time-resolved Spectral Observation of Coherent THz Pulses at DELTA

radiation, laser, detector, simulation

105

C. Mai, F.H. Bahnsen, M. Bolsinger, F. Götz, S. Hilbrich, M. Höner, M.A. Jebramcik, S. Khan, N.M. Lockmann, A. Meyer auf der Heide, R. Molo, R. Niemczyk, G. Shayeganrad, M. Suski, P. Ungelenk, D. Zimmermann
DELTA, Dortmund, Germany

Funding: Work supported by the BMBF (05K13PEC), the DFG (INST 212/236-1) and the state of NRW.
Coherent THz pulses induced by a laser-electron interac- tion are routinely produced and observed at DELTA, a 1.5- GeV synchrotron light source operated by the TU Dortmund University. At a dedicated THz beamline, measurements using a Fourier-transform spectrometer have been performed between 1 THz and 7 THz. Recently, an ultrafast Schottky- diode detector and a novel polarizing Fourier-transform spec- trometer were installed, which enable turn-by-turn-resolved spectral measurements in the frequency range below 1 THz. The commissioning results of the new spectrometer and simulations are presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB013

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB015

Technical Design Considerations About the SINBAD-ARES Linac

linac, laser, gun, acceleration

112

B. Marchetti, R.W. Aßmann, U. Dorda, K. Flöttmann, M. Hachmann, I. Hartl, J. Herrmann, M. Hüning, G. Kube, F. Ludwig, F. Mayet, M. Pelzer, I. Peperkorn, S. Pfeiffer, H. Schlarb, M. Titberidze, G. Vashchenko, M.K. Weikum, L. Winkelmann, K. Wittenburg, J. Zhu
DESY, Hamburg, Germany
R. Rossmanith
KIT, Karlsruhe, Germany

The SINBAD facility (Short and INnovative Bunches and Accelerators at Desy) is foreseen to host various experiments in the field of production of ultra-short electron bunches and novel high gradient acceleration technique. The SINBAD linac, also called ARES (Accelerator Research experiment at SINBAD), will be a conventional S-band linear RF accelerator allowing the production of low charge (0.5 pC - few pC) ultra-short electron bunches (FWHM, length <= 1 fs - few fs) having 100 MeV energy. In this paper we present the current status of the technical design considerations, motivate the foreseen diagnostics for the RF gun commissioning and present examples of foreseen applications.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB015

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB017

Design Issues for the Optical Transition Radiation Screens for theELI-NP Compton Gamma Source

radiation, simulation, linac, laser

118

M. Marongiu, A. Giribono, A. Mostacci, V. Pettinacci
INFN-Roma, Roma, Italy
D. Alesini, E. Chiadroni, F. Cioeta, G. Di Pirro, V.L. Lollo, L. Pellegrino, V. Shpakov, A. Stella, C. Vaccarezza, A. Variola
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
INFN-Roma II, Roma, Italy
L. Palumbo
University of Rome La Sapienza, Rome, Italy

A high brightness electron LINAC is being built in the Compton Gamma Source at the ELI Nuclear Physics facility in Romania. To achieve the design luminosity, a train of 32, 16 ns spaced, bunches with a nominal charge of 250 pC will collide with the laser beam in the interaction point. Electron beam spot size is measured with optical transition radiation profile monitors. In order to measure the beam properties along the train, the screens must sustain the thermal stress due to the energy deposited by the bunches; moreover the optical radiation detecting system must have the necessary accuracy and resolution. This paper deals with the analytical studies as well as numerical simulations to investigate the thermal behaviour of the screens impinged by the nominal bunch; the design and the performance of the optical detection line is discussed as well.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB017

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB018

Metrological Characterization of the Bunch Length Measurement by Means of a RF Deflector at the ELI-NP Compton Gamma source

linac, simulation, laser, brightness

122

L. Sabato
U. Sannio, Benevento, Italy
D. Alesini, C. Vaccarezza, A. Variola
INFN/LNF, Frascati (Roma), Italy
P. Arpaia
CERN, Geneva, Switzerland
P. Arpaia, A. Liccardo
Naples University Federico II, Science and Technology Pole, Napoli, Italy
A. Giribono
University of Rome La Sapienza, Rome, Italy
A. Mostacci, L. Palumbo
Rome University La Sapienza, Roma, Italy
L. Sabato
INFN-Napoli, Napoli, Italy

Bunch length measurement in linac can be carried out using a RF deflector, which provides a transverse kick to the beam. The transverse beam size on a screen, placed after the RF deflector, represents the bunch length. In this paper, the metrological characterization of the bunch length measurement technique is proposed. The uncertainty and the systematic errors are estimated by means of a sensitivity analysis to the measurement parameters. The proposed approach has been validated through simulation by means of ELEGANT code on the parameters interesting for the electron linac of the Compton source at the Extreme Light Infrastructure - Nuclear Physics (ELI-NP).

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB018

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB019

Quadrupole Scan Emittance Measurements for the ELI-NP Compton Gamma Source

emittance, quadrupole, linac, laser

126

A.R. Rossi, A. Bacci, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano, Italy
E. Chiadroni, C. Vaccarezza, A. Variola
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
C. Curatolo, I. Drebot
Universita' degli Studi di Milano e INFN, Milano, Italy
A. Giribono, A. Mostacci
University of Rome La Sapienza, Rome, Italy
V. Petrillo, M. Rossetti Conti
Universita' degli Studi di Milano & INFN, Milano, Italy

The high brightness electron LINAC of the Compton Gamma Source at the ELI Nuclear Physics facility in Romania is accelerating a train of 32 bunches with a nominal charge of 250 pC and nominal spacing of 16 ns. To achieve the design gamma flux, all the bunches along the train must have the designed Twiss parameters. Beam sizes are measured with optical transition radiation monitors, allowing a quadrupole scan for Twiss parameters measurements. Since focusing the whole bunch train on the screen may lead to permanent screen damage, we investigated non-conventional scans such as scans around a maximum of the beam size or scans with a controlled minimum spot size. This paper discusses the implementation issues of such a technique in the actual machine layout.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB024

Electron Cloud Measurements at J-PARC Main Ring

detector, vacuum, proton, extraction

137

B. Yee-Rendón, H. Kuboki, R. Muto, K. Satou, M. Tomizawa, T. Toyama, M. Uota
KEK, Ibaraki, Japan

Electron cloud instability is presented in most of the high intensity proton rings. During the Slow beam extraction (SX) mode at Main Ring of J-PARC, signals related with its formation were observed. An electron cloud detector is installed downstream of the ElectroStatic Septum (ESS), to measure the electron signal. Additionally, scintillation detector with photomultiplier, a proportional counter and photo-diode were set closely to the electron cloud detector to observe the beam lost. This paper presents the measurements of the electron cloud and some of the conditions which support its creation, for instance the signal of lost particle from the beam loss monitors, the residual gas in the vacuum duct by using vacuum pressure gauges, etc.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB024

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB026

Frequency and Time Domain Measurement of Coherent Transition Radiation

laser, vacuum, radiation, polarization

143

K. Kan, M. Gohdo, T. Kondoh, I. Nozawa, J. Yang, Y. Yoshida
ISIR, Osaka, Japan

Ultrashort electron beams are essential for light sources and time-resolved measurements. Electron beams can emit terahertz (THz) pulses using coherent transition radiation (CTR). Michelson interferometer is one of can-didates for analyzing the pulse width of an electron beam based on frequency-domain analysis. Recently, electron beam measurement using a photoconductive antenna (PCA) based on time-domain analysis has been investi-gated. In this paper, to improve beam diagnostics of ul-trashort electron beam, investigation of characteristics of a PCA for generation and frequency and time-domain measurement of THz pulses was conducted.
* I. Nozawa et al., Phys. Rev. ST Accel. Beams 17, 072803 (2014).
** K. Kan et al., Appl. Phys. Lett. 102, 221118 (2013).

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB026

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB027

Beam Parameter Measurement After Relocation of S-Band Linear Accelerator

linac, gun, simulation, laser

146

I. Nozawa, M. Gohdo, K. Kan, T. Kondoh, J. Yang, Y. Yoshida
ISIR, Osaka, Japan

Ultrashort electron bunches have been applied in many scientific fields including accelerator physics and radiation chemistry. Pulse radiolysis is application in radiation chemistry, which is a pump-probe measurement using an electron bunch and a laser pulse. Our laboratory aims to generate the electron bunches with durations of less-than femtoseconds using an S-band linear accelerator (linac) at Osaka University in order to improve the time resolution of the pulse radiolysis system. Recently, the linac system was relocated for expanding application using ultrashort electron bunches. The parameters of generated electron bunches including the bunch lengths will be reported.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB027

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB029

Development Status of Linear Focal Cherenkov Ring Camera

vacuum, laser, photon, experiment

152

K. Nanbu, T. Abe, H. Hama, F. Hinode, S. Kashiwagi, T. Muto, I. Nagasawa, H. Saito, K. Takahashi, C. Tokoku
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

Linear focal Cherenkov ring camera (LFC-Camera) has been developed for single shot measurement of longitudinal phase space distribution of quasi-relativistic electron beam, where the electron's velocity still depends on its energy. The LFC-camera employs velocity dependence of opening angle of Cherenkov light produced by electron beam to observe its energy (momentum) distribution. Since the Cherenkov light contains the time information if the radiator medium is thin enough, we can get the longitudinal phase space distribution measuring both time and energy spectra simultaneously using a streak camera. We employ a thin silica aerogel with water-free hydrophobic treatment as Cherenkov radiator. We have evaluated characteristics of the silica aerogel radiator, and demonstration of the LFC-camera at a beam diagnosis section of t-ATCS is being proceeded.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB029

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB030

Development of an EO Sampling Method for THz Pulse Detection

laser, radiation, polarization, experiment

155

T. Toida, M. Washio, R. Yanagisawa
Waseda University, Tokyo, Japan
K. Sakaue
Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan

We have been studying an S-band Cs-Te photo-cathode rf gun at Waseda Univ. The high quality electron beam produced by the rf gun is used to generate a high-power coherent terahertz pulse via Cherenkov radiation. This terahertz pulse can be applied to terahertz imaging and material analysis. As a preliminary step towards material analysis, we conducted experiments on terahertz time domain spectroscopy by EO sampling method to reveal major parameters of the terahertz pulse such as the pulse form and the spectrum. EO sampling method has high frequency response and suitable for high peak power terahertz pulses. In terahertz time domain spectroscopy, the duration of the probe pulse needs to be much faster than that of the terahertz pulse. Therefore, we developed a mode locked Yb-fiber laser based on nonlinear polarization rotation as a reliable and cost-effective ultra-fast probe light source. The laser generates 3.80 ps chirped pulses which are compressed to 213 fs with a grating pair. In this conference, we will report the performance of the Yb-fiber laser and results of EO sampling experiments.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB030

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB033

The Influence of Strip-line BPMs' Measuring Results Made by Edge of the Ultra-relativistic Electron Beam

simulation, wakefield, positron, linac

161

S.Z. Wang, N. Gan, X. Huang
IHEP, Beijing, People's Republic of China

This paper describes the impact on the measuring results of the stripline beam position monitor (BPM) produced by the edge of the ultra-relativistic electron beam when we take the transverse size of the beam into account. Simulations have been made by using the Wakefield Solver of CST Particle Studio. And the result of this influence at different ratio of beam horizontal width σ and the BPM inner diameter a has been obtained. This kind of influence has been observed in the stripline BPMs in the transfer line of Beijing Positron Electron Colliders upgraded version II (BEPCII). The research is useful when we design the inner diameter of the stripline BPMs for ultra-relativistic electron beam, meanwhile it provides reference to distinguish the invalid ones from the measuring results obtained by the stripline BPMs in the ultra-relativistic situation.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB033

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB039

Design of Bunch Length Measurement System at the IRFEL Using a Martin-Puplett Interferometer

radiation, detector, polarization, vacuum

178

T.Y. Zhou, X.Y. Liu, P. Lu, B.G. Sun, L.L. Tang, F.F. Wu, Y.L. Yang, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: Supported by the National Science Foundation of China (11575181, 11175173)
Electron bunch length measurement is of great significance for optimizing IRFEL performance. An optical autocorrelation system using coherent transition radiation (CTR) would be set up to measure the electron bunch length at the IRFEL. CTR can be occurred when short electron bunches traverse a vacuum-metal interface. A Martin-Puplett interferometer allowed measurement of the autocorrelation of the CTR signal. The basic principle and the main components of Martin-Puplett interferometer are elaborated in this paper.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB039

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB041

Modified Trigger Mode of Streak Camera to Measure Bunch Longitudinal Distribution in HLS II

optics, controls, brightness, hardware

184

H. Li, X.Y. Liu, P. Lu, B.G. Sun, L.L. Tang, J.G. Wang, F.F. Wu, Y.L. Yang, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: Supported by the National Science Foundation of China (11575181, 11175173)
In Hefei Light Source, the streak camera was used to measure the bunch length and longitudinal distribution using synchronous light. As the RF frequency of HLS II was 204MHz, the streak camera worked at the frequency of 102MHz (half of 204MHz). Because of the bunch lengthening, the streak camera faced the problem, the streak image on the phosphor screen will overlap when the bunch length was above 200.5ps@5% linear error and 10% overlap. In order to solve this problem, an effective solution was to change the working frequency of the streak camera to 136MHz (two thirds of 204MHz), and then the streak image on the phosphor screen will overlap when the bunch length was above 285.6ps@5% linear error and 10% overlap. So a front-end electronic was needed before the synchronizing signals feed into the streak camera. The front-end electronic was designed to convert the 204MHz synchronizing signal to 136MHz.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB041

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB042

Design and Simulation of Button Beam Position Monitor for IR-FEL*

vacuum, FEL, simulation, electronics

187

X.Y. Liu, P. Lu, B.G. Sun, L.L. Tang, F.F. Wu, Y.L. Yang, T.Y. Zhou, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: * Supported by the National Science Foundation of China (11575181, 11175173)
A new button-type beam position monitor(BPM) was designed for the IR-FEL project. Firstly, the longitudinal size of BPM needs to be short enough to save space because the entire machine of IR-FEL is very compact. And in the matter of installation problem, all four electrodes are deviated 30 degrees from the horizontal axis. Then, according to these two limited conditions and beam parameters, we builded up a simple model and did some simulated calculations to ensure a good performance of position resolution, which should be better than 50μm. The simulations include an estimation of induced signals in both time and frequency domains, horizontal and vertical sensitivities, mapping figures and so on. This button BPM will be manufactured in the near future and then we can do some off-line experiments to test it.
# Corresponding author (email: bgsun@ustc.edu.cn)

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB042

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB046

Design and Calculation Error Analysis of a High Order Mode Cavity Bunch Length Monitor

cavity, positron, simulation, linac

196

J.G. Guo, Q. Luo, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: National Science Foundation of China (11375178) and Fundamental Research Funds for the Central Universities (WK2310000046).
A two-cavity bunch length monitor for linac of positron source is designed. Fifth harmonic cavity resonates at 14.28 GHz (fifth harmonic of the linac fundamental frequency 2.856 GHz) with mode TM020, as this mode could provide larger cavity radius. Each cavity equipped with a filter to suppress unwanted signal. An improved bunch length calculation method was proposed. A simulation was conducted in CST Particle Studio for beam current from 100-300 mA, bunch length from 5-10 ps. Bunch length was calculated and compared by these two methods

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB046

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB048

Bunch Length Measurement at Bunch by Bunch in Harmonics Method at Shanghai SSRF Storage Ring

experiment, injection, storage-ring, synchrotron-radiation

199

L.W. Duan, Y.B. Leng, R.X. Yuan
SINAP, Shanghai, People's Republic of China
N. Zhang
SSRF, Shanghai, People's Republic of China

Harmonics method in frequency domain is an effective and inexpensive bunch length measurement method. With advances in technology, it is possible to do bunch length measurement at bunch by bunch using electronic method. We design and make an electronic system to realize metering at bunch by bunch, and believe it has reasonable bunch length resolution. All selected harmonic signals will be mixed down to 500 MHz and digitized at bunch-by-bunch rate by a multi-channel DBPM processor. The primary beam experiment results will be presented and discussed in this paper.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB048

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB049

Beam Experiment of Low Q CBPM Prototype for SXFEL

cavity, simulation, HOM, FEL

202

J. Chen, L.W. Lai, Y.B. Leng, L.Y. Yu, R.X. Yuan
SINAP, Shanghai, People's Republic of China

To meet the high resolution beam position measurement requirement of micron or sub-micron for shanghai soft X-ray free electron laser (SXFEL) under construction, the cavity beam position monitor (CBPM) operating at C-band and the corresponding electronic has been designed by SINAP. In this paper, the design and optimize of the newly low Q cavity BPM is mentioned, the beam test was conducted on the Shanghai Deep ultraviolet free electron laser (SDUV-FEL) facility. CBPM signal processors including broadband oscilloscope and home-made digital BPM processor have been used to evaluate the system performance as well. The beam experimental result, which matched with MAFIA simulation very well, will be presented and discussed in this paper.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB049

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB051

Cavity BPM Performance Online Evaluation using PCA Method

cavity, experiment, factory, coupling

208

Y.B. Leng, L.W. Lai, L.Y. Yu, R.X. Yuan
SSRF, Shanghai, People's Republic of China
J. Chen, Z.C. Chen
SINAP, Shanghai, People's Republic of China

Funding: NSFS 11575282
This article proposes a new test method to evaluate the performance of cavity beam position monitors using the actual beam as the exciting signal. The new method sepa-rates the signals of different modes and improves the measurement accuracy by eliminating unwanted cou-plings from other sources.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB051

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB054

A High Sensitivity Faraday Cup for Ultrashort Electron Bunches

simulation, gun, laser, experiment

214

S. Setiniyaz, I.H. Baek, B.A. Gudkov, B. Han, K.H. Jang, Y.U. Jeong, H.W. Kim, S.V. Miginsky, J.H. Nam, S. Park, N. Vinokurov
KAERI, Daejon, Republic of Korea
S.V. Miginsky, N. Vinokurov
BINP SB RAS, Novosibirsk, Russia

The UED (Ultrafast Electron Diffraction) beamline of KAERI (Korea Atomic Energy Research Institute) WCI (World Class Institute) Center has been successfully commissioned. A S-band co-axial RF photogun with 1.5 cylindrically symmetric cells was used to remove multiple modes of the electric filed inside the cavity. It is designed to generate sub-picosecond electron bunches with energy up to 3.3~MeV. We have developed a system consists of an in-air Faraday cup (FC) and a preamplifier for charge measurement. Tests performed utilizing 3.3~MeV electrons show the system were able to measure ultrashort bunches with tens of femtosecond pulse duration at 10 fC sensitivity. In this paper, we shall present the design, calibration and test results of this system.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB054

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR001

Micro-mover Development and Test in the PAL-XFEL

solenoid, gun, cavity, controls

229

B.G. Oh, J.H. Han, H. Heo, J.H. Hong, H.-S. Kang, C. Kim, D.E. Kim, K.-H. Park, Y.J. Suh
PAL, Pohang, Kyungbuk, Republic of Korea

Two micro-movers, which are able to control the horizontal, vertical and longitudinal positions as well as the yaw and pitch angles remotely, were developed and installed in the PAL-XFEL linac. The solenoid micro-mover in the gun section allows beam-based alignment of an electron beam to the solenoid field and the gun RF field. The X-band cavity micro-mover minimizes the transverse wake field effect caused by transverse misalignment between the beam and X-band cavity. Two micro-movers has similar specifications and the same mechanism, but the sizes are different from each other. In this paper, we present the design, manufacture and test results of the micro-movers.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR001

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR003

Electron Bunch Length Measurement Using Coherent Radiation Source of fs-THz accelerator at Pohang Accelerator Laboratory

radiation, linac, experiment, target

235

J.H. Ko, I.S. Ko
POSTECH, Pohang, Kyungbuk, Republic of Korea
S.H. Jung, H.-S. Kang, I.S. Ko, J. Park
PAL, Pohang, Kyungbuk, Republic of Korea

A Michelson interferometer was installed at the femtosecond (fs) terahertz (THz) Accelerator of Pohang Accelerator Laboratory(PAL) to measure a subpicosecond order electron bunch length. To measure an ultra-short electron bunch length, we use reconstruction process and fast fourier transform. Currently, we are generating THz radiation with the pulse energy of 7μJ by means of coherent transition radiation (CTR) from a 65-MeV electron beam of the fs-THz accelerator. In this paper, we show the how to make a longitudinal distribution of electron bunch and the radiation intensity difference between CTR and Coherent edge radiation (CER) for nondestructive electron bunch length measurement. And we report the measurement methods to get the fine electron bunch length information.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR003

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR009

Development of Large Aperture Faraday-Cup for LEBT of KHIMA.

ion, proton, ECR, beam-transport

241

J.G. Hwang
KIRAMS/KHIMA, Seoul, Republic of Korea
T.K. Yang
KIRAMS, Seoul, Republic of Korea

Funding: This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIP) (no. NRF-2014M2C3A1029534).
Since an aperture of a low energy beam transport line of the KHIMA is quite large, 100 mm, to minimize an uncontrolled beam loss, large aperture Faraday-cup with the diameter of 100 mm is installed to measure the beam current from the electron cyclotron resonance ion source (ECR-IS) and to identify the ion species using analyzing magnet. The suppression ring is designed to reduce the repelling electrons for an accurate measurement. The Faraday-cup has the cooling channel with the heat capability of 100 W to recover the heat from the ion beam for safety during the operation. In order to reduce the noise propagation from the cooling channel, the cooling channel is insulated with the cup. In this presentation, we show the physical modeling, mechanical aspect for design the large aperture Faraday-cup, and the result of in-beam test with the ECR-IS in KHIMA.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR009

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR013

Development, Calibration and Application of New-generation Dissectors with Picosecond Temporal Resolution

laser, radiation, operation, positron

251

O.I. Meshkov, O. Anchugov, V.L. Dorohov, G.Y. Kurkin, A.V. Petrozhitskii, D.A. Shvedov, E.I. Zinin
BINP SB RAS, Novosibirsk, Russia
P.B. Gornostaev, M.Ya. Schelev, E.V. Shashkov, A. V. Smirnov, A.I. Zarovskii
GPI, Moscow, Russia

Funding: The presented experimental results were implemented due to financial support of the Russian Science Foundation (Projects N 14-29-00295)
A dissector is an electron-optical device designed for measurement of periodic light pulses of subnanosecond and picosecond duration. LI-602 dissector developed at BINP is widely used for routine measurements of a longitudinal profile of electron and positron beams at BINP electron-positron colliders and other similar installations]. This dissector is a part of many optical diagnostic systems and provides temporal resolution of about 20 ps. Recently* a new generation of picosecond dissectors were created on the basis of the PIF-01/S1 picosecond streak-image tube designed and manufactured at the General Physics Institute Photoelectronics Department (Moscow). The device has demonstrated a temporal resolution of 3-4 ps (FWHM). The procedure of temporal resolution calibration and results of application of the new-generation picosecond dissector are given in this work.
*E.I. Zinin, O.I. Meshkov. JINST, 2015 1748-0221 10 P10024 doi:10.1088/1748-0221/10/10/P10024

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR013

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR015

Optical Fibers as a Tool for Gamma Beam Diagnostics at Medical Electron Accelerators

betatron, target, detector, radiation

258

A.I. Novokshonov, V.I. Bespalov, A. Potylitsyn, D.A. Shkitov, S.R. Uglov, A.V. Vukolov
TPU, Tomsk, Russia

Funding: This work was partially supported by the Russian Ministry of Education and Science within the program "Nauka" Grant № 3.709.2014/K.
The existing techniques for gamma beam diagnostics at medical accelerators based on X-ray films have several disadvantages such as insufficient spatial resolution, difficult realization and off-line mode. In the works*,** a feasibility of Cherenkov radiation (CR) in glass fibers for charged particle beam diagnostics was demonstrated. An application of glass fibers scanning for gamma beam diagnostics may have a lot advantages including a possibility of on-line measurements. For this goal we used optical fiber with 0.6 mm diameter and length up to 10 m. An efficiency of CR generation in such fibers and signal attenuation in a long fiber were investigated using the Tomsk microtron electron beam. The shape of gamma beam field produced by the medical SL-75-5MT 6 MeV electron accelerator was measured using the proposed technique. It is shown there it is possible to measure not only gamma beam spatial distribution, but also its angular distribution.
* Wulf, F. and Korfer, M. 2009 Proc. DIPAC2009 411.
** Murokh, A., Agustsson, R., Boucher, S., Frigola, P., Hodgetts, T., Ovodenko, A., Ruelas, M. and Tikhoplav, R. 2012 Proc. IPAC2012 996.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR015

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR017

Design and Simulations of the Cavity BPM Readout Electronics for the ELI-NP Gamma Beam System

cavity, electronics, simulation, linac

264

M. Cargnelutti, B.B. Baricevic
I-Tech, Solkan, Slovenia
A. Mostacci
University of Rome La Sapienza, Rome, Italy
S. Pioli, M. Serio, A. Stella, A. Variola
INFN/LNF, Frascati (Roma), Italy

The Extreme Light Infrastructure - Nuclear Physics (ELI-NP) facility will provide a high intensity laser and a very intense gamma beam which will be used in a broad range of experiments. The gamma beam is obtained through incoherent Compton back-scattering of a laser light off a high brightness electron beam provided by a 700MeV warm LINAC. Electrons are accelerated in trains with up to 32 bunches, each one separated by 16ns. In the laser-electron interaction region, every bunch needs to be monitored with a resolution below 1μm RMS. To achieve this performance, a low-Q cavity beam position monitor will be used in combination with a dedicated data acquisition system able to perform bunch-by-bunch beam position measurements with sub-μm resolution. Using fast A/D converters and specific digital filtering, the readout system proposes an alternative measurement concept. The requirements of the system, its design and the results from the simulations will be presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR017

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR021

Lifetime and Operational Criteria of Proton Beam Instrumentation in the ESS Target Station

proton, radiation, target, monitoring

276

Y. Lee, T.J. Shea, C.A. Thomas
ESS, Lund, Sweden

At the European Spallation Source, a 2 GeV, 5 MW proton beam will be delivered from a superconducting linear accelerator to target at a 4% duty factor, which poses demanding requirements on target station design. To tune the beam delivery system and to protect the target station components, the current density, the halo distribution, and the position of the proton beam shall be measured. To provide this functionality, a suite of beam monitoring devices will be deployed in the target monolith, including a multi-wire grid for the beam profile monitoring, thermo-couple assemblies and secondary emission blades for aperture monitoring, and a beam footprint imaging system consisting of optical components and luminescent coatings. Since these devices are exposed to particles that deposit energy and cause a high rate of radiation damage, it is a significant challenge to ensure full functionality. In this paper, material selection, lifetime estimates and operational criteria for these beam-monitoring devices are presented. A number of particle transport and finite-element simulations are performed for analyses, and an empirical validation plan is presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR023

Surface Characterization and Field Emission Measurements of Copper Samples inside a Scanning Electron Microscope

controls, vacuum, experiment, radio-frequency

283

J. Ögren, V.G. Ziemann
Uppsala University, Uppsala, Sweden
S.H.M. Jafri, K. Leifer
Uppsala University, Department of Engineering Sciences, Uppsala, Sweden

Vacuum breakdown in normal-conducting accelerating structures is a limiting factor for high gradient acceleration. Many aspects of the physics governing the breakdown process and its onset are yet to be fully understood. At Uppsala University we address these questions with an in-situ experimental setup mounted in an environmental scanning electron microscope. It consists of a piezo motor driven tungsten needle and a sample surface mounted on a piezo stage, allowing for nano-meter 3D-position control. One of the piezo motors controls the needle-sample gap while the two other scan across the surface. A DC-voltage up to 1 kV is applied across the gap and field emission currents from a copper surface are measured with an electrometer. Here we present the setup and some initial results.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR023

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR024

A Versatile Beam Loss Monitoring System for CLIC

quadrupole, beam-losses, background, cavity

286

M. Kastriotou, S. Döbert, W. Farabolini, E.B. Holzer, E. Nebot Del Busto, F. Tecker
CERN, Geneva, Switzerland
M. Kastriotou, E. Nebot Del Busto, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
M. Kastriotou, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

The design of a potential CLIC beam loss monitoring (BLM) system presents multiple challenges. To successfully cover the 48 km of beamline, ionisation chambers and optical fibre BLMs are under investigation. The former fulfils all CLIC requirements but would need more than 40000 monitors to protect the whole facility. For the latter, the capability of reconstructing the original loss position with a multi-bunch beam pulse and multiple loss locations still needs to be quantified. Two main sources of background for beam loss measurements are identified for CLIC. The two-beam accelerator scheme introduces so-called crosstalk, i.e. detection of losses originating in one beam line by the monitors protecting the other. Moreover, electrons emitted from the inner surface of RF cavities and boosted by the high RF gradients may produce signals in neighbouring BLMs, limiting their ability to detect real beam losses. This contribution presents the results of dedicated experiments performed in the CLIC Test Facility to quantify the position resolution of optical fibre BLMs in a multi-bunch, multi-loss scenario as well as the sensitivity limitations due to crosstalk and electron field emission.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR024

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR035

Bunch Length Measurements using a Transverse Deflecting Cavity on VELA

gun, cavity, laser, simulation

323

J.W. McKenzie, S.R. Buckley, L.S. Cowie, P. Goudket, M. Jenkins, B.L. Militsyn, A.J. Moss, A.E. Wheelhouse
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
A. Wolski
The University of Liverpool, Liverpool, United Kingdom

The VELA facility at Daresbury Laboratory in the UK includes a 5 MeV/c 2.5 cell S-band photoinjector gun. This gun operates in the "blow-out" regime with a sub-200 fs length drive laser: the resulting bunch length is determined by space-charge effects. We present measurements made with an S-band transverse deflecting cavity to characterise the bunch length as a function of charge, and as a function of the gun operating phase.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR035

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR041

Experimental and Theoretical Studies of the Properties of Coherent Smith-Purcell Radiation

radiation, polarization, background, experiment

344

F. Bakkali Taheri, R. Bartolini, G. Doucas, I.V. Konoplev, A. Reichold
JAI, Oxford, United Kingdom
J. Barros, N. Delerue
LAL, Orsay, France
R. Bartolini
DLS, Oxfordshire, United Kingdom
C.I. Clarke
SLAC, Menlo Park, California, USA

Funding: This work was supported (in parts) by the UK Science and Technology Facilities Council (STFC UK) through grant ST/M003590/1 and The Leverhulme Trust through the International Network Grant IN-2015-012
Previous studies have demonstrated that coherent Smith-Purcell radiation (cSPr) can be used for relativistic electron bunch time profile reconstruction at pico-second and femtosecond scales. The E203 experiments undertaken in May 2015 at FACET (SLAC) were dedicated to the study of some properties of cSPr, namely the azimuthal distribution and the polarization of the radiation. The experimental set up description which allowed such studies will be presented along with the results. To understand the experimental data both semi-analytical and numerical models were studied. The semi-analytical approach was based on the surface-current model, and the 3D particle-in-cell code VSim was used for numerical modeling. The experimental and theoretical studies are compared.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR041

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR045

High Resolution and Dynamic Range Characterisation of Beam Imaging Systems

optics, laser, target, simulation

354

C.P. Welsch, R.B. Fiorito, J. Wolfenden
Cockcroft Institute, Warrington, Cheshire, United Kingdom
M. Bergamaschi, R. Kieffer, T. Lefèvre, S. Mazzoni
CERN, Geneva, Switzerland
R.B. Fiorito, C.P. Welsch, J. Wolfenden
The University of Liverpool, Liverpool, United Kingdom
P. Karataev, K.O. Kruchinin
Royal Holloway, University of London, Surrey, United Kingdom
P. Karataev, K.O. Kruchinin
JAI, Egham, Surrey, United Kingdom

Funding: Work supported by the EU under grant agreement 624890 and the STFC Cockcroft Institute core grant ST/G008248/1.
Any imaging system requires the use of various optical components to transfer the light from the source, e.g. optical radiation generated by a charged particle beam, to the sensor. The impact of the transfer optics on the image resolution is often not well known. To improve this situation, the point spread function (PSF) of the optical system must be measured, preferably, with high dynamic range. For this purpose we have created an intense, small (~ 1 μm) point source using a high quality laser and special focusing optics; and introduced a digital micro-mirror array in the optical system to substantially increase its dynamic range. The PSFs of optical systems that are currently being developed for high resolution, high dynamic range beam imaging using optical transition and diffraction radiation are measured and compared to Zemax simulations. The goal of these studies is to systematically understand and mitigate any ill effects on the PSF due to aberrations, diffraction and misalignment of the components of the imaging system. We present the results of our measurements and simulations.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR045

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR046

Characterizing Supersonic Gas Jet-based Beam Profile Monitors

ion, simulation, vacuum, diagnostics

357

H.D. Zhang, A.S. Alexandrova, A. Jeff, V. Tzoganis, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A.S. Alexandrova, A. Jeff, V. Tzoganis, C.P. Welsch, H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom
A. Jeff
CERN, Geneva, Switzerland

Funding: Work supported by EU under contracts 215080 and 289191, Helmholtz Association (VH-NG-328) and STFC under the Cockcroft Institute core grant ST/G008248/1.
The next generation of high power, high intensity accelerators requires non-invasive diagnostics, particularly beam profile monitors. Residual gas-based diagnostics such as ionization beam profile or beam induced fluorescence monitors have been used to replace commonly used scintillating screens. At the Cockcroft Institute an alternative technique using a supersonic gas jet, shaped into a 45o curtain screen, was developed. It has already demonstrated its superior performance in terms of resolution and signal-to-noise ratio in comparison with residual gas monitors in experimental studies. The performance of this type of monitor depends on the achievable jet homogeneity and quality. Using a movable vacuum gauge as a scanner, the dynamic characteristics of the jet are studied. In this paper we also give an analysis of the resolution for this monitor in detail from the theory and ion drift simulation.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR046

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR052

Single-shot Bunch-by-Bunch Horizontal Beam Size Measurements using a Gated Camera at CesrTA

positron, ion, vacuum, synchrotron-radiation

364

S. Wang
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
R. Holtzapple
CalPoly, San Luis Obispo, California, USA

Funding: Work supported by NSF NSF PHY-1416318, PHYS-1068662, PHYS-1535696
A visible-light beam size monitor has been built and commissioned to measure transverse beam profiles at CESR-TA*. In order to eliminate beam jitter and to study bunch-by-bunch beam dynamics, a fast-gating camera has been utilized to measure single bunch transverse beam profiles. The minimum camera gate width is ~ 3ns which allows us to resolve single bunch beam dynamics along a CesrTA bunch train. Using single bunch interferometry at different bunch currents, we found that the horizontal beam sizes measured by gated camera are consistently less than those measured by a conventional CCD camera, demonstrating the elimination of turn-by-turn beam jitter with single shot capability. By stepping the camera trigger delay, we collected transverse beam profile images from each bunch in a 14ns-spacing 30-bunch train. The horizontal motion of each bunch as well as the horizontal beam size increases dramatically along an electron train but not along positron bunch trains under the same machine condition. The difference in single bunch horizontal dynamics may be a signature for the difference between electron cloud build-up for positron bunch trains versus ions present for electron bunch trains.
* S.T. Wang, D.L. Rubin, J. Conway, M. Palmer, D. Hartill, R. Campbell, R. Holtzapple, NIMA, 703 (2013) 80

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR052

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR054

Double-slit Interferometer Measurements at SPEAR3

synchrotron, synchrotron-radiation, radiation, optics

368

C.L. Li, W.J. Zhang
East China University of Science and Technology, Shanghai, People's Republic of China
M.J. Boland
SLSA, Clayton, Australia
W.J. Corbett, M. Grinberg
SLAC, Menlo Park, California, USA
T.M. Mitsuhashi
KEK, Ibaraki, Japan
Y.H. Xu
DongHua University, Songjiang, People's Republic of China
W.J. Zhang
University of Saskatchewan, Saskatoon, Canada

The resolution of a conventional telescope used to image visible-light synchrotron radiation is often limited by diffraction effects. To improve resolution, the double-slit interferometer method was developed at KEK and has since become popular around the world. Based on the Van Cittert-Zernike theorem relating transverse source profile to transverse spatial coherence, the particle beam size can be inferred by recording fringe contrast as a function of interferometer slit separation. In this paper, we describe the SPEAR3 double-slit interferometer, develop a theoretical framework for the interferometer and provide experimental results. Of note the double-slit system is 'rotated' about the beam axis to map the dependence of photon beam coherence on angle.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR054

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR059

Development of S-band High Power Load

vacuum, klystron, radio-frequency, radiation

383

X.C. Meng, H.B. Chen, C. Cheng, Y.-C. Du, Q. Gao, J. Shi, P. Wang, Z.F. Xiong
TUB, Beijing, People's Republic of China

Several types of S-band high power loads have been designed, manufactured and tested successfully in Tsinghua University. The high power loads, which work at 2856 MHz for 10 MW~100 MW range, are made of all stainless steel. In this paper, we will present the design, fabrication and the high power test results.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR059

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW001

A New Buncher for the ESRF Linac Injector

linac, beam-loading, cavity, gun

389

A.S. Setty, A.S. Chauchat, D. Jousse
Thales Communications & Security (TCS), Gennevilliers Cedex, France
H. Delamare, J. Jacob, B. Ogier, T.P. Perron, E. Rabeuf, C. Richard, V. Serrière, R. Versteegen
ESRF, Grenoble, France

The electron linac was designed to be able to deliver more than 2.5 A in less than 2 ns at 200 MeV within an energy spread of 1% for positrons production at ESRF *. The 200 MeV electron linac was commissioned in 1991. A new gun, a cleaner, a pre-buncher cavity and 4 shielded lenses were tested and installed on the injector in 2008 **. Then, a new Buncher for the ESRF electron linac injector was manufactured and commissioned in 2015. Meanwhile, some new settings were performed to reduce the energy spread for both cases: the long pulse mode and the short pulse mode. The simulations and measurements will be presented.
* D. Tronc et Al. "Electron injector for light source", Proc. EPAC88, Italy, Rome, June 1988.
** T. Perron et Al. "New preinjector for the ESRF booster", Proc. EPAC08, Italy, Genoa, June 2008.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW001

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW003

Thermal Simulation of an Energy Feedback Normal Conducting RF Cavity

cavity, coupling, simulation, operation

396

M. Fakhari, K. Flöttmann, S. Pfeiffer, H. Schlarb
DESY, Hamburg, Germany
J. Roßbach
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
A. Yahaghi
CFEL, Hamburg, Germany

Thermal simulation has been performed for an energy feedback normal conducting RF cavity. The cavity is going to be used as a fast actuator to regulate the arrival time of the electron bunches in fs level in FLASH. By measuring the arrival time jitter of one bunch in a bunch train, the designed cavity apply a correcting accelerating or decelerating voltage to the next bunches. The input power of the cavity is provided by a solid state amplifier and will be coupled to the cavity via a loop on the body. To achieve the fs level precision of the arrival time, the cavity should be able to provide accurate accelerating voltage with a precision of 300 eV. We performed thermal simulation to find out the temperature distribution of the cavity and make sure that heating will not affect its voltage precision. The simulation results show that by using two input loops the coupling constant will vary from 4.11 to 4.13 during the operation of the cavity which effect on the bunchs' arrival time would be less than 0.25 fs. While using just one input loop can lead to an error of about 1 fs.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW003

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW006

The RF System of the ELI-NP Gamma Beam Source

LLRF, linac, klystron, network

407

L. Piersanti, F. Cardelli, L. Palumbo
INFN-Roma1, Rome, Italy
D. Alesini, M. Bellaveglia, R. Boni, A. Gallo, A. Variola
INFN/LNF, Frascati (Roma), Italy
F. Cardelli, L. Palumbo, L. Piersanti
University of Rome La Sapienza, Rome, Italy
G. D'Auria
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

ELI-NP is a linac based gamma-source under construction in Magurele (RO) by the European consortium EuroGammaS led by INFN. Photons with tunable energy (from 0.2 to 19.5 MeV) and with unprecedented intensity and brilliance will be produced by Compton back-scattering between a high quality electron beam (up to 740 MeV), and a 515 nm intense laser pulse. In order to increase the gamma photon flux, the accelerator will operate in multi-bunch at 100 Hz repetition rate, with 32 bunches separated by 16 ns. Three S-band (2856 MHz) RF power plants will feed two room temperature Travelling Wave (TW) structures, a 1.6 cell Standing Wave (SW) S-band gun (which has been manufactured by means of a new technique based on clamped gaskets without brazing) and two SW RF deflectors for longitudinal beam diagnostics. Ten C-band (5712 MHz) RF power plants will feed 12 TW high-order-modes (HOM) damped structures. In this paper, we review the whole ELI-NP RF architecture including the Low Level RF (LLRF) system.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW006

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW010

Property Test of the Q-Factor for High Purity Copper at the Temperature of 20K

cavity, linac, radiation, cryogenics

417

A. Iino
Sokendai, Ibaraki, Japan
K. Endo
TOYAMA Co., Ltd., Zama-shi, Kanagawa, Japan
S. Yamaguchi
KEK, Ibaraki, Japan

A coherent parametric x-ray radiation (PXR) source based on a cryogenic electron linac has been developed by Toyama Co., Ltd, KEK and Nihon University. This accelerator is a C-band normal-conducting compact linac that requires a high Q factor in the accelerating and de-celerating structures. To obtain a high Q factor, the ac-celerating and decelerating structures are operated around 20 K, and are joined by diffusion bonding and are constructed with high-purity 6N8 copper which has very low resistivity in extremely low temperatures. In this study, we report the measurements and calculation of the residual resistance ratio (RRR) for 6N8 copper and oxy-gen-free copper (Class 1) as well as the Q factor for a pillbox cavity made of 6N8 copper and Class 1. The results of a low-power test of this accelerating structure at low temperature are reported. The Q factor for a 6N8 copper pillbox cavity is not much higher than that of a Class 1 pillbox cavity at low temperatures Moreover, the Q factor is saturated when RRR is greater than 500.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW010

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW025

Vacuum RF Breakdown of Accelerating Cavities in Multi-Tesla Magnetic Fields

cavity, vacuum, operation, Windows

444

D.L. Bowring, A. Moretti, M.A. Palmer, D.W. Peterson, A.V. Tollestrup, K. Yonehara
Fermilab, Batavia, Illinois, USA
B.T. Freemire
IIT, Chicago, Illinois, USA
A.V. Kochemirovskiy
University of Chicago, Chicago, Illinois, USA
P.G. Lane, Y. Torun
Illinois Institute of Technology, Chicago, Illinois, USA

Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359.
Ionization cooling of intense muon beams requires the operation of high-gradient, normal-conducting RF structures within multi-Tesla magnetic fields. The application of strong magnetic fields has been shown to lead to an increase in vacuum RF breakdown. This phenomenon imposes operational (i.e. gradient) limitations on cavities in ionization cooling channels, and has a bearing on the design and operation of other RF structures as well, such as photocathodes and klystrons. We present recent results from Fermilab's MuCool Test Area (MTA), in which 201 and 805 MHz cavities were operated at high power both with and without the presence of multi-Tesla magnetic fields. We present an analysis of damage due to breakdown in these cavities, as well as measurements related to dark current and their relation to a conceptual model describing breakdown phenomena.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW025

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW031

Beam Test of a Dielectric Loaded High Pressure RF Cavity for Use in Muon Cooling Channels

cavity, ion, plasma, accelerating-gradient

463

B.T. Freemire
IIT, Chicago, Illinois, USA
D.L. Bowring, A. Moretti, D.W. Peterson, A.V. Tollestrup, K. Yonehara
Fermilab, Batavia, Illinois, USA
A.V. Kochemirovskiy
University of Chicago, Chicago, Illinois, USA
Y. Torun
Illinois Institute of Technology, Chicago, Illlinois, USA

Funding: This work is supported by the Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359.
Bright muon sources require six dimensional cooling to achieve acceptable luminosities. Ionization cooling is the only known method able to do so within the muon lifetime. One proposed cooling channel, the Helical Cooling Channel, utilizes gas filled radio frequency cavities to both mitigate RF breakdown in the presence of strong, external magnetic fields, and provide the cooling medium. Engineering constraints on the diameter of the magnets within which these cavities operate dictate the radius of the cavities be decreased at their nominal operating frequency. To accomplish this, one may load the cavities with a larger dielectric material. A 99.5% alumina ring was inserted in a high pressure RF test cell and subjected to an intense proton beam at the MuCool Test Area at Fermilab. The results of the performance of this dielectric loaded high pressure RF cavity will be presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW031

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW035

Wakefield Excitation in Power Extraction Cavity (PEC) of Co-linear X-band Energy Booster (CXEB) in Time Domain (T3P) with ACE3P

cavity, extraction, booster, simulation

477

T. Sipahi, S. Biedron, S.V. Milton
CSU, Fort Collins, Colorado, USA

In our previous papers we provided the general concept and the design details of our proposed Co-linear X-band Energy Booster (CXEB) as well as more advanced 3D simulations of our system using the frequency domain solvers OMEGA3P and S3P of the ACE3P Suite. Here, using the time domain solver T3P of ACE3P, we provide the single bunch and multiple bunch wakefield excitations resulting from a Gaussian bunch. The related power extraction mechanism for our traveling wave (TW) X-band power extraction cavity (PEC) are also discussed further.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW035

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW036

Frequency Domain Simulations of Co-linear X-band Energy Booster (CXEB) RF Cavity Structures and Passive RF Components with ACE3P

cavity, laser, impedance, extraction

480

T. Sipahi, S. Biedron, S.V. Milton
CSU, Fort Collins, Colorado, USA

Due to their higher intrinsic shunt impedance X-band accelerating structures offer significant gradients with relatively modest input powers, and this can lead to more compact light sources. At the Colorado State University Accelerator Laboratory (CSUAL) [1] we would like to adapt this technology to our 1.3-GHz, L-band accelerator system using a passively driven 11.7 GHz traveling wave X-band configuration that capitalizes on the high shunt impedances achievable in X-band accelerating structures in order to increase our overall beam energy in a manner that does not require investment in an expensive, custom, high-power X-band klystron system. Here we provide the comparisons of the important parameters achieved using SUPERFISH and OMEGA3P for our Co-linear X-band Energy Booster (XCEB) system that will allow us to achieve our goal of reaching the maximum practical net potential across the X-band accelerating structures while driven solely by the beam from the L-band system.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW036

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW037

FEL Simulation Using Distributed Computing

simulation, FEL, GPU, distributed

483

J. Einstein, S. Biedron, H. Freund, S.V. Milton, P.J.M. van der Slot
CSU, Fort Collins, Colorado, USA
G. Bernabeu Altayo
Fermi National Accelerator Laboratory, Batavia, Illinois, USA
S. Biedron
University of Ljubljana, Faculty of Electrical Engineering, Ljubljana, Slovenia
J. Einstein
Fermilab, Batavia, Illinois, USA
P.J.M. van der Slot
Twente University, Laser Physics and Non-Linear Optics Group, Enschede, The Netherlands

While simulation tools are available and have been used regularly for simulating light sources, the increasing availability and lower cost of GPU-based processing opens up new opportunities. This poster highlights a method of how accelerating and parallelizing code processing through the use of COTS software interfaces.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW037

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW038

Measurements of Copper RF Surface Resistance at Cryogenic Temperatures for Applications to X-Band and S-Band Accelerators

cavity, cryogenics, experiment, coupling

487

A.D. Cahill, A. Fukasawa, J.B. Rosenzweig
UCLA, Los Angeles, California, USA
G.B. Bowden, V.A. Dolgashev, M.A. Franzi, S.G. Tantawi, P.B. Welander, C. Yoneda
SLAC, Menlo Park, California, USA
J. Guo
JLab, Newport News, Virginia, USA
Y. Higashi
OIST, Onna-son, Okinawa, Japan

Funding: Funding from DOE SCGSR and DOE/SU Contract DE-AC02-76-SF00515
Recent SLAC experiments with cryogenically cooled X-Band standing wave copper accelerating cavities have shown that these structures can operate with accelerating gradients of ~250 MV/m and low breakdown rates. These results prompted us to perform systematic studies of copper rf properties at cryogenic temperatures and low rf power. We placed copper cavities into a cryostat cooled by a pulse tube cryocooler, so cavities could be cooled to 4K. We used different shapes of cavities for the X-Band and S-Band measurements. Properties of the cavities were measured using a network analyzer. We calculated rf surface resistance from measured Q0 and Q external of the cavity at temperatures from 4 K to room temperature. The results were then compared to the theory proposed by Reuter and Sondheimer. These measurements are a part of studies with the goal of reaching very high operational accelerating gradients in normal conducting rf structures.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW038

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW039

TM01 Mode Launcher for Use in High Brightness Photoguns

quadrupole, gun, impedance, cavity

491

A.D. Cahill
UCLA, Los Angeles, California, USA
M. Dal Forno, V.A. Dolgashev
SLAC, Menlo Park, California, USA

Funding: DOE SCGSR and DOE/SU Contract DE-AC02-76-SF00515
Photo rf guns are a source of electron beams for X-ray FELs such as LCLS and European XFEL. In existing photoguns power is coupled into the cavity by waveguides through the cell walls, like LCLS, or through coaxial coupling, at the European XFEL. We are considering feeding a gun using a circular waveguide with the TM01 mode. To do that we need a mode launcher, a matched device that couples the rectangular TE01 mode waveguide to a TM01 mode in a circular waveguide. Use of the mode launcher reduces complexity of the gun cavity and increases flexibility of positioning the input waveguide relative to the gun body. Mode launchers have been successfully used at SLAC and elsewhere for X-band high gradient tests. Because the existing mode launchers were not built for high brightness guns, they have a significant quadrupole field component. High brightness rf guns have tight requirements on output beam properties, and this quadrupole component adversely affects the beam. We have designed a mode launcher free of this disadvantage. We present design considerations, methodology, and an example S-band mode launcher.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW039

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW040

Electron Beam Excitation of a Surface Wave in mm-Wave Open Accelerating Structures

detector, vacuum, experiment, simulation

494

M. Dal Forno, G.B. Bowden, C.I. Clarke, V.A. Dolgashev, M.J. Hogan, D.J. McCormick, A. Novokhatski, B.D. O'Shea, S.G. Tantawi, S.P. Weathersby
SLAC, Menlo Park, California, USA
B. Spataro
INFN/LNF, Frascati (Roma), Italy

Funding: Work supported by the US DOE under contract DE-AC02-76SF00515.
As part of research on the physics of rf breakdowns we performed experiments with high gradient traveling-wave mm-wave accelerating structures. The accelerating structures are open, composed of two identical halves separated by an adjustable gap. The electromagnetic fields are excited by an ultra-relativistic electron beam. We observed that a confined travelling-wave mode exists in half of the accelerating structure. The experiments were conducted at FACET facility at SLAC National Accelerator Laboratory. Depending on the gap width, the accelerating structure had beam-synchronous frequencies that vary from 90 to 140 GHz. When we opened the gap by more than half wavelength the synchronous wave remains trapped. Its behavior is consistent with the so called "surface wave". We characterized this beam-wave interaction by several methods: measurement of the radiated rf energy with the pyro-detector, measurement of the spectrum with an interferometer, measurement of the beam deflection by using the beam position monitors and profile monitor.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW040

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW041

Measurements of RF Breakdowns in Beam Driven mm-Wave Accelerating Structures

vacuum, experiment, detector, collider

497

M. Dal Forno, G.B. Bowden, C.I. Clarke, V.A. Dolgashev, M.J. Hogan, D.J. McCormick, A. Novokhatski, S.G. Tantawi, S.P. Weathersby
SLAC, Menlo Park, California, USA
B. Spataro
INFN/LNF, Frascati (Roma), Italy

Funding: Work supported by the US DOE under contract DE-AC02-76SF00515
We studied the physics and properties of rf breakdowns in high gradient traveling-wave accelerating structures at 100 GHz. The structures are open, made of two halves with a gap in between. The rf fields were excited in the structure by an ultra-relativistic electron beam generated by the FACET facility at the SLAC National Accelerator Laboratory. We observed rf breakdowns generated in the presence of GV/m scale electric fields. We varied the rf fields excited by the FACET bunch by moving structure relative to the beam and by changing the gap between structure halves. Reliable breakdowns detectors allowed us to measure the rf breakdown rate at these different rf parameters. We measured radiated rf energy with a pyro-detector. When the beam was off-axis, we observed beam deflection in the beam position monitors and on the screen of a magnetic spectrometer. The measurements of the deflection allowed us to verify our calculation of the accelerating gradient.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW041

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW042

Multi-Dimensional RF Sources Design

klystron, cavity, space-charge, gun

501

M. Dal Forno, A. Jensen, R.D. Ruth, S.G. Tantawi
SLAC, Menlo Park, California, USA

Funding: Work supported by the US DOE under contract DE-AC02-76SF00515.
Vacuum electronic devices, such as rf sources for accelerator applications, must provide high rf power with high efficiency. To achieve these requirements, multi-beam klystron and sheet-beam klystron devices have been developed. Multi-beam klystrons, at high frequency employ separate output cavities; hence they have the disadvantage that combining all the rf pulses, generated by all the beams, is challenging. Sheet-beam klystrons have problems with instabilities and with space charge forces that makes the beam not naturally confined. We are proposing an alternative approach that reduces space charge problems, by adopting geometries in which the space charge forces are naturally balanced. An example is when the electron beam is generated by a central source (well) and the electron motion corresponds to the natural expansion of the electron cloud (three-dimensional device). In this paper we will present the design and challenges of a bi-dimensional rf source, a cylindrical klystron, composed by concentric pancake resonant cavities. In this case, space charge forces are naturally balanced in the azimuthal direction.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW042

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMW044

Design of an RF Device to Study the Multipactor Phenomenon

cavity, simulation, multipactoring, experiment

507

D. Amorim
Grenoble-INP Phelma, Grenoble, France
J.-M. De Conto, Y. Gómez Martínez
LPSC, Grenoble Cedex, France

Multipacting is a parasitic electron avalanche process that may occur in RF devices such as cavities or couplers. As it can be detrimental to the operation of these devices, the accelerator group at LPSC is currently designing a coaxial resonant cavity in order to study this phenomenon. In order to determine the measurable parameters on the cavity, calculations were performed and validated with numerical simulations. In a second time multipacting simulations were conducted to determine if the experiment will allow to observe multipacting.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW044

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMY001

Beam Dynamics Analysis for the Ultra-fast Kicker in Circular Cooler Ring of JLEIC

kicker, emittance, cavity, recirculation

510

Y.L. Huang
IMP/CAS, Lanzhou, People's Republic of China
R.A. Rimmer, H. Wang, S. Wang
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
An ultra-fast kicker system consist of four quarter wavelength resonator based deflecting cavities was developed that simultaneously resonates at 10 subharmonic modes of the 476.3MHz bunch repetition frequency, thus every 10th bunch in the bunch train will experience a transverse kick while all the other bunches are undisturbed. This fast kicker is developed for the Energy Recovery Linac (ERL) based electron Circular Cooler Ring (CCR) in the proposed Jefferson Lab Electron Ion Collider (JLEIC, previously MEIC). The electron bunches can be reused 10-30 turns thus the beam current in the ERL can be reduced to 1/10 - 1/30 (150mA - 50mA) of the cooling bunch current (1.5A). In this paper, several methods to synthesis such a kicker waveform will be discussed with the comparison of beam dynamics tracking in Elegant.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY001

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMY003

Transient Beam Loading Effects in RF Systems in JLEIC

cavity, klystron, feedback, controls

518

H. Wang, J. Guo, R.A. Rimmer, S. Wang
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The pulsed electron bunch trains generated from the Continuous Electron Beam Accelerator Facility (CEBAF) linac to inject into the proposed Jefferson Lab Electron Ion Collider (JLEIC) e-ring will produce transient beam loading effects in the Superconducting Radio Frequency (SRF) systems that, if not mitigated, could cause unacceptably large beam energy deviation in the injection capture, exceed the energy acceptance of CEBAF's recirculating arc. In the electron storage ring, the beam abort or ion clearing gaps or uneven bucket filling can cause large beam phase transients in the (S)RF cavity control systems and even beam loss due to Robinson instability. We have first analyzed the beam stability criteria in steady state and estimate the transient effect in Feedforward and Feedback RF controls. Initial analytical models for these effects are shown for the design of the JLEIC e-ring from 3GeV to 12GeV.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY003

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMY009

HOM Consideration of 704 MHz and 2.1 GHz Cavities for LEReC Linac

cavity, HOM, SRF, booster

528

B. P. Xiao, I. Ben-Zvi, M. Blaskiewicz, J.M. Brennan, J.C. Brutus, A.V. Fedotov, H. Hahn, G.T. McIntyre, C. Pai, K.S. Smith, J.E. Tuozzolo, Q. Wu, T. Xin, W. Xu, A. Zaltsman
BNL, Upton, Long Island, New York, USA
S.A. Belomestnykh
Fermilab, Batavia, Illinois, USA
S.A. Belomestnykh, I. Ben-Zvi
Stony Brook University, Stony Brook, USA
V. Veshcherevich
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 and by National Energy Research Scientific Computing Center under contract No. DE-AC02-05CH11231 by US DOE.
To improve RHIC luminosity for heavy ion beam energies below 10 GeV/nucleon, the Low Energy RHIC electron Cooler (LEReC) is currently under development at BNL. The Linac of LEReC is designed to deliver 2 MV to 5 MV electron beam, with rms dp/p less than 5·10^-4. The HOM in this Linac is carefully studied to ensure this specification.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY009

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMY014

Design Study of RF Section and Cavities for Cepc 650 MHz Klystron

klystron, cavity, simulation, bunching

543

O. Xiao
Institute of High Energy Physics (IHEP), People's Republic of China
D.D. Dong, S. Fukuda, Z.J. Lu, G. Pei, S.C. Wang, .. Zaib-un-Nisa, Z.S. Zhou
IHEP, Beijing, People's Republic of China
S. Fukuda
KEK, Ibaraki, Japan

An 800 kW CW klystron operating at 650 MHz is de-veloped for CEPC at Institute of High Energy Physics in China. The conceptual design has been finished and the main parameters are presented in this paper. A 1D large signal disk model code, AJDISK, has been used to design and optimize klystron RF section parameters. In addition, the RF cavities have been designed using SUPERFISH, HFSS and CST.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY014

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMY015

Design Study of Electron Gun for CEPC 650 MHz Klystron

gun, klystron, cathode, simulation

546

.. Zaib-un-Nisa, D.D. Dong, Z.J. Lu, G. Pei, S.C. Wang, O. Xiao, Z.S. Zhou
IHEP, People's Republic of China
S. Fukuda
KEK, Ibaraki, Japan

This paper presents the design and simulation of an electron gun for 800 kW CW klystron of which frequency is 650 MHz for CEPC project. An electron gun with a modulating anode is designed using DGUN software. The uniform beam trajectories, with a beam perveance of 0.64μA/V 3/2 are simulated. We employed a Ba-dispenser cathode of radius 35 mm with Φ10 hole at the center and obtained a current density on cathode less than 0.45 A/cm². The beam trajectories were also simulated over whole tube length with a magnetic field of 207 Gauss. Expecting functions using the modulating anode gun are also described. Proposed beam tester and whole CEPC klystron layout are also shown in this paper.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY015

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMY026

Development of an X-Band Linearizer System for PAL-XFEL

klystron, LLRF, acceleration, wakefield

554

H. Heo, J. Hu, H.-S. Kang, K.H. Kim, S.H. Kim, H.-S. Lee, B.G. Oh, S.S. Park, Y.J. Park, Y.J. Suh
PAL, Pohang, Kyungbuk, Republic of Korea

We developed an X-band RF system for the linear bunch compression in the PAL-XFEL. We installed a SLAC X-band accelerating structure on a precise mover stage and applied RF power by using a SLAC XL-4 11.424 GHz klystron driven by an inverter charging type modulator. We are developing a solid state amplifier controlled by an X-band LLRF system instead of using a TWTA as a driving RF source for the klystron. We present and discuss the recent test results of the system.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY026

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMY033

Effect of Bandwidth of Low Level Radio Frequency System on the Instability of an Electron Beam

feedback, LLRF, cavity, synchrotron

570

Z.K. Liu, L.-H. Chang, M.H. Chang, L.J. Chen, PY. Chen, F.-T. Chung, M.-C. Lin, C.H. Lo, C.L. Tsai, M.H. Tsai, Ch. Wang, M.-S. Yeh, T.-C. Yu
NSRRC, Hsinchu, Taiwan

The analog Low Level Radio Frequency (LLRF) system is used at Taiwan Photon Source (TPS) RF system. It is composed of three feedback loops to control the amplitude and phase of accelerating field and the frequency of RF cavity. Instability of electron beam and accelerating field due to the bandwidth of LLRF system were observed during the TPS commissioning. This effect was studied and the results will be presented in this paper.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY033

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMY034

The Distributed Bunch Amplifier

network, coupling, focusing, distributed

573

M.A. Franzi, A. Jensen, S.G. Tantawi, F. Toufexis, A.R. Vrielink
SLAC, Menlo Park, California, USA

The Distributed Bunch Amplifier (DBA) is a high efficiency RF source that utilizes a phase locked deflecting cavity and output circuit to produce a synchronous beam-wave interaction. The DBA improves on the design of previous embodiments of this technology, such as the Gyrocon*, by implementing a modern decoupled output circuit design and conical PPM beam focusing array in order to scale to higher frequencies and efficiency than previously demonstrated. Presented is a proof-of-concept S-band, 2.856 GHz, device operating with a 60 kV, 8 Amp, electron beam. Each stage of the three-cavity decoupled output circuit is optimized based on complex amplitude and shunt impedance to achieve an electronic efficiency of greater than 90%. Initial numerical analysis of this design indicates that an overall operating efficiency of greater than 70% is feasible. Detailed simulated results of the S-band model and designs to scale this technology to higher power and frequency will be discussed.
* Budker, G. I., et al. "The Gyrocon: An Efficient Relativistic High Power VHF Generator." Part. Accel. 10 (1979): 41-59.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY034

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMY035

Theoretical Analysis and Simulation of a Compact Frequency Multiplier for High Power Millimeter and Terahertz Sources

cavity, cathode, coupling, space-charge

576

A.R. Vrielink, S.G. Tantawi, F. Toufexis
SLAC, Menlo Park, California, USA

As the demands on accelerating gradients and the temporal resolution of beam diagnostics and manipulation schemes grow, millimeter-wave and terahertz (THz) accelerator structures may present a natural solution. The recent advent of a radiofrequency undulator and the development of a 0.45 THz accelerator demonstrate growing interest in this frequency regime; however, growth in this area is limited by the lack of efficient, compact high power sources. We present a novel vacuum electronic device featuring an interaction between a radially bunched electron beam and azimuthally traveling waves. The use of an inward traveling radial sheet beam mitigates space charge effects at the low operating energy of 10-30 keV and allows for a high input beam current of approximately 0.5-10 A. Based on preliminary calculations, these devices could operate from 50 GHz to 250 GHz with tens of kiloWatts of output power, while the expected efficiency would scale from 60% at 80 GHz to 15% at 230 GHz. Here we present the underlying theory, possible structure design, and preliminary results from analytical calculations and simulation.
Tantawi, S. et al. Phys. Rev. Lett. 112, 164802 (April, 2014)
Nanni, E. et al. Nat. Commun. 6, 8486 (October, 2015)

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY035

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMY036

High-harmonic mm-Wave Frequency Multiplication using a Gyrocon-like Device

cavity, coupling, vacuum, plasma

579

F. Toufexis, V.A. Dolgashev, M.V. Fazio, A. Jensen, S.G. Tantawi, A.R. Vrielink
SLAC, Menlo Park, California, USA
P. Borchard
Dymenso LLC, San Francisco, USA

Funding: This project was funded by U.S. Department of Energy under Contract No. DE-AC02-76SF00515, and the National Science Foundation.
Traditional linear interaction RF sources, such as Klystrons and Traveling Wave Tubes, fail to produce significant power levels at millimeter wavelengths. This is because their critical dimensions are small compared to the wavelength, and the output power scales as the square of the wavelength. We present a vacuum tube technology, where the device size is inherently larger than the operating wavelength. We designed a low–voltage mm–wave source, with an output interaction circuit based on a spherical sector cavity. This device was configured as a phased-locked frequency multiplier. We report the design and cold test results of a proof-of-principle fifth harmonic frequency multiplier with an output frequency of 57.12 GHz.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY036

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMY037

GaN Class-F Power Amplifier for Klystron Replacement

klystron, vacuum, operation, controls

583

A.V. Smirnov
RadiaBeam Systems, Santa Monica, California, USA
R.B. Agustsson, S. Boucher, D.I. Gavryushkin, J.J. Hartzell, K.J. Hoyt, A.Y. Murokh, T.J. Villabona
RadiaBeam, Santa Monica, California, USA

Funding: This work was supported by the U.S. Department of Energy (award No. DE-SC0013136)
The vacuum-tube-based RF amplifiers are relatively inefficient and becoming obsolete as the RF world has been progressively converting to solid state technology. Currently, the JLAB upgrade program requires 340 amplifiers capable of 8 kW CW at 1497 MHz while operating at more than 55-60% efficiency to replace their klystrons. Here we explore the possibility of a klystron replacement employing high electron mobility packaged GaN transistors applied in an array of Class-F amplifiers. The inputs and outputs of the many modules needed to make a complete amplifier are connected via precise, in-phase, low-loss, broadband, combiners-dividers. We describe early prototypes of the amplifiers as well as the combiners-dividers and discuss the design features and challenges of such a scheme. This approach can be applied to other national facilities and also for replacement of the klystrons in Middle Energy Electron-Ion Collider which requires about 1.8 MW CW power in total to be produced at 952.6 MHz frequency including 2x12.5 kW power for "crabbing" and 0.53 MW for electron cooling.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY037

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOR005

Longitudinal Wakefields in the Undulator Section of SXFEL User Facility

undulator, FEL, wakefield, vacuum

595

M. Song, H.X. Deng, C. Feng, D. Huang, B. Liu, D. Wang
SINAP, Shanghai, People's Republic of China

Shanghai soft x-ray free electron laser (SXFEL) user facility based on multi-stage seeded-FEL and self-amplified spontaneous emission (SASE) is recently proposed, which is aiming at generating 4-2nm fully-coherent, high-brightness FEL pulse. In this paper, the wakefields arise from the resistive wall and surface roughness in the vacuum chamber is obtained by theoretical models*. And the computations of geometric wakefields are carried out using ABCI**. According to the tracked beam profile, the overall wakefields in the undulator section of SXFEL user facility are presented.
* K. Bane, G. Stupakov, SLAC-PUB-15951, May 2014.
** ABCI website: http://abci.kek.jp/abci.htm

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR005

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOR022

Beam Dynamics Observations of the 2015 High Intensity Scrubbing Runs at the Cern Sps

operation, octupole, injection, emittance

648

H. Bartosik, G. Iadarola, K.S.B. Li, L. Mether, A. Romano, G. Rumolo, M. Schenk
CERN, Geneva, Switzerland

Beam quality degradation caused by e-cloud effects has been identified as one of the main performance limitations for high intensity LHC beams with 25 ns bunch spacing in the SPS. In view of the beam parameters targeted with the LHC injectors upgrade (LIU) project, about two weeks of SPS machine time in 2015 were devoted to dedicated scrubbing runs with high intensity LHC 25 ns and dedicated 'doublet' beams in order to study the achievable reduction of e-cloud effects and quantify the consequent beam performance improvements. This paper describes the main observations concerning the coherent instabilities and beam dynamics limitations encountered as well as a detailed characterisation of the performance reach with the highest beam intensity presently available from the pre-injectors.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR022

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOR026

Measurement of the Energy Distribution Function of Electrons Generated by Radio-frequency Induced Multipacting in a Beam Pipe

multipactoring, gun, radio-frequency, diagnostics

664

M. Van Gompel, F. Caspers, P. Costa Pinto, R. Leber, A. Romano, R. Salemme, M. Taborelli
CERN, Geneva, Switzerland

The development of Electron Multipacting (EM) in high intensity particle accelerators depends, amongst others, on the Secondary Electron Yield (SEY) of surfaces facing the beam. In-situ studies of electron clouds in particle accelerators must cope with operation schedule and other technical constrains. To overcome these difficulties, CERN implemented a Multipactor test bench, where EM is generated by Radio-Frequency (RF), using the beam pipes as a coaxial resonators. This tool was already successfully used to assess the effectiveness of low SEY carbon coatings on dipoles of the SPS at CERN and to study the conditioning dynamics of beam pipes. In this paper we present the development of an in-house built Retarding Field Energy Analyser (RFEA) to measure the Electrons Energy Distribution Function (EEDF) in the Multipactor test bench. The design of the electrodes was based on simulations in order to optimize sensitivity and energy resolution. The setup was tested with an electron gun at different energies before insertion in the Multipactor test bench. The evolution of the EEDF is measured at different RF powers. Feasibility to perform measurements in the machine is discussed.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR026

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOR033

Simulations of Dark Current from the BERLinPro Booster Module

cavity, cathode, booster, simulation

671

M. McAteer, M. Abo-Bakr, B.C. Kuske, A. Neumann
HZB, Berlin, Germany

Funding: Work supported by the German Bundesministerium f\"ur Bildung und Forschung, Land Berlin and grants of Helmholtz Association
Dark current emitted from the surface of high-field RF cavities can contribute to radiation levels and cryo budget and can cause damage to sensitive accelerator components such as the photocathode. The superconducting niobium cavities in the booster module of BERLinPro will have surface fields strong enough to produce significant dark current from field emission, so simulations were made using Astra to track the propagation of emitted electrons from the surfaces of the cavities to examine the effects of dark current in the BERLinPro injector. Results of these simulations, including optimization of the layout to reduce propagation of electrons to the cathode and an estimation of power from dark current deposited throughout the injector, are presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR033

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOR034

Numerical Space-Charge Compensation Studies and Comparison of Different Models

simulation, proton, space-charge, ion

674

D. Noll, M. Droba, O. Meusel, U. Ratzinger, K. Schulte, C. Wiesner
IAP, Frankfurt am Main, Germany

The design of many Low-Energy Beam Transport sections relies on the presence of space-charge compensation by particles of opposing charge. To improve understanding of the processes involved in the built-up and steady-state, simulations using the Particle-in-Cell code bender were made. We will present the influence of various system parameters on the results. Furthermore, the electron velocity distribution was found to be approximately thermal. The spatial distribution can then be found by solving the Poisson-Boltzmann equation. Such a model for the electron distribution was implemented in a 2D PIC code and applied to typical beam transport situations. We will present results in comparison to the 3D simulations.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR034

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOR039

Measurement of Beam Phase at FLASH using HOMs in Accelerating Cavities

HOM, cavity, simulation, coupling

686

L. Shi, R.M. Jones
UMAN, Manchester, United Kingdom
N. Baboi, L. Shi
DESY, Hamburg, Germany
N.Y. Joshi
University of Manchester, Manchester, United Kingdom

The beam phase relative to the accelerating field is of vital importance for the quality of photon beams produced in modern Free Electron Lasers based on superconducting (SC) cavities. Normally, the phase is determined by detecting the transient field induced by the beam. In this way the phase of each cavity is checked and adjusted typically every few months. In this paper, we present another means of beam phase determination, based on higher order modes (HOMs) excited in the 2nd monopole band by the beam inside the SC cavities. A circuit model of this HOM band is also presented. Various effects on the resolution have been studied. Circuit model simulations indicate the resolution is strongly dependent on the signal to noise ratio. Preliminary experimental results, based on a broadband setup, reveal an approximately 0.1o RMS resolution. These are in good agreement with simulation results. The work will pave the way for a dedicated system of beam phase monitoring, which is under development for the European XFEL. This will be the first implementation of a dedicated beam phase monitor, based on beam-excited HOMs in accelerating cavities.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR039

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOR047

Numerical and Experimental Substantiation of the Ion Density Beam Transfer Function Measurements

ion, betatron, space-charge, accumulation

698

D. Sauerland, W. Hillert
ELSA, Bonn, Germany

Funding: Funded by the BMBF, Germany under grant 05K13PDA
In the ELSA stretcher ring electrons are accelerated to a beam energy of 3.2 GeV utilizing a fast energy ramp of 6 GeV/s. Ions being generated by collision with the residual gas molecules accumulate inside the beam potential, causing incoherent tune shifts and coherent beam instabilities. Since the ion induced incoherent tune shift rises linearly with the beam neutralisation, it offers a suitable approach for evaluating the efficiency of several ion clearing measures. It was indirectly measured using a new experimental approach: By measuring the beam transfer function using a broadband transversal kicker, one was able to perceive a shift and broadening of the tune peak. Both effects could be adequately parameterized providing a quantity proportional to the incoherent tune shift and thus the average neutralisation. The impact of incoherent effects to the coherent electron beam response during the measurement has not been subject to intensive theoretical attention yet. This leaves the obtained quantity unscaled. Here new numerical simulations and experimental investigations will be presented in order to further substantiate the results of this new method.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR047

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW003

RF Phase Jitter Consideration in Bunch Compression

klystron, simulation, linac, FEL

704

T.K. Charles, D.M. Paganin
Monash University, Faculty of Science, Clayton, Victoria, Australia
M.J. Boland, R.T. Dowd
SLSA, Clayton, Australia

Error propagation of RF phase jitter is analysed for various linac layout configurations and the sensitivity of the compression ratio due to RF phase jitter is analysed. Multiple sources of jitter have the opportunity to destructively interfere, and (perhaps counter intuitively) found to not add in quadrature. Results are compared to Elegant simulations.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW003

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW004

Electron Trajectory Caustic Formation Resulting in Current Horns present in Bunch Compression

FEL, linac, wakefield, simulation

708

T.K. Charles, D.M. Paganin
Monash University, Faculty of Science, Clayton, Victoria, Australia
M.J. Boland, R.T. Dowd
SLSA, Clayton, Australia

Current horns are ubiquitous in Free Electron Laser (FEL) bunch compression. In this paper, we analyse the formation of these current spikes and identify the cause as caustic formation in the electron trajectories. We also present a possible solution to avoid or mitigate the current horns from developing through using optical linearization.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW004

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW005

First Electron Beam Measurements on COXINEL

laser, undulator, plasma, quadrupole

712

T. André, I.A. Andriyash, C. Basset, C. Benabderrahmane, P. Berteaud, S. Bonnin, F. Bouvet, F. Briquez, L. Cassinari, L. Chapuis, M.-E. Couprie, D. Dennetière, Y. Dietrich, M. Diop, J.P. Duval, M.E. El Ajjouri, T.K. El Ajjouri, P. Gattoni, C. Herbeaux, N. Hubert, M. Khojoyan, M. Labat, N. Leclercq, A. Lestrade, A. Loulergue, O. Marcouillé, F. Marteau, P. Pierrot, F. Polack, F. Ribeiro, J.P. Ricaud, P. Rommeluère, M. Sebdaoui, K.T. Tavakoli, M.-A. Tordeux, M. Valléau, J. Vétéran, D. Zerbib, C. de Olivera
SOLEIL, Gif-sur-Yvette, France
S. Bielawski, C. Evain, C. Szwaj
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
J. Gautier, E. Guillaume, G. Lambert, B. Mahieu, V. Malka, A. Rousse, K. Ta Phuoc, C. Thaury
LOA, Palaiseau, France
E. Roussel
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

The ERC grant COXINEL aims at demonstrating experimentally Free Electron Laser (FEL) amplification with electrons generated by laser plasma acceleration (LPA). Because of the still limited electron beam performance (especially energy spread and divergence) in view of the FEL requirements, the electron beam transfer line has been specifically designed with adequate diagnostics and strong focusing variable strength permanent magnet quadrupoles, an energy de-mixing chicane and second set of quadrupoles for further dedicated focusing in the FEL interaction region, in a U20 in-vacuum undulator, enabling to operate at 200 nm with a 180 MeV electron beam. The first observation and transport of electrons in the COXINEL line is presented here.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW005

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW006

Planning and Controlling of the Cold Accelerator Sections Installation in XFEL

status, laser, free-electron-laser, vacuum

716

M. Bousonville, S. Choroba, F. Eints
DESY, Hamburg, Germany

The installation of the main linear accelerator in the 2 km European XFEL (X-Ray Free-Electron Laser) tunnel is currently under way. The accelerator consists of nine so-called cryo-strings. A typical cryo-string comprises 12 accelerator modules, which will be fed by three RF stations. Furthermore, the installation of electronic racks, cables, power and water supply etc. takes place. To enable a most effective installation of the accelerator components, planning and controlling methods, which had first been developed for the RF system work package, were adapted for the entire main linear accelerator. As a first step, a process plan was developed in cooperation with the work package leaders. On the basis of this plan, the installation process is promoted by several measures: The status of the installation is precisely registered by weekly queries which enable monitoring of the progress and feedback to everyone involved. With this information at hand, the installation process can be controlled and plan deviations can be corrected. Furthermore, the experience gained at one cryo-string is used to optimise the plan for the next cryo-string installation.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW006

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW009

Studies of Harmonic Lasing Self-seeded FEL at FLASH2

undulator, FEL, simulation, radiation

725

E. Schneidmiller, M.V. Yurkov
DESY, Hamburg, Germany

A concept of the Harmonic Lasing Self-Seeded (HLSS) FEL was proposed in*,**. A gap-tunable undulator is divided into two parts such that the first part is tuned to a sub-harmonic of the second part. Harmonic lasing occurs in the exponential gain regime in the first part of the undulator, also the fundamental stays well below saturation. In the second part of the undulator the fundamental mode is resonant to the wavelength, previously amplified as the harmonic. The amplification process proceeds in the fundamental mode up to saturation. In this case the bandwidth is reduced by a significant factor depending on harmonic number but the saturation power is still as high as in the reference case of lasing at the fundamental in the whole undulator, i.e. the spectral brightness increases. Application of the post-saturation tapering would allow to generate higher peak power than in SASE mode due to an improved longitudinal coherence. We present feasibility study of the application of the HLSS FEL scheme at FLASH2 and show that it allows to achieve a higher power and a smaller bandwidth than in a standard SASE regime. First experimental tests are eventually discussed.
* E.A. Schneidmiller and M.V. Yurkov, Phys. Rev. ST-AB 15 (2012) 080702
** E.A. Schneidmiller and M.V. Yurkov, "Harmonic Lasing Self-Seeded FEL", Proc. of FEL2013 Conf., New York, USA

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW009

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW010

The Superconducting Soft X-ray Free-Electron Laser User Facility FLASH

FEL, photon, operation, laser

729

M. Vogt, J. Feldhaus, K. Honkavaara, J. Rönsch-Schulenburg, S. Schreiber, R. Treusch
DESY, Hamburg, Germany

FLASH, the superconducting free-electron laser at DESY delivers up to several thousand photon pulses per second with wavelengths ranging from 52 nm down to as low as 4.2 nm and with pulse energies of up to 500 uJ to photon users at the FLASH1 beamline. In 2014 and 2015 a second beamline, FLASH2, has been commissioned in parallel to user operation at FLASH1. FLASH produces bunch trains of up to 800 bunches in 0.8 ms with a train repetition rate of 10 Hz. Each train can be split in sub-trains for FLASH1 and FLASH2, such that both beamlines receive bursts of bunches with full 10 Hz. Operational highlights are the latest SASE energy record of 600 uJ at 15 nm in FLASH2, and the first simultaneous SASE lasing of three undulator systems: FLASH1 (13.7 nm), sFLASH (38 nm), and FLASH2 (20 nm). sFLASH is the seeding experiment in the FLASH1 beamline. Moreover we will report on recent technical and operational improvements. A major success is the improved reliability and stability of the whole facility with shorter SASE tuning times.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW010

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW011

Operation of Free Electron Laser FLASH Driven by Short Electron Pulses

radiation, undulator, simulation, laser

732

V. Balandin, G. Brenner, C. Gerth, N. Golubeva, U. Mavrič, H. Schlarb, E. Schneidmiller, S. Schreiber, B. Steffen, M. Yan, M.V. Yurkov
DESY, Hamburg, Germany
E. Hass, A. Kuhl, T. Plath, M. Rehders, J. Rönsch-Schulenburg, J. Roßbach
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

The program of low charge mode of operation is under development at free electron laser FLASH aiming in single mode radiation pulses. A short pulse photoinjector laser has been installed at FLASH allowing production of ultrashort electron pluses with moderate compression factor of the beam formation system. Here we present pilot results of free electron laser FLASH operating at the wavelength of 13.1 nm and driven by 70 pC electron bunches. Relevant theoretical analysis has been performed showing good agreement with experimental results.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW011

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW012

Transverse Coherence and Fundamental Limitation on the Pointing Stability of X-ray FELs

FEL, radiation, photon, emittance

735

E. Schneidmiller, M.V. Yurkov
DESY, Hamburg, Germany

The radiation from SASE FEL has always limited value of the degree of transverse coherence*. When transverse size of the electron beam significantly exceeds diffraction limit, the mode competition effect does not provide the selection of the ground mode, and spatial coherence degrades due to contribution of the higher azimuthal modes. An important consequence of this effect are fluctuations of the spot size and pointing stability of the photon beam**. These fluctuations are fundamental and originate from the shot noise in the electron beam. The effect of pointing instability becomes more pronouncing for shorter wavelengths. We analyze in detail the case of optimized SASE FEL* and derive universal dependencies applicable to all operating and planned x-ray FELs. We show that the hard x-ray FELs driven by low energy beams may exhibit poor spatial coherence and bad pointing stability.
* E.L. Saldin, E.A. Schneidmiller and M.V. Yurkov, Opt. Commun. 281(2008)1179.
** E.A. Schneidmiller and M.V. Yurkov, Proc. FEL2015 Conference, Daejeon, Korea, 2015, TUP021.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW012

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW013

Application of Statistical Methods for Measurements of the Coherence Properties of the Radiation from SASE FEL

radiation, FEL, undulator, photon

738

E. Schneidmiller, M.V. Yurkov
DESY, Hamburg, Germany

Radiation of the SASE FEL operating in the linear regime possesses the properties of completely chaotic polarized light which happens due to start up of the amplification properties from the shot noise in the electron beam*. One of the features of this statistical object is that probability distribution of the radiation pulse energy follows gamma distribution. Parameter of this distribution is the number of modes in the radiation pulse which is equal to inverse deviation of the energy fluctuations. Statistical analysis of the radiation energies measured within different spatial apertures allows us to determine the number of longitudinal and transverse modes. In addition, knowledge of the saturation length allows to determine the duration of the lasing part of the electron bunch, photon pulse duration, and coherence time**. Knowledge of the number of transverse modes allows one to determine the degree of transverse coherence. In this report we present theoretical background of the proposed method and experimental results obtained at free electron laser FLASH.
* E.L. Saldin, E.A. Schneidmiller and M.V. Yurkov, Opt. Commun. 148 (1998) 383.
** C. Behrens et al., Phys. Rev. ST Accel. Beams 15 (2012) 030707.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW013

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW014

Measurements of Ultrasmall Charges with MCP Detector in FLASH Accelerator

detector, undulator, photon, laser

741

O.I. Brovko, A.Yu. Grebentsov, A.V. Shabunov, E. Syresin
JINR, Dubna, Moscow Region, Russia
S. Schreiber, M.V. Yurkov
DESY, Hamburg, Germany

Structure of the dark current passed through the undulator is a matter of great concern. Two effects can contribute to the dark current: emission of electrons from "hot" spots in the gun, and generation of "ghost" bunches due to possible leakage of the photoinjector laser. MCP based photon detector has been used for measurements of radiation energy from electron bunch. For small radiation densities the light is detected by direct illumination of the MCP plate, and for large densities a small angle scattering scheme is realized when metallic mesh scatters tiny fraction of light on the MCP plate. In the present experiment we used geometry of direct illumination of MCP plate aiming detection of "ghost" bunches which may generate parasitically from the laser driven electron gun. Reduction of background conditions allowed us to detect light produced by electron bunches with extremely small charges, down to a few femtocoulmb. We measured for the first time structure of the dark current passing through the FLASH undulator. We have also been able to measure a high contrast of radiation produced by the photoinjector laser pulses switched on and off by a 1 MHz repetition rate Pockels cells.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW014

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW015

Fermi Upgrade Plans

FEL, laser, operation, linac

744

A. Fabris, E. Allaria, L. Badano, F. Bencivenga, C. Callegari, F. Capotondi, D. Castronovo, F. Cilento, P. Cinquegrana, M. Coreno, R. Cucini, I. Cudin, G. D'Auria, M.B. Danailov, R. De Monte, G. De Ninno, P. Delgiusto, A.A. Demidovich, S. Di Mitri, B. Diviacco, R. Fabris, W.M. Fawley, M. Ferianis, E. Ferrari, P. Finetti, P. Furlan Radivo, G. Gaio, D. Gauthier, F. Gelmetti, L. Giannessi, F. Iazzourene, M. Kiskinova, S. Krecic, M. Lonza, N. Mahne, M. Malvestuto, C. Masciovecchio, M. Milloch, F. Parmigiani, G. Penco, A. Perucchi, L. Pivetta, O. Plekan, M. Predonzani, E. Principi, L. Raimondi, P. Rebernik Ribič, F. Rossi, E. Roussel, L. Rumiz, C. Scafuri, C. Serpico, P. Sigalotti, M. Svandrlik, C. Svetina, M. Trovò, A. Vascotto, M. Veronese, R. Visintini, D. Zangrando, M. Zangrando
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

FERMI has reached its nominal performance on both FEL lines, FEL-1 (12 eV to 62 eV) and FEL-2 (62 eV to 310 eV). After a brief overview of the activities with users, we will describe plans for LINAC , FEL and beamline upgrades for 2016-2018 and beyond. This includes EEHG schemes for FEL-2.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW015

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW016

Status of Design and Development of Delhi Light Source at IUAC, Delhi

laser, undulator, radiation, gun

748

S. Ghosh, R.K. Bhandari, G.K. Chaudhari, V.J. Joshi, D. Kabiraj, D. Kanjilal, B. Karmakar, J. Karmakar, N. Kumar, P. Patra, B.K. Sahu, A.S. Sharma, A.S. Sthuthikkatt Reghu
IUAC, New Delhi, India
A. Aryshev, M.K. Fukuda, S. Fukuda, N. Terunuma, J. Urakawa, J. Urakawa
KEK, Ibaraki, Japan
A. Deshpande
SAMEER, Mumbai, India
V. Naik, A. Roy
VECC, Kolkata, India
T. Rao
BNL, Upton, Long Island, New York, USA

Funding: The project is supported jointly by Board of Research in Nuclear Sciences (BRNS) and IUAC
The demand for the photon beams for basic research is growing in India. To address the requirements, a project to develop a compact Light Source based on the principle of Free Electron Laser has been initiated at the Inter University Accelerator Centre (IUAC). In the first phase of the project, a normal conducting RF gun will be used to produce electron beam of energy ~ 8 MeV by using copper photocathode and subsequently by Cs2Te photocathode. A high power fiber laser with short pulse length is planned to be used to produce the pre-bunched electron beam by splitting the single laser pulse in to 16 pulses ("comb beam"). The electron beam will be injected in to a compact, variable gap undulator magnet to produce the THz radiation whose frequency can be tuned by varying the undulator field strength and the time separation of the comb beam. In the second and third phases of the project, superconducting RF gun and superconducting accelerating structure will be used to increase the energy of the electron beam up to ~ 40 MeV which will be used to produce IR radiation by using long undulator magnets and to produce X-rays by colliding the electron beam with another high power laser beam.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW016

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW017

Generation of GeV Photons from X-ray Free Electron Laser Oscillators

photon, laser, FEL, scattering

751

R. Hajima
JAEA, Ibaraki-ken, Japan
M. Fujiwara
RCNP, Osaka, Japan

We propose generation of narrow-bandwidth GeV photons, gamma-rays, via Compton scattering of hard X-ray photons in X-ray free-electron laser oscillators. The gamma-rays have a narrow-bandwidth spectrum with a sharp peak, ~0.1% (FWHM), due to the nature of Compton scattering in relativistic regime. Such gamma-rays will be a unique probe for studying hadron physics. We discuss features of the gamma-ray source, flux, spectrum, polarization, tunability and energy resolution.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW017

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW018

Feasibility Study of Photocathode Opearation of Thermionic RF Gun at KU-FEL

FEL, cathode, operation, gun

754

H. Zen, T. Kii, K. Masuda, K. Morita, T. Murata, T. Nogi, H. Ohgaki, S. Suphakul, K. Torgasin
Kyoto University, Kyoto, Japan
R. Kuroda
AIST, Tsukuba, Ibaraki, Japan

Kyoto University Free Electron Laser (KU-FEL) is a mid-infrared FEL driven by a compact linac utilizinig a thermionic RF gun as its electron source*. Recently we succeeded in operating KU-FEL with photocathode operation of the RF gun by using the thermionic cathode (LaB6) as a photocathode. The performance of KU-FEL under the thermionic cathode and photocathode operation will be reported. In addition, some recent application experiment results will also be presented in this presentation.
*H. Zen, et al., Infrared Phys. Techn. 51 (2008) 382.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW018

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW019

Commissioning Status of the Extreme-Ultraviolet FEL Facility at SACLA

FEL, undulator, booster, laser

757

T. Sakurai, T. Asaka, N. Azumi, T. Hara, T. Hasegawa, T. Inagaki, T. Ishikawa, R. Kinjo, C. Kondo, H. Maesaka, T. Ohshima, Y. Otake, H. Tanaka, T. Tanaka, K. Togawa
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
T. Bizen, N. Hosoda, H. Kimura, S. Matsubara, S. Matsui
JASRI/SPring-8, Hyogo, Japan

To equip SACLA with wide ability to provide a laser beams in EUV and soft X-ray regions to experimental users, we have constructed a new free electron laser facility for SACLA beamline-1. Injector components, such as a thermionic electron gun, two buncher cavities, a S-band standing wave accelerator, S-band travelling wave accelerator and their RF sources, were relocated from the SCSS test accelerator, which was a prototype machine of SACLA. At the downstream of a bunch compressor chicane, three C-band 40 MV/m acceleration units were newly installed to effectively boost a beam energy up to 470 MeV. Two in-vacuum undulators were remodeled by changing the period of magnet array from 15 mm to 18 mm to increase SASE intensity by a larger K-value of 2.1. Beam commissioning was started in autumn 2015. So far SASE radiation at a 33 nm wavelength driven by a 470 MeV electron beam was observed. We will install the third undulator in this winter to obtain SASE saturation and additional C-band accelerator units in the next summer to raise the maximum beam energy to 750 MeV. In this presentation, the overview of the facility and the commissioning status will be reported.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW020

Power Improvement of Free-Electron Laser Using Transverse-Gradient Undulator with External Focusing

FEL, focusing, radiation, undulator

760

G. Zhou, Y. Jiao, G. Xu
IHEP, Beijing, People's Republic of China
J. Wu
SLAC, Menlo Park, California, USA
T. Zhang
SINAP, Shanghai, People's Republic of China

Funding: Supported by National Natural Science Foundation of China (11475202, 11405187) and Youth Innovation Promotion Association of Chinese Academy of Sciences (No. 2015009)
Resent study [Z. Huang et al., Phys. Rev. Lett. 10⁹, 204801 (2012)] shows that the transverse-gradient undu-lator (TGU) together with electron beams with constant dispersion can reduce the sensitivity to energy spread for FEL. In this study, we numerically study FEL using TGU with external focusing. In spite of the dispersion varia-tion, through parameter optimization, FEL using TGU with TGU achieves similar radiation to that without ex-ternal focusing. To achieve a high energy exaction effi-ciency, the initial dispersion should be set with a shift from that corresponding to the resonant condition, and a variation of the transverse gradient in different undulator section is preferred. Other approaches, such as tapering and detuning frequency control, are also discussed to further improve the radiation power and are demonstrated with global parametric optimizations base on simulation.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW020

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW022

Model-based Algorithm to Tune the LCLS Optics

quadrupole, optics, controls, undulator

763

Z. Zhang
TUB, Beijing, People's Republic of China
Y. Ding, X. Huang
SLAC, Menlo Park, California, USA

Transverse phase space matching of electron beam to the undulator optics is important for achieving good performance in free-electron lasers. Usually there are dedicated matching quadrupoles distributed in the beamline, by measuring the beam phase space the matching quadrupoles are calculated and adjusted to match to the designed Twiss parameters. Further adjustment of the quadrupoles to overcome collective effects or realistic beamline errors is typically required for performance improvement. In this paper, we studied a method to decompose the Twiss parameters for an independent control of the phase space. Mathematical analysis and numerical simulations are both presented to show that through combining the quadrupoles into some multi-knobs, we can control the Twiss parameters independently. We also show some experimental results at the LCLS.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW022

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW023

Proposal of an X-band Linearizer for Dalian Coherent Light Source

FEL, laser, radiation, undulator

766

G.L. Wang, X.M. Yang, W.Q. Zhang
DICP, Dalian, People's Republic of China
H.X. Deng, C. Feng
SINAP, Shanghai, People's Republic of China

Dalian coherent Light Source (DCLS) is a FEL user facility working at 50-150 nm, now under commissioning in Dalian, China. The facility based on HGHG mode, requires high brightness electron beam with small energy spread and low emittance. To linearise the longitudinal phase space before the bunch compression, an X-band linearizer is considered before the bunch compressor. In this paper, we study the performance improvement of DCLS FEL radiation by using such a harmonic cavity, including the jitter of central wavelength induced by arriving time and a larger bunch compression ratio for femtosecond FEL application.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW023

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW024

Harmonic Lasing Options for Dalian Coherent Light Source

FEL, radiation, laser, undulator

770

G.L. Wang, X.M. Yang, W.Q. Zhang
DICP, Dalian, People's Republic of China
H.X. Deng, C. Feng
SINAP, Shanghai, People's Republic of China

Harmonic lasing of the Free Electron Laser can be achieved by disrupting the electron interaction with the usually dominant fundamental while allowing the increasing of a harmonic interaction. It's a cheap and relatively efficient way to extend the photon energy range of a particular FEL. In this paper, we discussed the possibility of harmonic lasing concept at Dalian Coherent Light Source by using the combination of tapered undulators and phase shifters. Our calculation shows that it's feasible with the present layout to provide intense, stable, and narrow-band harmonic radiation, the FEL wavelength could be down to 20 nm and the corresponding pulse energy is about 10 μJ.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW024

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW026

Status of FELiCHEM, a New IR-FEL in China

FEL, undulator, radiation, cavity

774

H.T. Li, Z.G. He, Q.K. Jia, Q. Luo, L. Wang, S.C. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

FELiChEM is a new experimental facility under construction at University of Science and Technology of China (USTC), whose core device is a FEL oscillator generating middle-infrared and far-infrared laser and covering the spectral range of 2.5-200 μm. It will be a dedicated light source aiming at energy chemistry research, with the photo excitation, photo dissociation and photo detection experimental stations. We present the brief physical and technical design that delivers the required performance for this device and summarize the status of fabrication. Final assembly is scheduled for early in the next year with first light targeted for July 2017.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW026

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW027

Generation of Coherent Mode-locked Radiation in a Seeded Free Electron Laser

radiation, FEL, laser, simulation

777

Z. Wang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China
D. Xiang
Shanghai Jiao Tong University, Shanghai, People's Republic of China

We present the promise of generating mode-locked multichromatic radiations in a seeded free electron laser based on high gain harmonic generation (HGHG). 3D start-to-end simulations have been carried out and analysis & comparisons have been made to have a research on the properties of each system. In these schemes, either the electron beam density or the seed laser intensity is modulated to produce a coherent radiation pulse train that yields multiple spectral lines in FEL output. Stable peak power at gigawatt level can be generated in the undulator finally.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW027

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW028

Research on Pulse Energy Fluctuation of a Cascaded High Gain Harmonic Generation Free Electron Laser

FEL, laser, timing, linac

781

Z. Wang, C. Feng, Q. Gu, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

Shot to shot pulse energy fluctuation is one of the most critical issues for two-stage cascaded high gain harmonic generation (HGHG) free electron lasers (FELs). In this paper, we study the effects of various electron parameters jitters on the output pulse energy fluctuations based on Shanghai Soft X-ray free electron laser facility (SXFEL). The results show that the relative timing jitter between the electron beam and the seed laser is proved to be the most sensitive factor. The energy jitter and charge jitter make some contributions and are non-ignorable as well. Some comparisons between our facility and FERMI have been made and we hope the conclusions draw from this study would be a reference for the optimization of future seeded FEL facilities based on cascading stages of HGHG.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW028

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW029

The Soft X-ray Self-seeding System Design for SXFEL User Facility

undulator, FEL, simulation, photon

785

K.Q. Zhang, T. Liu, D. Wang
SINAP, Shanghai, People's Republic of China
Y. Feng
SLAC, Menlo Park, California, USA

X-ray free electron laser driven by SASE probes the evolution of the new generation light source in high brightness, transverse coherence. However, since SASE achieves lasing from random shotnoise, Poor longitudinal coherence and relative wide bandwidth of SASE FEL limit the operation of many type experiments. Self-seeding as a promising scheme produces longitudinal coherence and even narrower bandwidth radiation by a monochromatic seeding instead of external seeding. The self-seeding system design based on the grating monochromator is carried out for SXFEL user facility across the photon energy from 800-1200 eV. The grating monochromator with a resolution power of 〖10〗^-4 can provide a monochromatic seeding pulse to the seeding undulator. The layout design and simulations of the scheme are presented. It is showing that the self-seeding system for SXFEL user facility is able to improve SASE FEL longitudinal coherence significantly.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW029

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW035

A Compact, Wavelength Tunable MW-THz FEL Amplifier

undulator, FEL, laser, radiation

789

C.H. Chen, A.P. Lee
NSRRC, Hsinchu, Taiwan
F.H. Chao, Y.C. Chiu, Y.-C. Huang, M.H. Wu
NTHU, Hsinchu, Taiwan
G. Zhao
PKU, Beijing, People's Republic of China

We propose a compact scheme of THz free electron laser (FEL) amplifier within a 3.5 m long beam line. The amplification of a tunable THz seed laser in an FEL amplifier is driven by an rf photoinjector*. The THz seed laser is an optical parametric amplifier** pumped by a 1064-nm microchip laser and an external-cavity tunable diode laser. By varying the beam energy and undulator parameter, the radiation frequency of the THz FEL amplifier can be tunable in a broad spectral range between 1.5 and 3.0 THz. Moreover, to extract more radiation power from the electron beam within a short undulator, we employ a linearly tapered undulator in our design. The influence of the seed power on the electron-laser interaction in the undulator is studied in some detail for the FEL amplification. Our simulation results show that the radiation power of the THz FEL amplifier can achieve few MW with a 10-W seed power.
* D.T. Palmer et al., in Proceedings of Particle Acceleration Conference, Vancouver, 1997, p. 2687, (1997).
** S. Hayashi et al., SCIENTIFIC REPORTS, 4, 5045-1-6, (2014).

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW035

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW039

An Oscillator Configuration for Full Realization of Hard X-ray Free Electron Laser

laser, photon, optics, free-electron-laser

801

K.-J. Kim, T. Kolodziej, R.R. Lindberg, D. Shu, Yu. Shvyd'ko, S. Stoupin
ANL, Argonne, Ilinois, USA
V.D. Blank, S. Terentiev
TISNCM, Troitsk, Russia
Y. Ding, W.M. Fawley, J.B. Hastings, Z. Huang, J. Krzywinski, G. Marcus, T.J. Maxwell
SLAC, Menlo Park, California, USA
N.A. Medvedev
CFEL, Hamburg, Germany
W. Qin
PKU, Beijing, People's Republic of China
J. Zemella
DESY, Hamburg, Germany

Funding: Work at ANL supported under US Department of Energy contract DE-AC02-76SF00515 and at SLAC by the U.S. Department of Energy, Office of Science, under Contract No. DE-ACO2-O6CH11357
An X-ray free electron laser can be built in an oscillator (XFELO) configuration by employing an X-ray cavity with Bragg mirrors such as diamond*. An XFELO at the 5th harmonic frequency may be implemented at the LCLS II using its 4 GeV superconducting linac. The XFELO will provide stable, coherent, high-spectral-purity hard x-rays. In addition, portions of its output may be enhanced by the LCLS amplifier for stable pulses of ultrashort duration determined by the electron bunch length. Much progress has been made recently on the feasibility of an XFELO: Analytical and numerical methods have been developed to compute the performance of a harmonic XFELO. The energy spread requirement over a sufficient length of the bunch can be met by temporal shaping of the photo-cathode drive laser**. Experiments at the APS have shown that Be-compound refractive lenses are suitable for a low-loss focusing and that the synthetic diamond crystals can withstand the intense x-ray exposure, in accord with estimates based on molecular dynamics considerations***. A strain-free mounting of thin diamond crystal (< 100 microns) can be realized by shaping a thick diamond into a blind alley****.
* R. R. Lindberg et al., PRSTAB 1010701 (2011)
** W. Qin et al., this conference
*** N. Medvedev et al., Phys. Rev. B 88, 224304 (2013)
**** S. Terentyev, private communication

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW039

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW040

High Efficiency, High Brightness X-ray Free Electron Lasers via Fresh Bunch Self-Seeding

undulator, simulation, extraction, photon

805

C. Emma, C. Pellegrini
UCLA, Los Angeles, USA
M.W. Guetg, A.A. Lutman, A. Marinelli, C. Pellegrini, J. Wu
SLAC, Menlo Park, California, USA

High efficiency, terawatt peak power X-ray Free Electron Lasers are a promising tool for enabling single molecule imaging and nonlinear science using X-rays. Increasing the efficiency of XFELs while achieving good longitudinal coherence can be achieved via self-seeding and undulator tapering. The efficiency of self-seeded XFELs is limited by two factors: the ratio of seed power to beam energy spread and the ratio of seed power to shot noise power. We present a method to overcome these limitations by producing a strong X-ray seed and amplifying it with a small energy spread beam. This is achieved by selectively suppressing lasing for part of the bunch in the SASE section. In this manner we can saturate with the seeding electrons and amplify the strong seed with 'fresh' electrons downstream of the monochromator. Simulations of this scenario are presented for two systems, an optimal superconducting undulator design and the LCLS. In the case of the LCLS we examine how betatron oscillations leading to selective suppression are induced by using the transverse wakefield of a parallel plate dechirper. We also discuss extending the selective suppression scheme to chirped electron bunches.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW040

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW044

Commissioning of the RadiaBeam / SLAC Dechirper

photon, wakefield, controls, alignment

809

M.W. Guetg, K.L.F. Bane, A. Brachmann, A.S. Fisher, Z. Huang, R.H. Iverson, P. Krejcik, A.A. Lutman, T.J. Maxwell, A. Novokhatski, G. Stupakov, J. Zemella, Z. Zhang
SLAC, Menlo Park, California, USA
M.A. Harrison, M. Ruelas
RadiaBeam Systems, Santa Monica, California, USA
J. Zemella
DESY, Hamburg, Germany
Z. Zhang
TUB, Beijing, People's Republic of China

We present results on the commissioning of the two-module RadiaBeam / SLAC dechirper system at LCLS. This is the first installation and measurement of a corrugated dechirper at high energy (4.4 - 13.3 GeV), short pulses (< 200 fs) and while observing its effect on an operational FEL. Both the transverse and longitudinal wakefields allow more flexible electron beam tailoring. We verify that, for a single module at a given gap, the strength of the longitudinal wake on axis and the dipole near the axis agree well with the theoretical values. Using direct longitudinal phase space mapping and X-ray FEL spectrum measurements we demonstrate the energy chirp control capabilities.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW044

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW045

Measurement of Advanced Dispersion-based Beam-tilt Correction

lattice, FEL, photon, laser

813

M.W. Guetg, F.-J. Decker, Y. Ding, P. Emma, Z. Huang, T.J. Maxwell
SLAC, Menlo Park, California, USA

Funding: DOE contract \#DE-AC02-76SF00515
Free electron lasers in the X-ray regime require a good slice alignment along the electron bunch to achieve their best performance. A transverse beam slice shift reduces this alignment and spoils projected emittance and optics matching. Coherent synchrotron radiation, specifically for over-compression going through full compression, and transverse wakefields are major contributors to this. In the case of the large-bandwidth operation, with a strong energy chirp on the bunch, this misalignments furthermore reduce the spectral bandwidth of the FEL pulse. Well-defined manipulation of dispersion allows to compensate for this slice centroid shifts, therefore enhancing lasing power and in case of the large bandwidth mode, spectral bandwidth. This work shows the first application of this correction on an X-ray FEL resulting in increase in beam-power and bandwidth.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW045

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW046

RadiaBeam/SLAC Dechirper as a Passive Deflector

wakefield, lattice, focusing, diagnostics

817

A. Novokhatski, A. Brachmann, M. Dal Forno, V.A. Dolgashev, A.S. Fisher, M.W. Guetg, Z. Huang, R.H. Iverson, P. Krejcik, A.A. Lutman, T.J. Maxwell
SLAC, Menlo Park, California, USA
J. Zemella
DESY, Hamburg, Germany

Funding: This work was supported by Department of Energy Contract No. DE-AC02-76SF00515.
We discuss the possibility of using the RadiBeam/SLAC dechirper recently installed at LCLS for measuring the bunch length of very short bunches, less than 1 fs perhaps as short as 100 atto second. When a bunch travels close to one of the jaws the particles of the bunch get a transverse kick depends upon the position of a particle in a bunch. The tail particles get more kick. The transverse force also gets a nonlinear dependence on the transverse position. The stretched bunch can be measured at the YAG screen that is 100 m downstream the dechirper. The most important aspect of this measurement is that that no synchronization is needed. The Green's function for the transverse kick was evaluated based on the precise wake field calculations of the dechirper corrugated structure*. Using this function we can restore the longitudinal shape of the bunch. This may also help to see if a bunch has any micro-bunch structure.
* A. Noovokhatski "Wakefield potentials of corrugated structures",Phys. Rev. ST Accel. Beams 18, 104402 (2015)

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW046

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW048

Development of the LCLS-II Optics Design

undulator, linac, optics, kicker

820

Y. Nosochkov, P. Emma, T.O. Raubenheimer, M. Woodley
SLAC, Menlo Park, California, USA

Funding: Work supported by the Department of Energy Contract DE-AC02-76SF00515.
The LCLS-II is a high repetition rate, high average brightness free-electron laser (FEL) under construction at the SLAC National Accelerator Laboratory. The LCLS-II will include new major components: a high repetition-rate injector, a superconducting, CW (continuous wave), 4-GeV linac with a bunch compressor system, a 3-way beam spreader, with independent hard X-ray (HXR) and soft X-ray (SXR) FEL undulators. The design is based on the existing SLAC facilities, including the LCLS linac and beam transport lines. The new SXR line will utilize a variable-gap undulator sharing the same tunnel with the new HXR horizontal-gap vertically polarizing undulator that will replace the existing LCLS undulator. We describe the current state of the electron optics design and the latest developments.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW048

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW049

Implementation of a Corrugated-Plate Dechirping System for GeV Electron Beam at LCLS

FEL, controls, laser, experiment

824

M.A. Harrison, P. Frigola, J.D. McNevin, A.Y. Murokh, M. Ruelas
RadiaBeam Systems, Santa Monica, California, USA
A.M. Babbitt, M. Carrasco, A. Cedillos, R.H. Iverson, P. Krejcik, T.J. Maxwell, '. Oven
SLAC, Menlo Park, California, USA

Funding: This work is supported by US DOE Grant No. DE-SC0009550.
A new corrugated-plate Dechirper was recently installed in the LCLS and underwent commissioning tests to gauge its efficacy in shaping the longitudinal phase space of bunches entering the FEL. Here, we describe in detail the completed four-meter LCLS Dechirper system along with a narrative of its construction. We detail the various challenges and lessons learned in the manufacturing and assembly of this first-of-its-kind device. An outlook on future designs is presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW049

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOW052

Status of the Preparation to the Commissioning of the ThomX Storage Ring

storage-ring, dipole, injection, controls

833

I. Chaikovska, C. Bruni, S. Chancé, A.R. Gamelin, H. Monard
LAL, Orsay, France
A. Loulergue
SOLEIL, Gif-sur-Yvette, France

Funding: Work is supported by the French Agence Nationale de la Recherche as part of the program EQUIPEX under reference ANR-10-EQPX-51, the Ile de France region, CNRS-IN2P3 and Université Paris Sud XI
ThomX is a compact Compton based X-ray source under construction at LAL in Orsay (France). The ThomX facility is composed by a 50-70 MeV linac, a transfer line and a 18 meters long Storage Ring (SR). The Compton scattering between the 50 MeV electron bunch of 1 nC and the 30 mJ laser pulses stacked in the Fabry-Perot cavity results in the production of photons with energies (up to 90 keV) with a maximum flux of 10¹³ photons/s. The ThomX construction will start shortly aiming to be completed in the middle of 2017. The preparation to the SR commissioning as far as a control system and beam physics applications are concerned is progressing gradually in order to prepare and test all the tools well ahead the start of the machine. The SR commissioning will face with many challenges providing the low energy, compactness, the nonlinear beam dynamics, the limited beam storage and need for the precision and stabilization in the Interaction Region. Several techniques used at the Synchrotron Light Sources should be modified/adapted to meet all the specificity of the ThomX. This is a report on preparation of the ThomX SR commissioning, its status, planning, main challenges and expectations.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW052

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOY009

ELENA: Installations and Preparations for Commissioning

antiproton, experiment, emittance, extraction

860

C. Carli, W. Bartmann, P. Belochitskii, H. Breuker, F. Butin, T. Eriksson, R. Ostojić, S. Pasinelli, G. Tranquille
CERN, Geneva, Switzerland
W. Oelert
Johannes Gutenberg University Mainz, Institut für Physik, Mainz, Germany

The Extra Low Energy Antiproton ring (ELENA) is a small 30 m circumference synchroton under construction at CERN to further decelerate antiprotons from the Antiproton Decelerator AD from 5.3 MeV to 100 keV. Controlled deceleration in a synchrotron equipped with an electron cooler to reduce emittances in all three planes will allow the existing AD experiments to increase substantially their antiproton capture efficiencies and render new experiments possible. Installation of the machine and lines needed for the commissioning of the ring are ongoing and commissioning is expected to start around mid-2016. The aim is to complete ELENA ring commissioning in November followed by the installation of new electrostatic transfer lines to existing experiments until autumn 2017. Status of ELENA installations and preparations for commissioning will be reported.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY009

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOY025

Electromagnetic Design of β=0.13, f=325 Mhz Half-Wave Resonator for Future High Power, High Intensity Proton Driver at KEK

cavity, linac, proton, rfq

902

G.-T. Park, E. Kako, Y. Kobayashi, T. Koseki, S. Michizono, F. Naito, H. Nakai, K. Umemori, S. Yamaguchi
KEK, Ibaraki, Japan
T. Maruta
KEK/JAEA, Ibaraki-Ken, Japan

At KEK, a proposal is being prepared for a new linac-based proton driver that can accelerate the proton beam up to 9 GeV with 9 MW beam power and 100 mA peak current. In this report, we present the study on the front end design of the linac, which will accelerate the beam to 1.2 GeV: The baseline layout, the acceleration energy structure, RF characteristics of components, cryomodule configurations, and the detailed design of half-wave resonator 1.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY025

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOY039

Progress on Superconducting Linac for the RAON Heavy Ion Accelerator

cryomodule, linac, cavity, ion

935

H.J. Kim, H.C. Jung, W.K. Kim
IBS, Daejeon, Republic of Korea

The RISP (Rare Isotope Science Project) has been proposed as a multi-purpose accelerator facility for providing beams of exotic rare isotopes of various energies. It can deliver ions from proton to uranium. Proton and uranium ions are accelerated upto 600 MeV and 200 MeV/u respectively. The facility consists of three superconducting linacs of which superconducting cavities are independently phased. Requirement of the linac design is especially high for acceleration of multiple charge beams. In this paper, we present the RISP linac design, the prototyping of superconducting cavity and cryomodule.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY039

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOY048

A Novel Approach in the One-Dimensional Phase Retrieval Problem and its Application to the Time Profile Reconstruction

optics, FEL, laser, operation

955

F. Bakkali Taheri, J. Cowley, G. Doucas, S.M. Hooker, I.V. Konoplev
JAI, Oxford, United Kingdom
R. Bartolini
DLS, Oxfordshire, United Kingdom

Funding: This work was supported (in parts) by the UK Science and Technology Facilities Council (STFC UK) grant ST/M003590/1 and The Leverhulme Trust through International Network Grant IN-2015-012
Accurate knowledge of the longitudinal profile of the bunch is important in the context of linear colliders, wake-field accelerators and for the next generation of light sources. As a result the non-destructive, single-shot evaluation of the profile is one of the challenging problems which can be addressed via spectral analysis of coherent radiation generated by a charged particle bunch. To reconstruct the bunch profile from the spectrum the phase retrieval problem has to be solved. Frequently applied methods, e.g. minimal phase retrieval or other iterative algorithms, are reliable if the Blaschke phase contribution is negligible. This is neither known a priori nor can it be assumed to apply to an arbitrary bunch profile. We present a novel approach which gives reproducible, most-probable and stable reconstructions for bunch profiles that would otherwise remain unresolved by the existing techniques. The algorithm proposed uses the output of Kramers-Kronig minimum phase as both initial and boundary conditions, providing a unique solution. To assure a converging solution, new conditions linked to the independently known experimental data such as beam charge were introduced.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY048

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOBA02

ER@CEBAF - A High Energy, Multi-pass Energy Recovery Experiment at CEBAF

linac, experiment, operation, optics

1022

F. Méot, I. Ben-Zvi, Y. Hao, P. Korysko, C. Liu, M.G. Minty, V. Ptitsyn, G. Robert-Demolaize, T. Roser, P. Thieberger, N. Tsoupas
BNL, Upton, Long Island, New York, USA
M.E. Bevins, S.A. Bogacz, D. Douglas, C.J. Dubbe, T.J. Michalski, F.C. Pilat, Y. Roblin, T. Satogata, M. Spata, C. Tennant, M.G. Tiefenback
JLab, Newport News, Virginia, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
A high-energy, multiple-pass energy recovery (ER) experiment proposal, using CEBAF, is in preparation by a JLab-BNL collaboration. The experiment will be proposed in support of the electron-ion collider project (EIC) R&D going on at BNL. This new experiment extends the 2003, 1-pass, 1 GeV CEBAF-ER demonstration into a range of energy and recirculation passes commensurate with BNL's anticipated linac-ring EIC parameters. The experiment will study ER and recirculating beam dynamics in the presence of synchrotron radiation, provide opportunity to develop and test multiple-beam diagnostic instrumentation, and can also probe BBU limitations. This paper gives an overview of the ER@CEBAF project, its context and preparations.

Slides TUOBA02 [1.936 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOBA02

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUZA01

Soft X-ray Free Electron Laser at SINAP

FEL, undulator, laser, radiation

1028

D. Wang
SINAP, Shanghai, People's Republic of China

Shanghai X-ray FEL (SXFEL) is a test facility at Shanghai Institute of Applied Physics, Chinese Academy of Sciences originally designed for studying XFEL principle and technologies. It is composed of a warm linac to provide up to 840 MeV electron beam, an undulator line with cascaded EEHG-HGHG setup and a short diagnostic beamline. The project started the construction by the end of 2014. Recently a proposal to upgrade it to an user facility at the soft x-ray regime got approved. The talk will give an overview of the test facility construction and upgrade plan.

Slides TUZA01 [9.344 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUZA01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUZA02

Twin-bunch Two-colour FEL at LCLS

laser, free-electron-laser, undulator, photon

1032

A. Marinelli, R.N. Coffee, F.-J. Decker, Y. Ding, R.C. Field, S. Gilevich, Z. Huang, D. Kharakh, H. Loos, A.A. Lutman, T.J. Maxwell, J.L. Turner, S. Vetter
SLAC, Menlo Park, California, USA

Twin electron bunches have been the subject of much investigation at the Linac Coherent Light Source, due to their many applications to X-ray free-electron lasers (X-FEL). Twin bunches are trains of two electron bunches that are accelerated and compressed within the same accelerating RF period. At LCLS, these bunches are used in the downstream FEL undulator to generate two X-ray pulses of different energies for pump/probe applications or de novo phase determination of protein crystals. The spectral and temporal shaping of the two bunches requires exquisite control of the compression system to vary the main parameters of the system in a controlled way (peak current, temporal delay and energy separation). I will discuss recent experimental and theoretical results on this subject. In particular I will focus on the demonstration of mJ-level two-color X-ray pulses using twin bunches, as well as the temporal and spectral control of this new mode of operation. Finally, I will discuss our experience with user experiments as well as our future directions of investigation.

Slides TUZA02 [5.738 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUZA02

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOCA01

LCLS Bunch Compressor Configuration Study for Soft X-ray Operation

bunching, laser, linac, operation

1037

S. Li, Y. Ding, Z. Huang, A. Marinelli, T.J. Maxwell, D.F. Ratner, F. Zhou
SLAC, Menlo Park, California, USA
C. Behrens
DESY, Hamburg, Germany

The microbunching instability (MBI) is a well-known problem for high brightness electron beams and has been observed at accelerator facilities around the world. Free-electron lasers (FELs) are particularly susceptible to MBI, which can distort the longitudinal phase space and increase the beam's slice energy spread (SES). Past studies of MBI at the Linac Coherent Light Source (LCLS) relied on optical transition radiation to infer the existence of microbunching. With the development of the x-band transverse deflecting cavity (XTCAV), we can for the first time directly image the longitudinal phase space at the end of the accelerator and complete a comprehensive study of MBI, revealing both detailed MBI behavior as well as insights into mitigation schemes [1]. The fine time resolution of the XTCAV also provides the first LCLS measurements of the final SES, a critical parameter for many advanced FEL schemes. Detailed MBI and SES measurements can aid in understanding MBI mechanisms, benchmarking simulation codes, and designing future high-brightness accelerators.

Slides TUOCA01 [4.436 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOCA01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOCA02

APEX Phase-II Commissioning Results at the Lawrence Berkeley National Laboratory

gun, cavity, linac, space-charge

1041

F. Sannibale, J.A. Doyle, J. Feng, D. Filippetto, G.L. Harris, M.J. Johnson, T.D. Kramasz, D. Leitner, C.E. Mitchell, J.R. Nasiatka, H.A. Padmore, H.J. Qian, H. Rasool, J.W. Staples, S.P. Virostek, R.P. Wells, M.S. Zolotorev
LBNL, Berkeley, California, USA
S.M. Gierman, R.K. Li, J.F. Schmerge, T. Vecchione, F. Zhou
SLAC, Menlo Park, California, USA
C. Pagani, D. Sertore
INFN/LASA, Segrate (MI), Italy

Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231
Science needs in the last decade have been pushing the accelerator community to the development of high repetition rates (MHz/GHz-class) linac-based schemes capable of generating high brightness electron beams. Examples include X-ray FELs; ERLs for light source, electron cooling and IR to EUV FEL applications; inverse Compton scattering X-ray or gamma sources; and ultrafast electron diffraction and microscopy. The high repetition rate requirement has profound implications on the technology choice for most of the accelerator parts, and in particular for the electron gun. The successful performance of the GHz room-temperature RF photo-injectors running at rates <~ 100 Hz, cannot be scaled up to higher rates because of the excessive heat load that those regimes would impose on the gun cavity. In response to this gun need, we have developed at Berkeley the VHF-Gun, a lower-frequency room-temperature RF photo-gun capable of CW operation and optimized for the performance required by MHz-class X-ray FELs. The Advanced Photo-injector EXperiment (APEX) was funded and built for demonstrating the VHF gun performance, and the results of its last phase of commissioning are presented.

Slides TUOCA02 [12.015 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOCA02

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOAB01

Optimization of the Dechirper for Electron Bunches of Arbitrary Longitudinal Shapes

wakefield, simulation, controls, dipole

1054

J.M. Seok, M. Chung
UNIST, Ulsan, Republic of Korea
J.H. Han, J.H. Hong, H.-S. Kang
PAL, Pohang, Kyungbuk, Republic of Korea

Dechirper is a passive device composed of a vacuum chamber of two corrugated, metallic plates with an adjustable gap. By introducing a small offset in the dechirper with respect to the reference axis, one might generate transverse wakefields and use the dechirper as a deflector. Understanding the interactions between electron beams of various longitudinal shapes with the wakefields generated by the dechirper is important to assess the feasibility of the dechirper for use as a deflector. Recently, using a set of alpha-BBO crystals, shaping of laser pulses and electron bunches on the order of ps is tested at the Injector Test Facility (ITF) of Pohang Accelerator Laboratory (PAL). Furthermore, we have investigated propagation of electron bunches of arbitrary longitudinal shapes through the dechirper. In the numerical simulations, we observed that the arbitrary electron beams were successful deflected except for lethal beam shape problems. Hence, in this work, we study optimization of the dechirper for electron bunches of arbitrary longitudinal shapes, using analytical theory and numerical simulations with the ASTRA and ELEGANT codes.

Slides TUOAB01 [1.631 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOAB01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOBB02

FACET-II Accelerator Research with Beams of Extreme Intensities

positron, linac, plasma, damping

1067

V. Yakimenko, Y. Cai, C.I. Clarke, S.Z. Green, C. Hast, M.J. Hogan, N. Lipkowitz, N. Phinney, G.R. White, G. Yocky
SLAC, Menlo Park, California, USA

In 2016, the second phase of SLAC's x-ray laser, the LCLS-II, will begin to use part of the tunnel occupied by FACET, and the world's only multi-GeV facility for advanced accelerator research will cease operation. FACET-II is a new test facility to provide DOE with the unique capability to develop advanced acceleration and coherent radiation techniques with high-energy electron and positron beams. FACET-II is an opportunity to build on the decades-long experience developed conducting advanced accelerator R&D at the FFTB and FACET and re-deploy HEP infrastructure in continued service of its mission. FACET-II provides a major upgrade over current FACET capabilities and the breadth of the potential research program makes it truly unique. It will synergistically pursue accelerator science that is vital to the future of both advanced acceleration techniques for High Energy Physics, ultra-high brightness beams for Basic Energy Science, and novel radiation sources for a wide variety of applications. The presentation will discuss FACET-II project status and plans for diverse experimental program.

Slides TUOBB02 [17.664 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOBB02

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOBB03

CERN AWAKE Facility Readiness for First Beam

proton, plasma, laser, diagnostics

1071

C. Bracco, M. Bernardini, A.C. Butterworth, H. Damerau, S. Döbert, V. Fedosseev, E. Feldbaumer, E. Gschwendtner, W. Höfle, A. Pardons, E.N. Shaposhnikova, H. Vincke
CERN, Geneva, Switzerland

The AWAKE project at CERN was approved in August 2013 and since then a big effort was made to be able to probe the acceleration of electrons before the "2019-2020 Long Shutdown". The next steps in this challenging schedule will be a dry run of all the beam line systems, at the end of the HW commissioning in June 2016, and the first proton beam sent to the plasma cell one month later. The current status of the project is presented together with an outlook over the foreseen works for operation with electrons in 2018.

Slides TUOBB03 [10.682 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOBB03

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOCB01

First Commissioning of the SuperKEKB Vacuum System

vacuum, photon, status, positron

1086

Y. Suetsugu, H. Hisamatsu, T. Ishibashi, K. Kanazawa, K. Shibata, M. Shirai, S. Terui
KEK, Ibaraki, Japan

The SuperKEKB, an electron-positron collider with asymmetric energies in KEK, has started the first commissioning with beams this year. One of major tasks in the commissioning is the beam scrubbing of new beam pipes in order to increase the beam lifetime and to decrease the background noise of the particle detector in the coming physics run. The temperatures and the vacuum pressures of new vacuum components, such as the bellows chambers, gate valves and the beam collimators, should be checked in this run. The decrease rate in the vacuum pressure are measured to estimate the vacuum scrubbing effect. Reported here will be the results obtained during the first commissioning and the present status of the vacuum system.

Slides TUOCB01 [2.526 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOCB01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOCB02

Low Secondary Electron Yield of Laser Treated Surfaces of Copper, Aluminium and Stainless Steel

laser, cavity, framework, photon

1089

R. Valizadeh, P. Goudket, O.B. Malyshev, B.S. Sian, S. Wang
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
M.D. Cropper, S. Wang
Loughborough University, Loughborough, Leicestershire, United Kingdom
P. Goudket
Cockcroft Institute, Warrington, Cheshire, United Kingdom
B.S. Sian
UMAN, Manchester, United Kingdom
N. Sykes
Micronanics Laser Solution Center, Didcot, United Kingdom

Funding: STFC
Reduction of SEY was achieved by surface engineering through laser ablation with a laser operating at • = 355 nm. It was shown that the SEY can be reduced to near or below 1 on copper, aluminium and 316LN stainless steel. The laser treated surfaces show an increased surface resistance, with a wide variation in resistance found de-pending on the exact treatment details. However, a treated copper surface with similar surface resistance to aluminium was produced.

Slides TUOCB02 [94.339 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOCB02

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMB002

Status of THOMX Storage-ring Magnets

quadrupole, sextupole, storage-ring, dipole

1100

C. Vallerand, C. Bruni, A. Gonnin, R. Marie, H. Monard
LAL, Orsay, France
C. Benabderrahmane, M.-E. Couprie, A. Loulergue, F. Marteau
SOLEIL, Gif-sur-Yvette, France

The THOMX facility is a compact X-Ray source based on the Compton back scattering aiming at a flux of 10¹¹ to 1013 ph/s in the range of energy from 40 to 90 keV. Due to the compactness and the expected stability of this machine, high requirements are set for all magnets in terms of design and manufacturing. First, the design optimization of the magnets is presented, leading to high performance in terms of harmonics. Issues regarding the cross-talk between quadrupole and sextupole fields are then discussed.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB002

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMB005

Design and Fabrication of the Compact-Erl Magnets

simulation, quadrupole, sextupole, linac

1111

A. Ueda, K. Endo, K. Harada, T. Kume, T. Miyajima, S. Nagahashi, N. Nakamura, M. Shimada
KEK, Ibaraki, Japan

The compact Energy Recovery Linac (cERL) was con-structed and operated at KEK. For the cERL we designed and fabricated the eight main bending magnets, fifty seven quadrupole magnets, four sextupole magnets and sixteen small bending magnets [1]. These magnets are used at 3 MeV (for low energy part) and 20 MeV (high energy part) beam energy now, but we designed them to be used maximum 10 MeV and 125 MeV beam energy for future upgrade of the cERL. The magnetic field analysis was done by 2D and 3D simulation code (OPERA) to design magnet shape. The main bending magnets and quadrupole magnets are made of electromagnetic steel sheet and the other magnets are made of electromagnetic soft iron. In this paper, we show the detail of the design-ing and fabricating work of those magnets.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB005

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMB006

The Magnetic Measurement of Conventional Magnets for Free-Electron Laser Project of Chinese Academy of Engineering Physics

dipole, collimation, FEL, laser

1115

Z. Zhang, F.S. Chen, Y.F. Yang
IHEP, Beijing, People's Republic of China

The project of free electron laser is worked together completed by CAEP(Chinese Academy of Engineering Physics）and IHEP(Institute of High Energy Physics, China). Conventional magnet of the project includes a total of three deflecting dipole magnet, an analysis of dipole magnet, and two quadrupole magnets. All of magnets to complete the measurement by IHEP Hall measuring equipment. The measurement trajectory of integral magnetic field for deflection dipole magnet is arc and arc tangent direction, using Labview software written a new measurement procedures, the Hall probe directly read absolute value of the three-axis(X, Y, Z) coordinate point (relative to the Hall probe in terms of absolute zero) measurement functions, Not only achieve the purpose of measuring the trajectory can be freely combined, but also effectively eliminate the accumulated error of Hall mobile devices. All measurement results of conventional magnets have reached the physical design requirements, and each magnet were carried out more than twice the measurement, the reproducibility of the measurement results are better than one-thousandth, fully meet the design claim of CAEP.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB006

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMB011

Calculation and Analysis of the Magnetic Field of a Transverse Gradient Undulator

undulator, simulation, FEL, laser

1130

J. Li, B. Du, Q.K. Jia, H.T. Li
USTC/NSRL, Hefei, Anhui, People's Republic of China

Transverse gradient undulator (TGU) is attracting more and more attentions, especially for the rapid progress of laser plasma accelerator techniques. The transverse gradient of TGU is usually given by an empirical formula simply derived from the empirical formula of a uniform-parameter undulator. In this paper, we numerically investigate the transverse magnetic field of TGUs using the RADIA code. Through many simulations for TGUs with different magnet structures, we have given the dependences of transverse gradient parameter on the cant angle, the undulator period and the average gap. Based on these results, when the cant angle is small and the rate of the gap and period is in the range of 0.4-0.6, the simulation results agree with the empirical formula well. But, with the growing of the cant angle, or with the growing of the deviation of the rate of the gap and period from the range of 0.4-0.6, the difference between the simulation results and the empirical formula becomes larger.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB011

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMB015

Compact Rare-Earth Permanent Magnet Material System for Industrial Electron Accelerators Irradiation Field Formation

quadrupole, radiation, permanent-magnet, simulation

1139

D.S. Yurov, A.N. Ermakov, V.V. Khankin, N.V. Shvedunov, V.I. Shvedunov
M.V. Lomonosov Moscow State University (MSU), Skobeltsyn Institute of Nuclear Physics, Moscow, Russia

A compact system for industrial electron accelerators irradiation field formation is described. This system permits to get uniform distribution of electron beam current along the direction perpendicular to product movement with the width 50 - 100 cm. Its main element is a non-linear quadrupole lens, based on rare-earth permanent magnet material. This system can be used instead of an electromagnet of the conventional beam scanning systems, making much more comfortable conditions for products irradiation. Operation principles, results of calculations and test results of the system for CW 1 MeV and pulse 10 MeV electron linear accelerators are described.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB015

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMB016

Continuous-Wave Electron Linear Accelerators for Industrial Applications

linac, klystron, resonance, accelerating-gradient

1142

D.S. Yurov, A.S. Alimov, B.S. Ishkanov, V.I. Shvedunov
MSU, Moscow, Russia

Based on SINP MSU experience in developing continuous wave (CW) normal conducting (NC) electron linacs, we propose an optimal design for such accelerators with beam energy of up to 10 MeV and average beam power of up to several hundred kW. As an example of such design, we discuss the 1 MeV industrial CW linac with maximum beam power of 25 kW, which was recently commissioned at SINP MSU.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB016

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMB026

Magnet System for a Compact Microtron

microtron, permanent-magnet, vacuum, operation

1164

S.A. Kahn, R.J. Abrams, M.A.C. Cummings, R.P. Johnson, G.M. Kazakevich
Muons, Inc, Illinois, USA

Funding: Funded by DOE SBIR grant DE-SC0013795
A compact microtron can be an effective gamma source that can be transported to locations outside the laboratory. As part of a Phase I project we have studied a portable microtron that can accelerate electrons with energies of 6 MeV and above as a source for gamma and neutron production. The mass of the magnet is a significant contribution to the overall mass of the system. This paper will discuss conceptual designs for both permanent magnet and electromagnet systems. The choice of mictrotron RF frequency range is determined by the application requirements. The RF frequency influences the size of the microtron magnet and consequently its weight. We have looked at how the design would vary with the different frequency configurations.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB026

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMB042

Sweet Spot Designs for Interaction Region Septum Magnets

dipole, hadron, quadrupole, shielding

1196

B. Parker
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
A fundamental consideration in designing a high energy collider Interaction Region with electron beams is to avoid production of excessive experimental detector background due to synchrotron radiation. Circumventing such radiation is especially problematic with colliding beams having quite different magnetic rigidities as occurs in both electron-hadron and asymmetric-momentum electron colliders where one must shield an incoming electron beam from the strong magnetic fields needed to focus the other beam. After reviewing some magnetic configurations used to date, we introduce a new 'sweet spot' coil concept that was invented for the eRHIC project proposed at BNL. Sweet spot coils have conductors arranged so that there is an open, low field strength path through the main high field superconducting coil structure. Sweet spot configurations tend to be more efficient than other active and passive shielding solutions. Dipole and quadrupole sweet spot magnet designs examples are presented in this paper along with ongoing R&D to implement and test these concepts.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB042

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMB048

Compensation of Beam Induced Effects in LHC Cryogenic Systems

cryogenics, controls, injection, simulation

1205

B. Bradu, E. Blanco Viñuela, G. Ferlin, B. Fernández Adiego, G. Iadarola, P. Plutecki, E. Rogez, A. Tovar González
CERN, Geneva, Switzerland

This paper presents the different control strategies deployed in the LHC cryogenic system in order to compensate the beam induced effects in real-time. LHC beam is inducing important heat loads along the 27 km of beam screens due to synchrotron radiations, image current and electron clouds. These dynamic heat loads disturb significantly the cryogenic plants and automatic compensations are mandatory to operate the LHC at full energy. The LHC beam screens must be maintained in an acceptable temperature range around 20 K to ensure a good beam vacuum, especially during beam injections and energy ramping where the dynamic responses of cryogenic systems cannot be managed with conventional feedback control techniques. Consequently, several control strategies such as feed-forward compensation have been developed and deployed successfully on the machine during 2015 where the beam induced heat loads are forecast in real-time to anticipate their future effects on cryogenic systems. All these developments have been first entirely modeled and simulated dynamically to be validated, allowing then a smooth deployment during the LHC operation.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB048

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMR002

Suppression of Concomitant Flow of Charged Particles in the Tandem Accelerator with Vacuum Insulation

ion, vacuum, proton, neutron

1225

S.Yu. Taskaev, D.A. Kasatov, A.N. Makarov, Y.M. Ostreinov, I.M. Shchudlo, I.N. Sorokin
BINP SB RAS, Novosibirsk, Russia

Funding: The study was supported by the Grants from the Russian Science Foundation (Project no. 14-32-00006) and the Budker Institute of Nuclear Physics.
A source of epithermal neutrons based on a tandem accelerator with vacuum insulation for Boron Neutron Capture Therapy of malignant tumors was proposed and constructed. Stationary proton beam with 2 MeV energy, 1.6 mA current, 0.1% energy monochromaticity and 0.5% current stability was obtained*. The flow of charged particles accompanying the accelerated ion beam was detected and measured**. To suppress this concomitant flow cooled diaphragm, cryopump and the electrostatic ring were installed in the input of accelerator. The surface of the vacuum vessel was covered with netting to suppress secondary electron emission. These steps have reduced the flow of charged particles 25 % of the ion beam to 0.5 % and to increase the current proton beam 3 times - up to 4.5 mA. The paper presents the results of research and declares plans to use the accelerator for the BNCT.
* D. Kasatov, et al. JINST 9 (2014) P12016.
** D. Kasatov, et al. Technical Physics Letters 41 (2015) 139-141.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR002

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMR003

Three-fold Increase of the Proton Beam Current in the Vacuum Insulation Tandem Accelerator

ion, vacuum, proton, tandem-accelerator

1228

I.M. Shchudlo, V. Dokutovich, D.A. Kasatov, A.N. Makarov, I.N. Sorokin, S.Yu. Taskaev
BINP SB RAS, Novosibirsk, Russia

Funding: The study was supported by the Grants from the Russian Science Foundation (Project no. 14-32-00006) and the Budker Institute of Nuclear Physics
In BINP neutron source for boron neutron capture therapy of cancer based on the vacuum insulation tandem accelerator and lithium target for neutron generation was constructed. After optimization of the injection of negative hydrogen ions and modernization of the stripping target 1.6 mA 2 MeV proton beam was obtained. Improvements of the accelerator to suppress accompanying electron current were introduced, and after making changes to protection system of high voltage power supply a stable proton beam with a current of 4.5 mA was obtained. Analysis of the experimental results shows that the beam is accelerated without losses. Obtaining of proton beam with the current of more than 3 mA offers the prospects of using of accelerators for BNCT in cancer clinics.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR003

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMR005

First Results of a Turbo Generator Test for Powering the HV-Solenoids at a Relativistic Electron Cooler

solenoid, high-voltage, experiment, power-supply

1233

A. Hofmann, K. Aulenbacher, M.W. Bruker, J. Dietrich, T. Weilbach
HIM, Mainz, Germany
W. Klag
IKP, Mainz, Germany
V.V. Parkhomchuk, V.B. Reva
BINP SB RAS, Novosibirsk, Russia

One of the challenges in a relativistic electron cooler is the generation of high voltage exceeding 2 MV and the powering of HV-solenoids, which need a floating power supply. As replacement of the well established, but limited, methods we propose streaming gas for the power transfer. The conversion of the energy by a turbo generator enables using scalable power supply / HV-generator combinations. BINP SB RAS has proposed two possibilities to build the power supply in a modular way. In the first proposal, two cascade transformers per module should be used; the first one powers 22 small HV-solenoids, the second one generates the voltage. In order to reach the final voltage, the modules are cascaded. The cascade transformers are fed by a turbo generator, which is driven by pressurised gas. The second possibility is to use two big HV-solenoids, which are powered directly by a turbo generator. The voltage could be generated for example with a Cockcroft Walton generator. A potential candidate is the Green Energy Turbine (GET) from the company DEPRAG, Germany. At the Helmholtz-Institut Mainz, two GET were tested. In this report, we present our experience and show first results.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR005

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMR006

The ELENA Electron Cooler

gun, solenoid, vacuum, antiproton

1236

G. Tranquille, J. Cenede, A. Frassier, L.V. Jørgensen, A.J. Kolehmainen, B. Moles, M.A. Timmins
CERN, Geneva, Switzerland

The ELENA (Extra Low ENergy Antiproton) ring will deliver antiprotons at an energy of just 100 keV to experiments aiming to precisely measure the properties of anti-hydrogen atoms. A crucial component of this decelerator ring is the electron cooler which will be used to counter the beam blow-up as the antiproton energy is reduced from 5.3 MeV to 100 keV. The electron cooler will operate at energies below 350 eV in a longitudinal guiding field of 100 G such that the perturbations to the ring can be easily corrected. We will present the design considerations as well as the production status of the cooler.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR006

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMR007

Radiative Recombination Detection to Monitor Electron Cooling Conditions During Low Energy RHIC Operations

ion, quadrupole, detector, closed-orbit

1239

F.S. Carlier, M. Blaskiewicz, K.A. Drees, A.V. Fedotov, W. Fischer, M.G. Minty, C. Montag, G. Robert-Demolaize, P. Thieberger
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Providing Au-Au collisions in the Relativistic Heavy Ion Collider (RHIC) at energies equal or lower than 10 GeV/nucleon is of particular interest to study the location of a critical point in the QCD phase diagram. To mitigate luminosity limitations arising from intra-beam scattering at such low energies, an electron cooling system is being developed. To achieve cooling, the relative velocities of the electrons and protons need to be small with maximized transverse overlap. Recombination rates of ions with electrons in the electron cooler can provide signals that can be used to tune the energies and transverse overlap to the required conditions. In this paper we take a close look at various detection methods for recombination processes that may be used to approach cooling.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR007

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMR008

Simulation of Ion Beam under Coherent Electron Cooling

ion, simulation, kicker, FEL

1243

G. Wang, M. Blaskiewicz, V. Litvinenko
BNL, Upton, Long Island, New York, USA
V. Litvinenko
Stony Brook University, Stony Brook, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The proof of coherent electron cooling (CeC) principle experiment is currently under commissioning and it is essential to have the tools to predict the influences of cooling electrons on a circulating ion bunch. Recently, we have developed a simulation code to track the evolution of an ion bunch under the influences of both CeC and Intra-beam scattering (IBS). In this paper, we will first show the results of benchmarking the code with numerical solutions of Fokker-Planck equation and then present the simulation results for the proof of CeC principle experiment.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR008

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMR009

Analytical Studies of Ion Beam Evolution under Coherent Electron Cooling

ion, synchrotron, simulation, scattering

1247

G. Wang, M. Blaskiewicz, V. Litvinenko
BNL, Upton, Long Island, New York, USA
V. Litvinenko
Stony Brook University, Stony Brook, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In the presence of coherent electron cooling (CeC), the evolution of the longitudinal profile of a circulating ion bunch can be described by the 1-D Fokker-Planck equation. We show that, in the absence of diffusion, the 1-D equation can be solved analytically for certain dependence of cooling force on the synchrotron amplitude. For more general cases, we solved the 1-D Fokker-Planck equation numerically and the numerical solutions have been used to benchmark our simulation code as well as providing fast estimations of the cooling effects.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR009

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMR013

Heat Transfer Study of PIG Ion Source for 10 MeV Cyclotron

ion, cathode, ion-source, cyclotron

1256

F. Zakerhosseini, H. Afarideh, S. Sabounchi
AUT, Tehran, Iran
J.-S. Chai, M. Ghergherehchi
SKKU, Suwon, Republic of Korea

A PIG Ion source provides H-ions for the 10 MeV cyclotron, which is designed and being manufactured by Amirkabir university of technology. Plasma created in the anode contains the desired ions. Discharge for producing plasma consists of the both ion current from plasma towards the cathode and the secondary electron current from the cathode to the plasma. Secondary electron emission is the result of ion collision on the surface of the cathode. Heat generated by these collisions is considerably high, so a cooling system for ion source is crucial. In this paper heat transfer study of the ion source, temperature distribution and deformation of different parts simulated using ANSYS CFX. Also the thermionic emission of the electrons from cathode in the calculated temperatures by ANSYS simulated Using CST STUDIO. Results showed the maximum temperature of the cathodes is 1992 K, which is far away from the cathode melting point. The thermionic current in 1992 K of cathode simulated and the results showed an electron current of 0.00706 A at 500 V which is negligible in comparison to the discharge current of 1 A. Maximum deformation were about 0.2 mm in cathode edges.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR013

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMR029

Advanced EBIS Charge Breeder for Rare Isotope Science Project

ion, gun, solenoid, vacuum

1304

S.A. Kondrashev, J.-W. Kim, Y.H. Park
IBS, Daejeon, Republic of Korea
H.J. Son
Handong Global University, Pohang, Republic of Korea

Rare Isotope Science Project (RISP) is under development in Korea to provide wide variety of intense rare isotope beams for nuclear physics experiments and applied science using both Isotope Separation On-Line (ISOL) and In-Flight Fragmentation (IF) techniques. Electron Beam Ion Source (EBIS) charge breeder is a key element to efficiently accelerate rare isotope ion beams produced by ISOL method. These beams will be charge-bred by an EBIS charge breeder to a charge-to-mass ratio (q/A) ≥ - and accelerated by linac post-accelerator to energies of 18.5 MeV/u. Utilization of 3 A electron beam and 6 T superconducting solenoid with wide (8) warm bore diameter will allow high efficient and fast charge breeding of rare isotope beams with exceptional degree of purity. The main features of RISP EBIS charge breeder design and current status of the project will be presented and discussed.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR029

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMR031

Implementation and Preliminary Test of Electron Beam Ion Sources at KOMAC

ion, dipole, rfq, ion-source

1311

S. Lee, Y.-S. Cho, H.S. Kim, H.-J. Kwon
Korea Atomic Energy Research Institute (KAERI), Gyeongbuk, Republic of Korea

Funding: This work has been supported through KOMAC operation fund of KAERI by Ministry of Science, ICT and Future Planning.
Electron beam ion source (EBIS) has been one of widely used table-top devices for the production of highly charged ions by electron impact ionization. An EBIS employs a magnetically compressed, high energy and density electron beam to sequentially ionize atoms or ions with a low charge state*. At KOMAC, we have a compact room-temperature operated EBIS. It is additionally constructed with a magnetic mass spectrometer and a Faraday Cup to measure charge spectra. Using this measurement setup, preliminary tests are performed to find suitable operational potentials in the EBIS for a stable production of highly charge ions. In future, we aim to build an EBIS based pre-injector with a radio frequency quadrupole. It has advantages of having a simple operation and a large number of ion species**. For this, we intend to improve and modify the current EBIS design to incorporate with existing setups at KOMAC.
* M. A. Levin et al., Phys. Scr. T22, 157-163 (1988)
** J. Alessi et al., EBIS Pre-Injector Project Conceptual Design Report, Brookhaven National Laboratory (2005)

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR031

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMR056

Development and Investigation of Pulsed Pinch Plasmas for the Application as FAIR Plasma Stripper

plasma, ion, heavy-ion, cathode

1387

M. Iberler, T. Ackermann, B. Bohlender, C. Hock, J. Jacoby, D. Mann, A. Puth, J. Wiechula
IAP, Frankfurt am Main, Germany
G. Ge
GSI, Darmstadt, Germany

Funding: This work is supported by BMBF
The planed Facility for Ion Research (FAIR) is a new international accelerator laboratory at the GSI in Darm-stadt, Germany. The main topic at this facility is aimed to heavy ion research. The FAIR project in comparison to the existing facility GSI extends the research area by raising the energy of ion beams. After creation of the ion beam at the ion source the state charge is low. Therefor the demand for acceleration of the beam to the highest possible energy is a highly ionized charge state of the beam. For beam stripping to get higher charge state, the traditional tools are gas stripper and foil stripper [1, 2]. Hence Plasma is suggested to be a stripper medium. In Frankfurt are different kinds of Pinch Plasmas under investigation for Stripper. The constricting effect on the plasma or conductor is produced by the magnetic field pressure resulting from the current or by the Lorentz force produced by the current flowing in its own magnetic field. In addition to separate the high pressure discharge cham-ber of the accelerator a plasma window will be used [3]. This contribution gives an overview of the plasma proper-ties and shows first results of different beam times at the GSI.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR056

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMW011

Current Status of Instability Threshold Measurements in the LHC at 6.5 TeV

octupole, damping, impedance, simulation

1434

L.R. Carver, J. Barranco, N. Biancacci, X. Buffat, W. Höfle, G. Kotzian, T. Lefèvre, T.E. Levens, E. Métral, T. Pieloni, B. Salvant, C. Tambasco
CERN, Geneva, Switzerland
N. Wang
IHEP, Beijing, People's Republic of China
M. Zobov
INFN/LNF, Frascati (Roma), Italy

Throughout 2015, many measurements of the minimum stabilizing octupole current required to prevent coherent transverse instabilities have been performed. These measurements allow the LHC impedance model at flat top to be verified and give good indicators of future performance and limitations. The results are summarized here, and compared to predictions from the simulation code DELPHI.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW011

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMW016

Effect of the LHC Beam Screen Baffle on the Electron Cloud Buildup

simulation, shielding, proton, dipole

1454

A. Romano, G. Iadarola, K.S.B. Li, G. Rumolo
CERN, Geneva, Switzerland

Funding: Research supported by the High Luminosity LHC project
Electron Cloud (EC) has been identified as one of the major intensity-limiting factors in the CERN Large Hadron Collider (LHC). Due to the EC, an additional heat load is deposited on the perforated LHC beam screen, for which only a small cooling capacity is available. In order to preserve the superconducting state of the magnets, pumping slots shields were added on the outer side of the beam screens. In the framework of the design of the beam screens of the new HL-LHC triplets, the impact of these shields on the multipacting process was studied with macroparticle simulations. For this purpose multiple new features had to be introduced in the PyECLOUD code. This contribution will describe the implemented simulation model and summarize the outcome of this study.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW016

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMW017

Electron Cloud Observations during LHC Operation with 25 ns Beams

operation, injection, simulation, cryogenics

1458

K.S.B. Li, H. Bartosik, G. Iadarola, L. Mether, A. Romano, G. Rumolo, M. Schenk
CERN, Geneva, Switzerland

While during the Run 1 (2010-2012) of the Large Hadron Collider (LHC) most of the integrated luminosity was produced with 50 ns bunch spacing, for the Run 2 start-up (2015) it was decided to move to the nominal bunch spacing of 25 ns. As expected, with this beam configuration strong electron cloud effects were observed in the machine, which had to be mitigated with dedicated 'scrubbing' periods at injection energy. This enabled to start the operation with 25 ns beams at 6.5 TeV, but e-cloud effects continued to pose challenges while gradually increasing the number of circulating bunch trains. This contribution will review the encountered limitations and the mitigation measures that where put in place and will discuss possible strategies for further performance gain.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW017

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMW023

Macroparticle-Induced Losses During 6.5 TeV LHC Operation

operation, proton, beam-losses, luminosity

1481

G. Papotti, M. Albert, B. Auchmann, E.B. Holzer, M.K. Kalliokoski, A. Lechner
CERN, Geneva, Switzerland

One of the major performance limitations for operating the LHC at high energy was feared to be the so called UFOs (Unidentified Falling Objects, presumably micrometer sized dust particles which lead to fast beam losses when they interact with the beam). Indeed much higher rates were observed in 2015 compared to Run 1, and about 20 fills were prematurely terminated by too high losses caused by such events. Additionally they triggered a few beam induced quenches at high energy, the first in the history of the LHC. In this paper we review the latest update on the analysis of these events, e.g. the conditioning observed during the year and possible correlations with beam and machine parameters. At the same time we also review the optimization of beam loss monitor thresholds in terms of machine protection and availability.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW023

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMW035

Performance and Operational Aspects of HL-LHC Scenarios

luminosity, optics, simulation, emittance

1516

L.E. Medina Medrano
DCI-UG, León, Mexico
R. Tomás
CERN, Geneva, Switzerland

Funding: Research supported by the High Luminosity LHC project. Work supported by the Beam Project (CONACYT, Mexico).
Several alternatives to the present HL-LHC baseline configuration have been proposed, aiming either to improve the potential performance, reduce its risks, or to provide options for addressing possible limitations or changes in its parameters. In this paper we review and compare the performance of the HL-LHC baseline and the main alternatives with the latest parameters set. The results are obtained using refined simulations of the evolution of the luminosity with β^*-levelling, for which new criteria have been introduced, such as improved calculation of the intrabeam scattering and the addition of penalty steps to take into account the necessary time to move between consecutive optics during the process. The features of the set of optics are discussed for the nominal baseline.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW035

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMW040

Beam-beam Simulation for the 2015 RHIC Proton Run with Electron Lenses

proton, dynamic-aperture, lattice, simulation

1533

Y. Luo, W. Fischer, X. Gu, G. Robert-Demolaize, V. Schoefer
BNL, Upton, Long Island, New York, USA
S.M. White
ESRF, Grenoble, France

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Electron lenses were used for head-on beam-beam compensation for the first time in the 2015 Relativistic Heavy Ion Collider (RHIC) 100~GeV polarized proton run. Lattices with the achromatic telescopic squeeze (ATS) scheme of β^* are adopted to improve the off-momentum dynamic aperture. The phase advances between the electron lenses to one of the two collisional points are set to kπ to minimize the beam-beam resonance driving terms. In this article, we present the results from weak-strong and strong-strong beam-beam simulations with head-on beam-beam compensations for these lattices. Simulations are also carried out aiming to explain the observations from operation.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW040

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMY001

Very Low Emittance Muon Beam using Positron Beam on Target

positron, target, emittance, collider

1536

M. Antonelli, M.E. Biagini, M. Boscolo, A. Variola
INFN/LNF, Frascati (Roma), Italy
E. Bagli
INFN-Ferrara, Ferrara, Italy
G. Cavoto
INFN-Roma, Roma, Italy
P. Raimondi
ESRF, Grenoble, France

Muon beams are customarily obtained via K/π decays produced in proton interaction on target. In this paper we investigate the possibility to produce low emittance muon beams from electron-positron collisions at centre-of-mass energy just above the μ⁺{+}μ⁺{-} production threshold with maximal beam energy asymmetry, corresponding to a positron beam of about 45 GeV interacting on electrons on target. Performances on both amorphous and crystal target are presented, and the general scheme for the muon production will be given. We present the main features of this scheme with a first preliminary evaluation of the performances that could be achieved by a multi-TeV muon collider.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY001

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMY009

MuSim, a Graphical User Interface for Multiple Simulation Programs

simulation, interface, proton, real-time

1559

T.J. Roberts, M.A.C. Cummings, R.P. Johnson
Muons, Inc, Illinois, USA
D.V. Neuffer
Fermilab, Batavia, Illinois, USA

MuSim is a new user-friendly program designed to interface to many different particle simulation codes, regardless of their data formats or geometry descriptions. It presents the user with a compelling graphical user interface that includes a flexible 3-D view of the simulated world plus powerful editing and drag-and-drop capabilities. All aspects of the design can be parametrized so that parameter scans and optimizations are easy. It is simple to create plots and display events in the 3-D viewer (with a slider to vary the transparency of solids), allowing for an effortless comparison of different simulation codes. Simulation codes: G4beamline, MAD-X, and MCNP; more coming. Many accelerator design tools and beam optics codes were written long ago, with primitive user interfaces by today's standards. MuSim is specifically designed to make it easy to interface to such codes, providing a common user experience for all, and permitting the construction and exploration of models with very little overhead. For today's technology-driven students, graphical interfaces meet their expectations far better than text-based tools, and education in accelerator physics is one of our primary goals.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY009

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMY011

Simulated Measurements of Cooling in Muon Ionization Cooling Experiment

lattice, emittance, solenoid, detector

1565

T.A. Mohayai
IIT, Chicago, Illinois, USA
C.T. Rogers
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
P. Snopok
Fermilab, Batavia, Illinois, USA
P. Snopok
Illinois Institute of Technology, Chicago, Illlinois, USA

Cooled muon beams set the basis for the exploration of physics of flavour at a Neutrino Factory and for multi-TeV collisions at a Muon Collider. The international Muon Ionization Cooling Experiment (MICE) measures beam emittance before and after an ionization cooling cell and aims to demonstrate emittance reduction in muon beams. In the current MICE Step IV configuration, the MICE muon beam passes through low-Z absorber material for reducing its transverse emittance through ionization energy loss. Two scintillating fiber tracking detectors, housed in spectrometer solenoid modules upstream and downstream of the absorber are used for reconstructing position and momentum of individual muons for calculating transverse emittance reduction. However, due to existence of non-linear effects in beam optics, transverse emittance growth can be observed. Therefore, it is crucial to develop algorithms that are insensitive to this apparent emittance growth. We describe a different figure of merit for measuring muon cooling which is the direct measurement of the phase space density.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY011

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMY015

Ultrafast Electron Guns for the Efficient Acceleration using Single-Cycle THz Pulses

gun, acceleration, laser, injection

1578

A. Fallahi, F.X. Kärtner, A. Yahaghi
CFEL, Hamburg, Germany
M. Fakhari
DESY, Hamburg, Germany

Funding: European Research Council (ERC)
Over the past decades, advances in ultrafast technologies led to the production of intense ultrashort THz to optical pulses reaching single-cycle pulse duration. Using such pulses for electron acceleration offers advantages in terms of higher thresholds for materials breakdown, thus introducing a promising path towards increasing acceleration gradients. Conventional accelerator technology is based on either continuous wave or long pulse operation, where resonant or guiding structures are usually employed. We introduce novel structures for electron acceleration which operate with single-cycle pulses named as single-cycle ultrafast guns. The operating frequencies considered here are at THz wavelengths inspired by the recent progress in the optical generation of intense single-cycle THz pulses. We begin with designing guns for low energy pulses and proceed with structures designed for high energy pulses. More importantly, it is shown that the already achieved THz pulse energies of 20 uJ are enough to realize relativistic fields for electron acceleration. These structures will underpin future devices for fabricating miniaturized electron guns and linear accelerators.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY015

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMY017

Laser Driven Dielectric Accelerator in the Non-relativistic Energy Region

laser, acceleration, radiation, vacuum

1585

K. Koyama, M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
S. Kurimura
NIMS, Ibaraki, Japan
H. Okamoto, S. Otsuki
The University of Tokyo, Tokyo, Japan
M. Yoshida
KEK, Ibaraki, Japan

Laser-driven dielectric accelerator (LDA) is suitable for delivering a submicron-size ultra-short electron beam, which is useful for studying basic processes of the radiation effect in a biological cell. Both the oblique incidence and the normal incidence configurations of LDA were studied. The oblique incidence configuration of LDA relaxes the synchronization condition as v_e=¥pm c L_G/¥left(¥λ+ L_G n ¥sin ¥theta ¥right) and is somewhat suitable for accelerating the non-relativistic electrons. The required energy to accelerate electrons in the oblique incidence configuration is smaller than that in the normal incidence configuration by a factor of ¥cos ¥theta, where ¥theta is the incidence angle of the laser beam. Two gratings each were made of different material structure of silica ({¥rm SiO₂}) were fabricated by the electron beam lithography. When a crystal silica was adopted, many large humps of several hundred nm size were observed in grooves of the grating. On the other hand, a glass silica had smoother grooves.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY017

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMY018

Recent Progress of Proton Acceleration at Peking University

laser, ion, target, plasma

1588

Q. Liao, Y.X. Geng, C. Lin, H.Y. Lu, W.J. Ma, X.Q. Yan, Y.Y. Zhao
PKU, Beijing, People's Republic of China

We study the enhanced laser ion acceleration using near critical density plasma lens attached to the front of a solid target. The laser quality is spontaneously improved by the plasma lens and energy density of hot electrons is greatly increased by the direct laser acceleration mechanism. Both factors will induce stronger sheath electric field at the rear surface of the target, which accelerates ions to a higher energy. Particle-in-cell simulations show that proton energy can be increased 2-3 times compared with single solid target. This result provides the opportunities for applications of laser plasma accelerator, such as cancer therapy. Further experiments will soon be carried out on 200 TW laser acceleration system at Peking University.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY018

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMY024

First Test of The Imperial College Gabor (Plasma) Lens prototype at the Surrey Ion Beam centre

plasma, proton, background, ion

1598

P.A. Posocco, J.K. Pozimski, Y. Xia
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
M.J. Merchant
UoM ICS, Manchester, United Kingdom
M.J. Merchant
The Christie NHS Foundation Trust, Manchester, United Kingdom

Funding: Funding was provided by the Imperial College Confidence in Concepts scheme.
The first plasma (Gabor) lens prototype operating at high electron density was built by the Imperial College London in 2015. In November 2015 the lens was tested at the Ion Beam Centre of the University of Surrey with a 1 MeV proton beam. Over 500 snapshots of the beam hitting a scintillator screen installed 0.5 m downstream of the lens were taken for a wide range of settings. Unexpectedly, instead of over- or underfocusing the incoming particles, the lens converted pencil beams into rings. In addition to the dependence of their radius on the lens settings, periodic features appeared along the circumference, suggesting that the electron plasma was exited into a coherent off-axis rotation. The cause of this phenomenon is under investigation.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY024

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMY025

Proton-Driven Electron Acceleration in Hollow Plasma

plasma, proton, acceleration, wakefield

1601

Y. M. Li, K. Hanahoe, O. Mete Apsimon, T.H. Pacey, G.X. Xia
UMAN, Manchester, United Kingdom

Funding: President's Doctoral Scholar Award from The University of Manchester.
Proton driven plasma wakefield acceleration has been proposed to accelerate electrons to TeV-scale in a single hundreds of meters plasma section. However, it is difficult to conserve beam quality due to the positively charged driven scheme. In this paper, we demonstrate via simulation that hollow plasma is favourable to maintain the long and stable acceleration and simultaneously be able to achieve low normalized emittance and energy spread of the witness electrons. Moreover, it has much higher beam loading tolerance compared to the uniform case. This will potentially facilitates the acceleration of a large number of particles with high beam quality.
* Caldwell A et al.Nature Physics, 2009, 5(5): 363-367
** K. Lotov, Phys. Rev. ST Accel. Beams, 2010, 13(4): 041301.
*** W. Kimura et al., Phys. Rev. ST Accel. Beams, 2011, 14(4): 041301.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY025

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMY026

Electron Beam Generation and Injection From a Pyroelectric Crystal Array

acceleration, laser, injection, radiation

1604

R.B. Yoder, Z. Kabilova, B. Saeks
Goucher College, Baltimore, Maryland, USA

Novel acceleration structures (e.g. dielectric laser accelerators [DLAs]*) powered by lasers have the potential to greatly reduce the footprint and cost of both industrial linacs and colliders. As these devices have dimensions comparable to optical wavelengths, they require injection of a sub-micron-scale electron bunch to generate high-quality output beams, which are well beyond the capability of conventional rf photocathodes. Photoexcitation and field emission from an array of nanotips, followed by further acceleration and focusing, is a promising approach to achieving the requisite small beam sizes for successful injection. Pyroelectric crystals can provide electrostatic fields of sufficient magnitude and uniformity to enable emission and acceleration. We present an initial design for a low-energy injection module using the accelerating electrostatic fields provided by pyroelectric crystals. The approach is modeled numerically and supported by direct benchtop measurements of pyroelectric fields from a 2-crystal array.
*R. J. England et al., Rev. Mod. Phys. 86, p. 1337 (2014).

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY026

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMY028

Ultra-high Gradient Acceleration in Nano-crystal Channels

plasma, laser, acceleration, wakefield

1607

Y.-M. Shin
Northern Illinois University, DeKalb, Illinois, USA
D.M. Farinella, P. Taborek, T. Tajima
UCI, Irvine, California, USA
A.H. Lumpkin, V.D. Shiltsev, R.M. Thurman-Keup
Fermilab, Batavia, Illinois, USA
X. Zhang
Shanghai Institute of Optics and Fine Mechanics, Shanghai, People's Republic of China

Funding: This work was supported by the DOE contract No.DEAC02-07CH11359 to the Fermi Research Alliance LLC. We also thank the FAST Department team for the helpful discussions and technical support.
Crystals behave like a non-equilibrium medium (e.g. plasma), but at a relatively low temperature, if heated by a high-power driving source. The warm dense matter contains many more ions (n0 ~ 10¹⁹ - 10²³ cm^-3) available for plasma acceleration than gaseous plasmas, and can possibly support electric fields of up to 30 TV/m of plasma oscillation*,**,***,****. Atomic lattice spaces in solid crystals are known to consist of 10 - 100 V/Å potential barriers capable of guiding and collimating high energy particles with continuously focused acceleration. Nanostructured crystals (e.g. carbon nanotube) with dimensional flexibilities can accept a few orders of magnitude larger phase-space volume of channeled particles than natural crystals. Our PIC simulation results*****, ****** obtained from two plasma acceleration codes, VORPAL and EPOCH, indicate that in the linear regime the beam-driven and laser-driven electrons channeled in a 100 micro-meter long effective nanotube gain 10 MeV (G = 1 - 10 TeV/m). Experimental tests, including slit-mask beam modulation and pump-probe electron diffraction, are designed in Fermilab and NIU to identify a wakefield effect in a photo-excited crystal.
* Phys. Rev.Lett. 43, 267(1979)
** Phys. Plasmas 15, 103105(2008)
*** Nature Photonics 9, 274(2015)
**** Phys. J. 223, 1037(2014)
***** Appl. Phys. Lett. 105, 114106(2014)
****** Phys. Plasmas 20, 123106(2013)

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY028

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMY030

Measurements of Transmitted Electron Beam Extinction through Si Crystal Membranes

emittance, scattering, laser, experiment

1611

E.A. Nanni, R.K. Li, C. Limborg, X. Shen, S.P. Weathersby
SLAC, Menlo Park, California, USA
W.S. Graves, R. Kirian, J. Spence, U. Weierstall
Arizona State University, Tempe, USA

A recently proposed method for the generation of relativistic electron beams with nanometer-scale current modulation requires diffracting relativistic electrons from a perfect crystal Si grating, accelerating the diffracted beam and imaging the crystal structure into the temporal dimension via emittance exchange. The relative intensity of the current modulation is limited by the ability to extinguish the transmitted beam via diffraction with a single-crystal Si membrane. In these preliminary experiments we will measure the extinction of the transmitted electron beam at zero scattering angle due to multiple Bragg scattering from a Si membrane with a uniform thickness of 340 nm at 2.35 MeV using the SLAC UED facility. The impact of beam divergence and charge density at the Si target will be quantified. The longevity of the Si membrane will also be investigated by monitoring the diffraction pattern as a function of time to observe the potential onset of damage to the crystal.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY030

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMY032

Radiation from Open Ended Waveguide with a Dielectric Loading

radiation, vacuum, controls, simulation

1617

S.N. Galyamin, A.A. Grigoreva, A.V. Tyukhtin, V.V. Vorobev
Saint-Petersburg State University, Saint-Petersburg, Russia
S. Baturin
LETI, Saint-Petersburg, Russia
S. Baturin
Euclid TechLabs, LLC, Solon, Ohio, USA

Funding: Work is supported by the Grant of the President of Russian Federation (No. 6765.2015.2) and the Grants from Russian Foundation for Basic Research (No. 15-32-20985, 15-02-03913).
Terahertz radiation is considered as a promising tool for a number of applications. One possible way to emit THz waves is to pass short electron bunch through a waveguide structure loaded with dielectric*. In our previous papers, we have analyzed this problem in both approximate** and rigorous*** formulation. However, we have encountered certain difficulties with calculations. In the present report, we are starting to develop another rigorous approach based on mode-matching technique and modified residue-calculus technique. We consider the radiation from the open-ended dielectrically loaded cylindrical waveguide placed inside regular cylindrical waveguide with larger radius. We present structure of reflected and transmitted modes and typical radiation patterns from the open end of larger radius waveguide.
* S. Antipov et al., Appl. Phys. Lett., vol. 100, p. 132910, 2012.
** S.N. Galyamin et al., Opt. Express, vol. 22, No. 8, p. 8902, 2014.
*** S.N. Galyamin et al., in Proc. IPAC'15, pp. 2578-2580.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY032

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMY042

Proton Injection into the Fermilab Integrable Optics Test Accelerator (IOTA)

rfq, proton, optics, ion-source

1638

E. Prebys, K. Carlson, H. Piekarz, A. Valishev
Fermilab, Batavia, Illinois, USA
S. A. Antipov
University of Chicago, Chicago, Illinois, USA

Funding: This work is supported by the DOE, under Contract No. De-AC02-07CH11359.
The Integrable Optics Test Accelerator (IOTA) is an experimental synchrotron being built at Fermilab to test the concept of non-linear "integrable optics". These optics are based on a lattice including non-linear elements that satisfies particular conditions on the Hamiltonian. The resulting particle motion is predicted to be stable but without a unique tune. The system is therefore insensitive to resonant instabilities and can in principle store very intense beams, with space charge tune shifts larger than those which are possible in conventional linear synchrotrons. The ring will initially be commissioned with electrons, but this poster describes progress toward the injection of protons into the ring, using the RFQ originally built for the High Energy Neutrino Source (HINS) project.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY042

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOR001

Lifetime Improvements with a Harmonic RF System for the ESRF EBS

impedance, cavity, storage-ring, simulation

1644

N. Carmignani, L. Farvacque, J. Jacob, S.M. Liuzzo, B. Nash, T.P. Perron, P. Raimondi, R. Versteegen, S.M. White
ESRF, Grenoble, France

A third-harmonic RF system to increase the Touschek lifetime is under study for the European Synchrotron Radiation Facility (ESRF) Extremely Brilliant Source (EBS) storage ring, in particular for modes with high current per bunch. Multi-particle simulations have been done to study the bunch lengthening and shape in presence of inductive impedance and a third-harmonic RF system.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR001

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOR002

Residual Ion Dynamics in ThomX Electron Storage Ring

ion, storage-ring, focusing, dipole

1648

A.R. Gamelin, C. Bruni
LAL, Orsay, France

Funding: Work is supported by ANR-10-EQPX-51, by grants from Région Ile-de-France, IN2P3 and Pheniics Doctoral School.
ThomX is a compact Compton Backscattering Source (CBS) which is being built in Orsay, France. Ions produced from residual gas in the storage ring can induce several instabilities. However the electron beam stability is crucial to attain the nominal performances foreseen. In order to prevent instabilities ion cleaning is considered. Complete studies of the beam effect on the ions have been undertaken. It shows that there are preferential ion accumulation points depending on the storage ring lattice. This paper will detail the ion longitudinal and transverse dynamics considering the optics of ThomX storage ring.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR002

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOR003

CSR-Driven Longitudinal Single Bunch Instability with Negative Momentum Compaction Factor

synchrotron, shielding, damping, radiation

1651

P. Kuske
HZB, Berlin, Germany

Acceptable agreement is found between experimental results obtained at the Metrology Light Source (MLS) operated with negative momentum compaction factor, α, and theoretical estimates of the CSR-driven threshold currents. Theoretical instability thresholds are estimated by numerically solving the Vlasov-Fokker-Planck equation and/or by multi particle tracking and taking into account the shielded CSR-interaction. Some of the issues with the calculations, the determination of the theoretical thresholds as well as the derivation of a general scaling law will be presented

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR003

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOR006

Systematic Studies of Short Bunch-Length Bursting at ANKA

radiation, synchrotron, shielding, synchrotron-radiation

1662

M. Brosi, E. Blomley, E. Bründermann, N. Hiller, B. Kehrer, A.-S. Müller, M. Schedler, M. Schuh, P. Schönfeldt, J.L. Steinmann
KIT, Karlsruhe, Germany

Funding: Supported by the German Federal Ministry of Education and Research (05K13VKA), the Helmholtz Association (VH-NG-320) and by the Helmholtz International Research School for Teratronics (HIRST).
At ANKA, the Karlsruhe synchrotron radiation source, the so called short bunch-length operation mode allows the reduction of the bunch length down to a few picoseconds. The micro-bunching instability resulting from the high degree of longitudinal compression leads to fluctuations in the emitted intensity in the THz regime, referred to as bursting. For extremely compressed bunches at ANKA bursting also occurs, in a certain current range, below the main bursting threshold. This contribution shows measurements of this short bunch-length bursting and makes first comparisons with theory.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR006

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOR012

THz Coherent Synchrotron Radiation from Ultra-low Alpha Operating Mode at Diamond Light Source

simulation, storage-ring, radiation, impedance

1682

T. Chanwattana, M. Atay, R. Bartolini
JAI, Oxford, United Kingdom
R. Bartolini, G. Cinque, M. Frogley, E. Koukovini-Platia, I.P.S. Martin
DLS, Oxfordshire, United Kingdom

Diamond Light Source is regularly operated in low-alpha mode to provide THz coherent synchrotron radiation (CSR) and short X-ray pulses for users. In order to maintain the wide frequency range of the coherent radiation whilst improving the signal to noise ratio, an ultra-low alpha mode has been considered to shorten the bunch length even further. In order to study this mode, the analysis of single bunch dynamics resulting from a variety of wakefield sources has been investigated using a single bunch multiparticle tracking code. These results are compared with measurements recorded using a Fourier transform infrared (FTIR) interferometer on the MIRIAM beam-line at Diamond.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR012

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOR018

Design Optimization of Compensation Chicanes in the LCLS-II Transport Lines

simulation, FEL, space-charge, undulator

1695

J. Qiang, C.E. Mitchell, M. Venturini
LBNL, Berkeley, California, USA
Y. Ding, P. Emma, Z. Huang, G. Marcus, Y. Nosochkov, T.O. Raubenheimer, L. Wang, M. Woodley
SLAC, Menlo Park, California, USA

LCLS-II is a 4th-generation high-repetition rate Free Electron Laser (FEL) based x-ray light source to be built at the SLAC National Accelerator Laboratory. To mitigate the microbunching instability, the transport lines from the exit of the Linac to the undulators will include a number of weak compensation chicanes with the purpose of cancelling the momentum compaction generated by the main bend magnets of the transport lines. In this paper, we will report on our design optimization study of these compensation chicanes in the presence of both longitudinal and transverse space-charge effects.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR018

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOR019

RF Injector Beam Dynamics Optimization and Injected Beam Energy Constraints for LCLS-II

cavity, laser, emittance, gun

1699

C.E. Mitchell, H.J. Qian, J. Qiang, F. Sannibale, M. Venturini
LBNL, Berkeley, California, USA
P. Emma, T.O. Raubenheimer, J.F. Schmerge, F. Zhou
SLAC, Menlo Park, California, USA

Funding: Work supported by the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231.
LCLS-II is a proposed high-repetition rate (>1 MHz) Free Electron Laser (FEL) X-ray light source, based on a CW, superconducting linac, to be built at SLAC National Accelerator Laboratory. The injector technology is based on a high-repetition rate RF photoinjector gun developed as part of the Advanced Photoinjector Experiment (APEX) at Lawrence Berkeley National Laboratory. Exploration of the injector design settings is performed using a multiobjective genetic optimizer to optimize the beam quality at the injector exit (~100 MeV). In this paper, we describe the current status of LCLS-II injector design optimization, with a focus on the sensitivity of the optimized solutions to the beam energy at the injector exit, which is constrained by the requirements of the downstream laser heater system.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOR020

Combination of Density and Energy Modulation in Microbunching Analysis

collective-effects, synchrotron-radiation, radiation, synchrotron

1703

C.-Y. Tsai
Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
R. Li
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Microbunching instability (MBI) has been one of the most challenging issues in the transport of high-brightness electron beams for modern recirculating or energy recovery linac machines. Recently we have developed and implemented a Vlasov solver* to calculate microbunching gain for an arbitrary beamline lattice design, based on the extension of early theoretical formulation** for the microbunching amplification from an initial density perturbation to the final density modulation. For more thorough analyses, in addition to the case of (initial) density to (final) density amplification, we in this paper extend the previous formulation to more general cases, including energy-to-density, density-to-energy and energy-to-energy amplifications for a recirculation machine. Such semi-analytical formulae are then incorporated into our Vlasov solver, and reasonable agreement is obtained when the semi-analytical results are benchmarked with particle tracking simulation using ELEGANT***.
* C.Y. Tsai et al, FEL'15
** S. Heifets et al, PRSTAB 5, 064401 (2002), Z. Huang and K. Kim, PRSTAB 5, 074401 (2002), M. Vneturini, PRSTAB 10, 104401 (2007)
*** M. Borland, APS LS-287, 2000

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR020

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOR021

Incoherent Vertical Emittance Growth from Electron Cloud at CesrTA

simulation, dipole, emittance, positron

1707

S. Poprocki, J.A. Crittenden, S.N. Hearth, J.D. Perrin, D. L. Rubin, S. Wang
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Work supported by the US National Science Foundation PHY-1416318, PHY-0734867, and PHY-1002467, and the U.S. Department of Energy DE-FC02-08ER41538
We report on measurements of electron cloud (EC) induced tune shifts and emittance growth at the Cornell Electron-Positron Storage Ring Test Accelerator (CesrTA) with comparison to tracking simulation predictions. The simulations are based on a weak-strong model of the interaction of the positron beam (weak) with the electron cloud (strong), using electric fields computed with established EC buildup simulation codes (ECLOUD). Experiments were performed with 2.1 GeV positrons in a 30 bunch train with 14 ns bunch spacing and 9 mm bunch length, plus a witness bunch at varying distance from the train to probe the cloud as it decays. Measurements of the horizontal and vertical coherent tune shifts and horizontal and vertical bunch size were obtained for a range of train and witness bunch currents, and compared to simulations.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOR026

Final Design and Status of the Third Recirculation for the S-DALINAC*

recirculation, dipole, linac, operation

1717

M. Arnold, T. Kürzeder, N. Pietralla
TU Darmstadt, Darmstadt, Germany
F. Hug
IKP, Mainz, Germany

Funding: *Work supported by DFG through CRC 634 and RTG 2128
Since 1991 the twice-recirculating superconducting accelerator S-DALINAC is providing electron beams for nuclear physics experiments. Due to a reduced quality factor of its cavities in comparison to their design values it was not possible to operate the accelerator with its maximum design energy of 130 MeV in cw mode. To provide electron beams of this energy in the future it was decided to add one recirculation beam line in order to use the main linac four times, operating the cavities on decreased accelerating gradients. The necessary modifications consist of several different aspects: A new beamline needs to be installed and other pre-existing beam line sections have to be modified for matching new boundary conditions. These new conditions are mainly a result of beam dynamics simulations and of the design of a new separation dipole magnet, which will bend the different beams energy-dependent in the various recirculation beam lines. We will present the implemented design and give a status report on the project.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR026

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOR027

Interaction of RF Phase Modulation and Coupled-Bunch Instabilities at the DELTA Storage Ring

damping, storage-ring, feedback, synchrotron

1720

M. Sommer, B.D. Isbarn, B. Riemann, T. Weis
DELTA, Dortmund, Germany

Funding: Work supported by the BMBF under contract no. 05K13PEB.
Analyzing the interaction of RF phase modulation and coupled-bunch instabilities requires a method to determine damping rates of coupled-bunch modes at presence of RF phase modulation. This paper shows, that the common way of using exponential fits to determine damping rates is not viable for high modulation amplitudes. It presents a new method, which is capable of acquiring damping rates of coupled-bunch modes for phase shifts up to 5°, using a bunch-by-bunch feedback system. For this purpose a specific mode is excited by the feedback system and the saturation value, i.e. the maximum excitation, is measured to calculate the damping rate. With this new method, the modulation amplitude of the RF phase modulation is swept from 0° to 5° and it can be shown, that the damping rate is proportional to the square of the modulation amplitude.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR027

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOR029

Study of Fast Instability in Fermilab Recycler

simulation, dipole, betatron, proton

1728

S. A. Antipov
University of Chicago, Chicago, Illinois, USA
P. Adamson, S. Nagaitsev, M.-J. Yang
Fermilab, Batavia, Illinois, USA

One of the factors which may limit the intensity in the Fermilab Recycler is a fast transverse instability. It develops within a hundred turns and, in certain conditions, may lead to a beam loss. Various peculiar features of the instability: its occurrence only above a certain intensity threshold, and only in horizontal plane, as well as the rate of the instability, suggest that its cause is electron cloud. We studied the phenomena by observing the dynamics of stable and unstable beam. We found that beam motion can be stabilized by a clearing bunch, which confirms the electron cloud nature of the instability. The findings suggest electron cloud trapping in Recycler combined function mag-nets. Bunch-by-bunch measurements of betatron tune show a tune shift towards the end of the bunch train and allow the estimation of the density of electron cloud and the rate of its build-up. The experimental results are in agreement with numerical simulations of electron cloud build-up and its interaction with the beam.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR029

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOR030

Design of Octupole Channel for Integrable Optics Test Accelerator

octupole, optics, simulation, dynamic-aperture

1731

S. A. Antipov
University of Chicago, Chicago, Illinois, USA
K. Carlson, A. Valishev, S.J. Wesseln
Fermilab, Batavia, Illinois, USA
R. Castellotti
SSSUP, Pisa, Italy

We present the design of octupole channel for Integrable Optics Test Accelerator (IOTA). IOTA is a test accelerator at Fermilab, aimed to conduct research towards high-intensity machines. One of the goals of the project is to demonstrate high nonlinear betatron tune shifts while retaining large dynamic aperture in a realistic accelerator design. At the first stage the tune shift will be attained with a special channel of octupoles, which creates a variable octupole potential over a 1.8 m length. The channel consists of 18 identical air-cooled octupole magnets. The magnets feature a simple low-cost design, while meeting the requirements on maximum gradient - up to 1.4 kG/cm³, and field quality - strength of harmonics below 1%. Numerical simulations show that the channel is capable of producing a nonlinear tune shift of 0.08 without restriction of dynamic aperture of the ring.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR030

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW002

Current Status of the Milliampere Booster for the Mainz Energy-recovering Superconducting Accelerator

simulation, experiment, linac, gun

1741

R.G. Heine, K. Aulenbacher, L.M. Hein, C. Matejcek
IKP, Mainz, Germany

Funding: Work supported by German Science Foundation (DFG) under the Cluster of Excellence "PRISMA" EXC1098/2014
The Milliampere Booster (MAMBO) is the injector linac for the Mainz Energy-recovering Superconducting Accelerator MESA. The MESA facility is currently under design at the Institut für Kernphysik (KPH) at Johannes Gutenberg University of Mainz (JGU). In this paper we will present the current design status of the linac.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW002

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW004

Status of the STAR Project

laser, focusing, controls, vacuum

1747

A. Bacci, I. Drebot, L. Serafini, V. Torri
Istituto Nazionale di Fisica Nucleare, Milano, Italy
R.G. Agostino, R. Barberis, M. Ghedini, F. Martire, C. Pace
UNICAL, Arcavacata di Rende, Italy
D. Alesini, M. Bellaveglia, J.J. Beltrano, F.G. Bisesto, G. Borgese, B. Buonomo, G. Di Pirro, G. Di Raddo, A. Esposito, A. Gallo, A. Ghigo, F. Iungo, L. Pellegrino, A. Stella, C. Vaccarezza
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
INFN-Roma II, Roma, Italy
G. D'Auria, A. Fabris, M. Marazzi
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
V. Petrillo
Universita' degli Studi di Milano, Milano, Italy
E. Puppin
Politecnico/Milano, Milano, Italy
M. Rossetti Conti
Universita' degli Studi di Milano & INFN, Milano, Italy

This paper reports on the final design and the work in progress on the STAR project (IPAC2014:WEPRO115), which is under construction at the Univ. of Calabria (Italy). The project is devoted to the construction of an advanced Thomson source of monochromatic tunable, ps-long, polarized X-ray beams, ranging from 40 up to 140 KeV . At present the buildings and main plants have been completed as the acquisition of main components: the RF photo-injector, the accelerating section, laser systems for collision and photo-cathode, RF Power Source and magnets are ready to start installation and site acceptance tests. The design of laser lines is complete and simulated by ZEMAX, aiming to minimize energy losses, optical distortions and providing a tunable experimental setup as well. The RF power network is close to be tested, it's based on a 55MW (2.5us pulse) S-band Klystron driven by a 500kV Pulse Forming Network based modulator and a Low Level RF system, running at 100 Hz. The Control System is been designed using EPICS and allows to manage easily and fastly each machine parameter. We expect to start commissioning the machine by the end of 2016 and obtain the first collisions within the first part of 2017.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW004

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW006

Six-dimensional Phase-space Rotation and its Applications

emittance, FEL, cathode, simulation

1754

M. Kuriki, K. Negishi
HU/AdSM, Higashi-Hiroshima, Japan
H. Hayano, R. Kato, K. Ohmi, M. Satoh, Y. Seimiya, J. Urakawa
KEK, Ibaraki, Japan
S. Kashiwagi
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

Funding: This work is partly supported by Grant-in-Aid for Scientific Research by MEXT, Japan (KAKENHI) 25390126.
Recent progress on the accelerator science requires optimized phase space distributions of the beam for each applications. A classical approach to satisfy the requirements is minimizing the beam emittance with a bunch charge as much as possible. This classical approach is not efficient and not compatible to the beam dynamics nature. 6D phase-space rotation, e.g. z-x and x-y, gives a way to optimize the phase space distribution for various applications. In this article, we discus possible applications of the 6D phase space rotation. The x-y rotation generates the high aspect ratio beam for linear colliders directly without DR (Damping Ring). Combination of bunch clipping with a mechanical slit and x-z rotation can generate micro-bunch structure which is applicable for FEL enhancement and drive beam for dielectric acceleration. We present our theoretical and simulation study on these applications.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW006

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW008

Generation of Short Bunch Electron Beam from Compact Accelerator for Terahertz Radiation

laser, radiation, injection, detector

1757

S. Suphakul, T. Kii, K. Masuda, K. Morita, H. Ohgaki, K. Torgasin, H. Zen
Kyoto University, Kyoto, Japan

We are developing a new compact accelerator system to generate a high power terahertz (THz) radiation at the Institute of Advanced Energy, Kyoto University. THz radiations are produced by injecting ultra-short and intense electron pulses to a short plannar undulator. The bunch compression characteristic by the newly installed chicane was investigated by observation of a coherent part of an optical transition radiation (OTR). As the result, the chicane can compress the electron bunch at the laser injection phase from 10 to 40 degree. The beam energy and relative rms energy spread were also measured and the results were 4.6 MeV and 1.3 %, respectively.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW008

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW009

Generation of Coherent Undulator Radiation using Extremely Short Electron Bunch at t-ACTS, Tohoku University

radiation, undulator, bunching, injection

1760

S. Kashiwagi, T. Abe, H. Hama, F. Hinode, T. Muto, I. Nagasawa, K. Nanbu, H. Saito, Y. Shibasaki, K. Takahashi, C. Tokoku
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

An accelerator test facility, t-ACTS, was established at Research Center for Electron Photon Science, Tohoku University, in which an intense coherent terahertz (THz) radiation is generated from an extremely short electron bunch. Velocity bunching scheme in a traveling-wave accelerating structure is employed to produce the short electron bunch, and a production of sub-picosecond electron bunch was demonstrated. A long-period linear undulator, which has 25 periods with a period length of 10 cm and a peak magnetic field of 0.41 T, has been developed to produce intense coherent THz radiation. Properties of the radiation from the THz undulator such as radiation fields, spectrum and angular distribution were numerically investigated based on the parameters of short electron bunch and THz undulator. By optimization of bunch compression, it is possible to extract a coherent radiation of fundamental mode excluding higher-order mode. The detail of the numerical studies for the coherent undulator radiation will be reported in the conference.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW009

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW010

Production of Ultra-short Electron Pulse and Observation of Coherent Transition Radiation at t-ACTS, Tohoku University

radiation, bunching, detector, injection

1763

T. Abe, H. Hama, F. Hinode, S. Kashiwagi, T. Muto, I. Nagasawa, K. Nanbu, H. Saito, Y. Shibasaki, K. Takahashi, C. Tokoku
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

A test-Accelerator as Coherent Terahertz Source (t-ACTS) project has been under development at Research Center for Electron Photon Science, Tohoku University. In order to generate a coherent radiation in terahertz (THz) region, it is necessary to produce sub-picosecond electron pulses. Velocity bunching scheme is employed for the short electron pulse production in t-ACTS. We experimentally confirmed the production of short electron pulse under 500 fs by measuring the bunch length using a streak camera. Coherent transition radiation in THz region was produced by which the short electron pulses pass through a vacuum-metal interface. Several radiation properties including　spatial distribution, polarization and spectrum were measured and compared with theoretical calculations. The details of the beam experiment at t-ACTS are described.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW010

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW011

Profile Measurements of Bremsstrahlung Gamma-Rays from Tungsten Plates for Radioactive Isotope Production via Photonuclear Reaction using a 60 MeV Electron Linac

quadrupole, detector, simulation, emittance

1766

K. Takahashi, H. Hama, F. Hinode, S. Kashiwagi, H. Kikunaga, T. Muto, I. Nagasawa, K. Nanbu, Y. Shibasaki, T. Suda, C. Tokoku, K. Tsukada
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

Radioactive isotopes have been produced via photo-nuclear reaction using a 60 MeV high-power electron linac for research fields of nuclear chemistry and radioac-tive analysis at Research Center for Electron Photon Science (ELPH), Tohoku University. The electron beam with an average current more than 100 μA is transported to an electron-bremsstrahlung gamma-ray converter of 2 mm thickness platinum or tungsten plate at the irradiation station. A target of 10 mm diameter is placed 3 cm behind a converter. It is enclosed with a quartz glass in the water cooling system and is irradiated for photonuclear reaction. Since the correlation between the spatial profile of bremsstrahlung gamma-rays at the target position and accelerator parameters is of our primary interest, nickel thin films are irradiated and the profiles of bremsstrahlung gamma-rays are measured by intensity distribution measurements of 57Ni radioactivity using the phosphorus imaging plate. In the meantime, the beam emittance and Twiss parameters are measured.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW011

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW014

Simulation of High Resolution Field Emission Imaging in an rf Photocathode Gun

cathode, gun, solenoid, simulation

1769

J.H. Shao, H.B. Chen, J. Shi, X.W. Wu
TUB, Beijing, People's Republic of China
S.P. Antipov, C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
W. Gai
ANL, Argonne, Illinois, USA
F.Y. Wang
SLAC, Menlo Park, California, USA

Precisely locating field emission (FE) emitters on a realistic surface in rf structures is technically chal-lenging in general due to the wide emitting phase and the broad energy spread. A method to achieve in situ high resolution FE imaging has been proposed by using solenoids and a collimator to select electrons emitted at certain phases. The phase selection criterion and imaging properties have been studied by the beam dynamics code ASTRA. Detailed results are presented in this paper.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW014

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW015

Experiment of High Resolution Field Emission Imaging in an rf Photocathode Gun

cathode, experiment, gun, background

1772

J.H. Shao, H.B. Chen, J. Shi, X.W. Wu
TUB, Beijing, People's Republic of China
S.P. Antipov, S.V. Baryshev, C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
M.E. Conde, W. Gai, G. Ha, E.E. Wisniewski
ANL, Argonne, Illinois, USA
F.Y. Wang
SLAC, Menlo Park, California, USA

The first in situ high resolution field emission (FE) imaging experiment has been carried out on an L-band photocathode gun test stand at Argonne Wakefield Accelerator facility (AWA). Separated strong emitters have been observed to dominate the field emission. Field enhancement factor, beta, of small regions on the cathode has been measured with the imaging system. It is shown that most strong emitters overlaps with the high beta regions. The post surface examinations reveal the origins of ~75% strong emitters overlap with the spots where rf breakdown have occurred. Detailed results are presented in this paper.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW015

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW017

Twin Bunches at the FACET-II

wakefield, simulation, acceleration, controls

1778

Z. Zhang
TUB, Beijing, People's Republic of China
M.J. Hogan, Z. Huang, A. Marinelli
SLAC, Menlo Park, California, USA

Twin electron bunches, generated, accelerated and compressed in the same acceleration bucket, have attracted a lot of interest in the free-electron lasers and wakefield acceleration. The recent successful experiment at the LCLS used twin bunches to generate two-color two x-ray pulses with tunable time delay and energy separation. In this note, we apply the twin bunches to the plasma wakefield acceleration. Numerical simulations show that based on the beamline of the FACET-II, we can generate high-intensity two electron bunches with time delay from ∼ 100 fs to picoseconds, which will benefit the control of high-gradient witness bunch acceleration in a plasma.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW017

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW018

Tunable High-Intensity Electron Bunch Train Production Based on Nonlinear Longitudinal Space Charge Oscillation

radiation, experiment, space-charge, gun

1782

Z. Zhang, H.B. Chen, Y.-C. Du, W.-H. Huang, J. Shi, X.L. Su, C.-X. Tang, Q.L. Tian, D. Wang, W. Wang, L.X. Yan, L.M. Zheng, Z. Zhou
TUB, Beijing, People's Republic of China
W. Gai
ANL, Argonne, Illinois, USA

High peak current electron bunch trains with tunable terahertz (THz) spacing are produced and measured experimentally. An initial picosecond periodic modulation in the temporal profile of a relativistic electron beam is magnified by the longitudinal space charge forces. As opposed to trying to reduce its smearing effect for large beam current, we take advantages of the nonlinear space charge oscillation through controlling the plasma phase advance. The spacing of the bunch train can be varied continuously either by tuning the velocity bunching of a radio-frequency gun or by tuning the compression of a downstream magnetic chicane. The narrow-band μJ-level THz radiation from the bunch train are also measured with tunable central frequency of the spectral from ~0.5 THz to 1.6 THz. The bunch train measurements are consistent with the particle tracking simulations.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW018

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW019

Preliminary Concept of Fast Positron Source Based on Photo-injector

positron, target, simulation, linac

1785

Z. Chu, J.G. Guo, Q. Luo, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: Supported by National Natural Science Foundation of China (11375178 and 11575181) and the Fundamental Research Funds for the Central Universities, Grant No WK2310000046
Based on the past experience in slow positron beam, researchers at NSRL/USTC proposed a fast positron source for detection of material deep tiny flaws. Different from conventional positron sources used in positron annihilation techniques, the planned positron source will be a positron production linac, similar to positron injectors used in colliders. To compress the positron pulse, the bombarding electron beam comes from a short bunch photo-injector. A computer simulation was performed using EGS4 and PARMELA code. The bombarding electron bunch is 300pC, with an energy of 30MeV. Simulations results showed that it is reasonable to expect a beam of more than 10⁵ positrons per pulse for future positron annihilation studies. Further work is to be done to achieve precise control of beam energy.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW022

Hybrid Electron Linac With Standing and Travelling Wave Accelerating Sections

focusing, linac, impedance, coupling

1791

S.V. Matsievskiy, A.V. Bulanov, V.I. Kaminskiy, E.A. Savin, N.P. Sobenin
MEPhI, Moscow, Russia
R.Yu. Alekhanov
NRNU, Moscow, Russia

Hybrid electron linacs with standing and travelling wave accelerating sections are not well described in literature. Limited number of studies have shown that application of these systems makes it possible to develop a compact linac with high efficiency and simpler power system. Typically, these systems use well-studied bi-periodical accelerating structure (BAS) cells for a standing wave section and disc-loaded waveguides (DLW) for a traveling wave section. This paper describes the development of such system using DLW cells with magnetic coupling (DLW-M). Here BAS appears as an absorbing load connected to the DLW-M accelerating structure by rectangular waveguide allowing to have theoretical zero reflection at RF input. Such system also provides possibility of plain beam output energy adjustment. Studies of the structure were carried out using equivalent circuits methods and numerical 3D-modeling. Beam dynamics was calculated.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW022

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW023

New 10 MeV High-power Electron Linac for Industrial Application

linac, coupling, simulation, bunching

1794

S.M. Polozov, D.S. Bazyl, T.V. Bondarenko, M. Gusarova, Yu.D. Kliuchevskaia, M.V. Lalayan, V.I. Rashchikov, E.A. Savin
MEPhI, Moscow, Russia
M.I. Demsky, A.A. Eliseev, V.V. Krotov, D.E. Trifonov
CORAD Ltd., St. Petersburg, Russia
B.S. Han, W.G. Kang, H.G. Park
EB TECH Co. Ltd., Daejeon, Republic of Korea

Joint team of CORAD and MEPhI developed a new industrial accelerating structure for average beam power up to 20 kW and energy range from 7.5 to 10 MeV. The use of modern methods and codes for beam dynamics simulation, raised coupling coefficient and group velocity of SW biperiodic accelerating structure allowed to reach high pulse power utilization and obtain high efficiency. Gentle buncher provides high capturing coefficient and narrow energy spectrum. The first linear accelerator with this structure was constructed and tested in collaboration with the company EB Tech.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW023

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW024

Compact Standing Wave Electron Linac with the Hybrid Accelerating and Power Generation Cell

coupling, cavity, Windows, linac

1797

E.A. Savin, S.V. Matsievskiy, N.P. Sobenin, I.D. Sokolov
MEPhI, Moscow, Russia
A.A. Zavadtsev
Nano, Moscow, Russia

Compact electron linear accelerators for small energies are now found their place in the industrial market. Such accelerators are used for cancer treatment, cargo inspection, when one needs higher dose that X-ray source can produce, food and medicaments irradiation etc. Acceleration structures themselves are already developed very well, so the most important issue now ' is to make the whole installation with power supply, RF tracts, cooling system ' as smaller as possible to provide the structure mobility. In this article we present the development how to combine a power supply (usually it is a klystron, IOT, magnetron or solid state amplifier) with the accelerating cell itself, that can decrease installation size at least twice. No RF tracts needed, no reflected power will occur, so no circulator needed. Different power input combinations have been studied, but the smallest and the most efficient one has been manufactured for cold tests at S-band frequency range. In this structure it is very easy to vary accelerating voltage simply changing the generator beam current or the generator beam accelerating voltage.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW024

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW025

First Beam Test of the High Brightness Photo-injector at NSRRC

laser, gun, linac, cathode

1800

A.P. Lee, M.C. Chou, N.Y. Huang, J.-Y. Hwang, W.K. Lau, C.C. Liang, M.T. Tsou
NSRRC, Hsinchu, Taiwan
P. Wang
NTHU, Hsinchu, Taiwan

A High brightness injector at NSRRC is built for a VUV/THz free electron laser (FEL) facility and light source R&D. This injector with a photocathode rf gun with a solenoid for emittance compensation, a UV laser system, a 5.2 m S-band linac as well as various beam diagnostic tools has been installed in the linac test laboratory. The main goal is to produce beams with emittance smaller than 1 mm-mrad at energy of ~100 MeV. The other goal is to compress bunches to ~100 fs with charge of 100 pc and energy of ~30 MeV. In this contribution, an overview of the commissioning results of the photocathode rf gun and the laser system will be given. The first beam observation downstream the lianc will be presented in this paper.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW025

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW026

Optimization of Electron Beam Properties for Generation of Coherent THz Undulator Radiation at PBP-CMU Linac Laboratory

radiation, undulator, linac, emittance

1803

N. Chaisueb, S. Rimjaem, J. Saisut, C. Thongbai
Chiang Mai University, Chiang Mai, Thailand

Funding: This work has been supported by the CMU Junior Research Fellowship Program, the Department of Physics and Material Science, Chiang Mai University, and the Science Achievement Scholarship of Thailand.
Relativistic femtosecond electron bunches produced from the linear accelerator at the Plasma and Beam (PBP) Physics Research Facility are currently used to generate THz radiation via transition radiation. An upgrade to increase the intensity of the THz radiation by using a coherent undulator radiation method is conducted. Optimizations, measurements and analysis of the electron beam properties, which include current, energy and energy spread as well as electron bunch length, are performed to investigate the capability of electron beam production from the current accelerator system. This is also to estimate the possibility to produce the coherent undulator radiation of the PBP-CMU linac. Expected characteristics of the coherent undulator radiation are studied and reported in this contribution.
The authors would like to acknowledge the financial support to participate this conference by the Department of Physics and Material Science and the Graduate School, Chiang Mai University.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW026

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW039

Simulation Study of the Beam Halo Formation for Beam Loss Estimation and Mitigation at KEK Compact ERL

simulation, cavity, operation, gun

1843

O. Tanaka, T. Miyajima, N. Nakamura, T. Obina, M. Shimada, R. Takai
KEK, Ibaraki, Japan

Funding: Work supported by the "Grant-in-Aid for Creative Scientific Research" of JSPS (KAKENHI 15K04747)
At KEK Compact ERL (cERL) we are aiming to produce high-current and low-emittance electron beams (up to 10 mA) without significant beam loss. We believe that beam halo makes a significant impact into the beam loss. Therefore, we are performing beam loss simulations to meet the results of the beam loss measurements*. In particular, a simulation of the bunch tail originated from the electron gun was performed to understand the mechanisms of the beam halo formation. Since some measured beam profiles demonstrated unexpected halo particles, several factors such as misalignment of beam line elements and kicks from the steering coils were added into the simulation. Simulation study results are compared with the related beam loss and halo measurements here.
* Sakanaka et al., these proceedings

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW039

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW040

UH-FLUX: Compact, Energy Efficient Superconducting Asymmetric Energy Recovery LINAC for Ultra-high Fluxes of X-ray and THz Radiation

cavity, HOM, radiation, coupling

1847

I.V. Konoplev, A. Seryi
JAI, Oxford, United Kingdom
R. Ainsworth
Fermilab, Batavia, Illinois, USA
G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom

Funding: This work was supported (in part) by The Leverhulme Trust through the International Network Grant IN-2015-012.
The conventional ERLs have limited peak beam current because increasing the beam charge and repetition rate leads to appearance of the beam break-up instabilities. At this stage the highest current, from the SRF ERL, is around 300 mA. A single turn (the beam will be transported through the accelerating section, interaction point and deceleration section of the AERL only once) Asymmetric Energy Recovery LINAC (AERL) is proposed. The RF cells in different sections of the cavity are tuned in such a way that only operating mode is uniform inside all of the cells. The AERL will drive the electron beams with typical energies of 10 - 30 MeV and peak currents above 1 A, enabling the generation of high flux UV/X-rays and high power coherent THz radiation. We aim to build a copper prototype of the RF cavity for a compact AERL to study its EM properties. The final goal is to build AERL based on the superconducting RF cavity. Preliminary design for AERL's cavity has been developed and will be presented. The results of numerical and analytical models and the next steps toward the AERL operation will also be discussed.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW040

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW041

Optimization Studies for the Beam Dynamic in the RF Linac of the ELI-NP Gamma Beam System

laser, linac, photon, emittance

1850

C. Vaccarezza, D. Alesini, M. Bellaveglia, M.E. Biagini, G. Di Pirro, A. Gallo, A. Ghigo, S. Guiducci, A. Vannozzi, A. Variola
INFN/LNF, Frascati (Roma), Italy
A. Bacci, I. Drebot, D.T. Palmer, A.R. Rossi, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano, Italy
G. Campogiani
Rome University La Sapienza, Roma, Italy
A. Giribono, A. Mostacci, L. Palumbo
University of Rome La Sapienza, Rome, Italy
V. Petrillo
Universita' degli Studi di Milano & INFN, Milano, Italy
L. Sabbatini
Consorzio Laboratorio Nicola Cabibbo, Frascati, Italy

The ELI-NP GBS is an high spectral density and monochromatic gamma ray source based upon the inverse Compton scattering effect now under construction in Magurele. Its relevant specifications are brilliance higher than 10²¹, 0.5% monochromaticity and a 0.2-19.5 MeV energy tunability. Strong requirements are set for the electron beam dynamic: the control of both the transverse normalized emittance and the energy spread to optimize the spectral density and guarantee the mono chromaticity of the emitted radiation. On this basis the RF Linac optimization has been performed for the designed energy range; a sensitivity analysis of the machine to possible jitters, errors and so on has been also performed, the simulations results hare here presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW041

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW042

Expected Gamma Spectra at ELI-NP-GBS

photon, laser, polarization, collimation

1854

I. Drebot, C. Curatolo
Universita' degli Studi di Milano e INFN, Milano, Italy
A. Bacci, A.R. Rossi, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano, Italy
A. Giribono
University of Rome "La Sapienza", Rome, Italy
V. Petrillo
Universita' degli Studi di Milano & INFN, Milano, Italy
C. Vaccarezza, A. Variola
INFN/LNF, Frascati (Roma), Italy

The ELI-NP-GBS is an advanced source of up to 20 MeV Gamma Rays based on Compton back-scattering. We present the investigation of the production of the ELI-NP gamma photon beam generated by Compton back-scattering between the electron bunch accelerated in the linac and the laser pulse. At the interaction point (IP), the Compton backscattering properties, as spectral flux, brilliance and polarization are evaluated by the Klein-Nishina cross section. The gamma beam produced has energy ranging from 0.2 to 19.5 MeV and bandwidth of 0.5%. In order to define the optimal layout and evaluate the performances of the collimation and detection systems, a detailed Monte Carlo simulation activity has been carried out taking into account possible jitters and errors.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW042

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW043

Electron Beam Dynamics Studies for ELI-NP GBS Linac

linac, operation, beam-loading, photon

1857

A. Giribono, F. Cardelli, L. Palumbo, L. Piersanti
University of Rome La Sapienza, Rome, Italy
D. Alesini, A. Gallo, C. Vaccarezza, A. Vannozzi
INFN/LNF, Frascati (Roma), Italy
A. Bacci, C. Curatolo, I. Drebot, V. Petrillo, A.R. Rossi, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano, Italy
G. Campogiani
Rome University La Sapienza, Roma, Italy
F. Cardelli, L. Piersanti
INFN-Roma1, Rome, Italy
L. Palumbo
INFN-Roma, Roma, Italy

The ELI-NP Gamma Beam System is an advanced gamma ray source based on the Compton back-scattering effect with unprecedented specifications of brilliance ( >10²¹), monochromaticity (0.5%) and energy tunability (0.2 - 19.5 MeV), presently under construction in Magurele-Bucharest (RO). Here the head-on collision is foreseen between an intense high power laser beam and a high brightness high quality electron beam with a maximum kinetic energy of 740 MeV. The electron beam dynamics analysis and control for the ELI-NP GBS Linac in the single and multi bunch mode have been investigated and are here illustrated.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW043

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW044

Experimental Investigation of THz Smith-Purcell Radiation From Composite Corrugated Capillary

radiation, simulation, detector, vacuum

1861

K. Lekomtsev, A. Aryshev, M. Shevelev, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
A. Ponomarenko, A.A. Tishchenko
MEPhI, Moscow, Russia

Funding: This work was supported by Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan.
Terahertz part of electromagnetic spectrum has a variety of potential applications ranging from fundamental to security applications. Further advances in development of a linac based, tunable, and narrow band coherent source of THz radiation are very important. Mechanisms of Cherenkov radiation and Smith-Purcell radiation (SPR) [*] may be used for generation of THz radiation via coherent emission [**, ***]. In this report we will present experimental investigations of the SPR generated from the corrugated capillary with a reflector, using the femtosecond multi-bunch electron beam of LUCX accelerator at KEK, Japan [****]. LUCX is capable to generate a train of 4 bunches each with 200 femtosecond (60 micrometer) duration and 200 micrometer transverse size. We will discuss the composite design of the capillary, measurements of the SPR angular distributions and the comparison of these measurements with PIC simulations. In addition, we will discuss SPR spectral characteristics; bunch energy modulation, introduced by the corrugated capillary; and the way in which the bunch spacing changes the spectrum and angular distributions of SPR.
*K.Lekomtsev et al., NIMB 355 (2015) 164
**A. M. Cook et al., PRL 103, (2009) 095003.
***S. E. Korbly et al., PRL 94, (2005) 054803.
****A. Aryshev, arXiv:1507.03302 [physics.acc-ph]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW044

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW045

Pre-bunched Electron Beam Emittance Simulation and Measurement

simulation, emittance, gun, radiation

1864

Yu.D. Kliuchevskaia, S.M. Polozov
MEPhI, Moscow, Russia
A. Aryshev, M. Shevelev, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan

LUCX facility at KEK is used as the high brightness pre-bunched electron beam source for radiation experiments. Emittance measurement and optimization is one of the important research activities for newly developed operation mode of the facility. Characterization of the pre-bunched beam (THz sequence of a hundred femtosecond bunches) properties opens a possibility to establish detailed simulation of the THz FEL radiation yield and continuously improve pre-bunched beam dynamics insight. Emittance has been measured by the Q-scan method. The measurement results and possible ways of emittance optimization are discussed. The measurement results are compared with beam dynamics simulation done by self-consistent BEAMDULAC-BL code.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW045

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW046

Development and Upgrade Plan of an X-ray Source Based on Laser Compton Scattering in Laser Undulator Compact X-ray Source(LUCX)

laser, detector, cavity, photon

1867

M.K. Fukuda, S. Araki, Y. Honda, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
M. Kageyama, M. Kuribayashi
Rigaku Corporation, XG & Core Technology, Tokyo, Japan
A. Momose, M.P. Olbinado, Y. Wu
Tohoku University, Institute of Multidisciplinary Research for Advanced Materials, Sendai, Japan
K. Sakaue
Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan
M. Washio
RISE, Tokyo, Japan

Funding: This work was supported by Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan.
We have been developing a compact X-ray source based on Laser Compton scattering(LCS) at Laser Undulator Compact X-ray source(LUCX) accelerator in KEK. Our aim is to obtain a clear X-ray image in a shorter period of times and the target number of X-ray is 1.7x10⁷ photons/pulse with 10% bandwidth. In the accelerator, an electron beam with the energy of 18-24 MeV is generated by an S-band normal conducting accelerator. The beam is collided with a laser pulse stacked in a 4-mirror planar optical cavity and then 6-10 keV X-rays are generated by LCS. Presently, the generation of X-rays with the number of 3x10⁶ photons/pulse at the collision point has been achieved. X-ray imaging test such as refraction contrast images and phase contrast imaging with Talbot interferometer has also started. To increase the intensity of X-rays, we are continuing the tuning of the electron beam and the optical cavity because the exposure time of X-ray imaging is too long now. We are also planning to increase the beam energy by appending the accelerating tube. In this conference, the recent results and upgrade plan in LUCX will be reported.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW046

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW047

Generation of a Coherent Cherenkov Radiation by using Electron Bunch Tilting

radiation, target, gun, experiment

1870

K. Sakaue
Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan
R. Kuroda, Y. Taira
AIST, Tsukuba, Ibaraki, Japan
M. Nishida, M. Washio
Waseda University, Tokyo, Japan
J. Urakawa
KEK, Ibaraki, Japan

We have been developing a compact accelerator based a laser photocathode rf electron gun at Waseda University. Low emittance and short bunched electron beam can be generated from the gun. Also, the rf transverse deflecting cavity was developed for the bunch length measurement. We performed an experiment for generating a coherent Cherenkov radiation using bunch tilting. The rf transverse deflector can give a tilt for the electron bunch, and the tilt angle was set to the Cherenkov radiating angle which determined by the target refractive index. We successfully demonstrated a coherent Cherenkov radiation and the characterization of the radiation. The principle of coherent Cherenkov radiation generation, the experimental results and future prospective will be presented at the conference.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW047

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW049

Expected Results From Channeling Radiation Experiments at Fast

photon, detector, background, emittance

1873

T. Sen, D.R. Broemmelsiek, D.R. Edstrom
Fermilab, Batavia, Illinois, USA
J. Hyun
Sokendai, Ibaraki, Japan
D. Mihalcea, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
W.D. Rush
KU, Lawrence, Kansas, USA

Funding: Fermilab is operated by Fermi Research Alliance LLC under DOE contract No. DE-AC02CH11359
The photoinjector at the new Fermilab FAST facility will accelerate electron beams to about 50 GeV. After initial beam commissioning, channeling radiation experiments to generate hard X-rays will be performed. In the initial stage, low bunch charge beams will be used to keep the photon count rate low and avoid pile up in the detector. We report here on the optics solutions, the expected channaling spectrum including background from bremmstrahlung and the use of a Compton scatterer for higher bunch charge operation.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW049

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW050

Parametric X-rays at FAST

brilliance, photon, detector, scattering

1877

T. Sen
Fermilab, Batavia, Illinois, USA

Funding: Fermilab is operated by Fermi Research Alliance LLC under DOE contract No. DE-AC02CH11359
We discuss the generation of parametric X-rays (PXR) in the photoinjector at the new FAST facility at Fermilab. Detailed calculations of the intensity spectrum, energy and angular widths and spectral brilliance with a diamond crystal are presented. We also report on expected results with PXR generated while the beam is channeling. The low emittance electron beam makes this facility a promising source for creating brilliant X-rays.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW050

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW051

Optimization of Electron Beam and Laser Pulse Alignment and Focusing at Interaction Point for a Compact FEL Based Inverse-Compton Scattering X-Ray Source

laser, photon, FEL, undulator

1881

P. Niknejadi, J. Madey
University of Hawaii, Honolulu,, USA

Funding: This work was funded under the Department of Homeland Security Grant No. 2010-DN-077-ARI045.
In July 2015, the first beam of 10 keV X-rays from our FEL based inverse-Compton scattering X-ray source was detected.* In this setup, 3 micron laser pulses at 2.856 GHz repetition rate from a free electron laser are collided head-on with 40 MeV electron bunches driving the laser. To attain our objective the ebeam was required to have 1) a tight focus at the X-ray interaction point, 2) vertical and horizontal envelopes matched to the downstream undulator, 3) minimized transverse dimensions for low ionizing radiation. Optimization of these quantities required information on the evolution of the beam profiles between the beam spot images on the available insertable screens, leading to the need for a simulator to accurately trace the beam profiles through the system. A simulator was developed and used to optimize the system Twiss parameters by comparing the effectiveness of the beam profiles computed by fitting the profiles to the observed beam spot images along the beamline for different cathode positions. This method proved to be considerably more flexible and effective than the more traditional quadrupole scan technique. Summery of the designed system and results are provided.
* John M. J. Madey, ARI final report, December 2015.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW051

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW052

LLNL Laser-Compton X-ray Characterization

laser, photon, simulation, background

1885

Y. Hwang, T. Tajima
UCI, Irvine, California, USA
G.G. Anderson, C.P.J. Barty, D.J. Gibson, R.A. Marsh
LLNL, Livermore, California, USA

Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344
Laser-Compton X-rays have been produced at LLNL, and results agree very well with modeling predictions. An X-ray CCD camera and image plates were calibrated and used to characterize the 30 keV X-ray beam. A resolution test pattern was imaged to measure the source size. K-edge absorption images using thin foils confirm the narrow bandwidth of the source and offer electron beam diagnostics.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW052

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW053

Measurement of Terahertz Generation in a Metallic, Corrugated Beam Pipe

radiation, experiment, dipole, laser

1889

K.L.F. Bane
SLAC, Menlo Park, California, USA
S.P. Antipov
ANL, Argonne, Illinois, USA
M.G. Fedurin, K. Kusche, C. Swinson
BNL, Upton, Long Island, New York, USA
D. Xiang
Shanghai Jiao Tong University, Shanghai, People's Republic of China

Funding: Work supported by the Department of Energy, Office of Science, Office of Basic Energy Science, under Contract No. DE-AC02-76SF00515
A method for producing narrow-band THz radiation proposes passing an ultra-relativistic beam through a metallic pipe with small periodic corrugations*. We present results of a measurement of such an arrangement at BNL's Advanced Test Facility (ATF). Our pipe was copper and was 5 cm long; the aperture was cylindrically symmetric, with a 1 mm (radius) bore and a corrugation depth (peak-to-peak) of 60 um. In the experiment we measured both the effect on the beam of the structure wakefield and the spectral properties of the radiation excited by the beam. We began by injecting a relatively long beam–-compared to the wavelength of the radiation–-to excite the structure, and then used a downstream spectrometer to infer the radiation wavelength. This was followed by injecting a shorter bunch, and then using an interferometer (also downstream of the corrugated pipe) to measure the spectrum of the induced THz radiation. Our experimental set-up was simple and not optimized for the efficient collection of the radiation by e.g. the use of tapered horns. As such it can be considered a proof-of-principle experiment.
* K. Bane and G. Stupakov, NIM A677 (2012) 67-73.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW053

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW054

Characterization of a Sub-THz Radiation Source Based on a 3 MeV Electron Beam and Future Plans

radiation, experiment, quadrupole, laser

1892

A.V. Smirnov, R.B. Agustsson, T.J. Campese, Y.C. Chen, J.J. Hartzell, B.T. Jacobson, A.Y. Murokh, M. Ruelas
RadiaBeam, Santa Monica, California, USA
W. Berg, J.C. Dooling, L. Erwin, R.R. Lindberg, S.J. Pasky, N. Sereno, Y.-E. Sun, A. Zholents
ANL, Argonne, Ilinois, USA
Y. Kim
KAERI, Jeongeup-si, Republic of Korea

Funding: This work was supported by the U.S. Department of Energy (award No. DE-SC-FOA-0007702)
Design features and some past experimental results are presented for a sub-THz wave source employing the Advanced Photon Source's RF thermionic electron gun. The setup includes a compact alpha-magnet, four quadrupoles, a novel radiator, a THz transport line, and THz diagnostics. The radiator is composed of a dielectric-free, planar, over-sized structure with gratings. The gratings are integrated into a combined horn antenna and ~90° permanent bending magnet. The magnetic lattice enables operation in different modes, including conversion to a flat beam for efficient interaction with the radiating structure. The experiment described demonstrated the generation of narrow bandwidth THz radiation from a compact, laser and undulator-free, table-top system. This concept could be scaled to create a THz-sub-THz source capable of operating in long-pulse, multi-bunch, and CW modes. Additionally, the system can be used to remove unwanted time-dependent energy variations in longitudinally compressed electron bunches or for various time-dependent beam diagnostics. Plans for future experiments and upgrades are also discussed.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW054

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOY007

Development of a Compact X-Band Electron Linac for Production of Mo-99/Tc-99m

linac, beam-loading, simulation, klystron

1917

J. Jang
The University of Tokyo, Tokyo, Japan
M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
M. Yamamoto
Accuthera Inc., Kawasaki, Kanagawa, Japan

In response to the need of alternatives to the exhausted research reactors supplying Mo-99/Tc-99m, we are developing a compact X-band electron linear accelerator (linac). As an initial step, beam dynamics simulations were performed and electron beams of 35 MeV and 9.1 kW were obtained. We expect that sixteen linacs having these beam parameters can cover the demand of Tc-99m radiopharmaceuticals in Japan. On the other hand, we found that the combination of X-band RF and high beam power can give rise to instability of beam loading. We will therefore adjust and optimize the beam power while keeping Mo-99 production efficiency as high as possible.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOY007

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOY008

Design of a Radiotherapy Machine using the 6 MeV C-Band Standing-Wave Accelerator

linac, radiation, vacuum, controls

1921

H. Lim, D.H. Jeong, M.W. Lee, M.J. Lee, S.W. Shin, J. Yi
Dongnam Institute of Radiological and Medical Sciences, Busan, Republic of Korea

The majority of the radiotherapy are performed with linacs producing a uniformly intense electron-beam or X-ray beam of different energies. The linacs have the strong attraction of compactness, efficiency, reliability, moderate cost, and well-known technology. We developed and constructed the 6 MeV C-band linac which consists of a thermionic electron gun, a standing-wave accelerating column with the length of 450 mm, a 2.5 MW magnetron, a beam transport system, a beam collimation and monitoring system, and auxiliary systems of vacuum system, water cooling system etc. For the medical application, the gantry system is required to be rotated around the patient and to deliver the beam to the tumor from the linac. We design the gantry mounting our developed C-band linac isocentrically. In addition, the beam bending system and beam collimation are discussed to optimize the gantry space and to improve the beam performance. In this paper, we describe the designed radiotherapy machine including the gantry, a treatment couch and a control console, and present the study results.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOY008

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOY010

6/9 MeV S-band Standing Wave Accelerating Structure for Container X-ray Inspection System at RTX

cavity, linac, gun, radiation

1924

P. Buaphad, H.D. Park, S. Song, S.Y. Yoo
RTX, Daejeon, Republic of Korea
H.K. Cha, S.S. Cha, J.H. Ha, Y. Kim, B.C. Lee
KAERI, Daejon, Republic of Korea

Recently, there is a need of X-ray inspection system around the world to combat terrorism, drug and weapons smuggling, illegal immigration, and trade fraud. A compact standing wave (SW) linear accelerator (linac) for container X-ray inspection system has been produced at Radiation Technology eXcellence (RTX) to meet this growing need. The RF accelerating structure uses standing wave side-coupled structure fed by a 5 MW e2v magnetron with frequency of 2856 MHz. The electrons are accelerated from DC gun with energy of 25 keV to the final energy of 6 or 9 MeV at the X-ray target and generate X-ray with the dose rate of 8 Gy/min at 1 m after X-ray target. In this paper, we describe the design and optimization of side-coupled RF structure operating at π/2 mode. The beam dynamic of particle along the RF structure is also included in this paper by using ASTRA code.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOY010

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOY015

Design of Electron Gun and S-Band Structure for Medical Electron Linear Accelerator

gun, cavity, cathode, linac

1930

N. Juntong, R. Chimchang
SLRI, Nakhon Ratchasima, Thailand
S. Rimjaem, C. Saisa-ard
Chiang Mai University, Chiang Mai, Thailand

Linear accelerator technology has been widely utilized for cancer treatment in hospital. This radiotherapy utilizes an accelerated electron beam to create the x-ray beam. The idea to fabricate the prototype of medical electron linac with low cost for domestic use in Thailand was proposed and the budget has been granted. In the first phase, the electron beam energy of the machine will be 6 MeV or equivalent to x-ray energy of 6 MV. The electron gun is a diode type for the simple and low cost fabrication. The design and simulation study of diode gun will be presented together with an analysis of an electron beam in this gun. The S-Band 6 MeV side-coupled RF cavity has been designed to be the accelerating structure of the machine. The electromagnetic fields of the structure have been studied. The electron behaviour when they traverse this cavity will be studied using a particle tracking code. Progression of the project is also presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOY015

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOY016

The Optimized X-ray Target of Electron Linear Accelerator for Radiotherapy

target, simulation, linac, detector

1933

N. Juntong, K. Pharaphan
SLRI, Nakhon Ratchasima, Thailand

The x-ray target in medical electron linear accelerator is an important part in the production of x-ray photon beam. X-ray dose rate is depended on materials and thickness of the target. For the low cost 6 MeV prototype of medical linac in Thailand, this study gives the optimized x-ray target in which the dose rate can be maximized. MCNP simulations were performed during an optimization for a high x-ray dose rate at 1 meter away from the target. Progression of the project is also presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOY016

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOY024

Wave Particle Cherenkov Interactions Mediated via Novel Materials

simulation, acceleration, operation, scattering

1960

A. Hopper
IIAA, Huddersfield, United Kingdom
R. Seviour
University of Huddersfield, Huddersfield, United Kingdom

Currently there is an increasing interest in dielectric wall accelerators. These work by slowing the speed of an EM wave to match the velocity of a particle beam, allowing wave-beam interactions, accelerating the beam. However conventional dielectric materials have limited interaction regions, so wave-beam energy transfer is minimal. In this paper we consider Artificial Materials (AMs), as slow wave structures, in the presence of charged particle beams to engineer Inverse-Cherenkov acceleration. AMs are periodic constructs whose properties depend on their subwavelength geometry rather than their material composition, and can be engineered to give an arbitrary dispersion relation. We show that Metamaterials, one example of an AM, can mediate an Inverse-Cherenkov interaction, but break down in high power environments due to high absorption. We consider AMs with low constitutive parameters and show they can exhibit low absorption whilst maintaining the ability to have a user defined dispersion relation, and mediate a wavebeam interaction leading to Inverse-Cherenkov acceleration.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOY024

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOY027

Beam Dynamics Studies into Grating-based Dielectric Laser-driven Accelerators

laser, accelerating-gradient, emittance, simulation

1970

Y. Wei, S.P. Jamison, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
K. Hanahoe, Y. M. Li, G.X. Xia
UMAN, Manchester, United Kingdom
S.P. Jamison
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
J.D.A. Smith
TXUK, Warrington, United Kingdom
Y. Wei, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: Work supported by the EU under grant agreement 289191 and the STFC under the Cockcroft Institute core grant ST/G008248/1.
Dielectric laser-driven accelerators (DLAs) based on gratings confine an electromagnetic field induced by a drive laser into a narrow vacuum channel where electrons travel and are accelerated. This can provide an alternative acceleration technology compared to conventional rf cavity accelerators. Due to the achievable high acceleration gradient of up to several GV/m this could pave the way for future ultra-short and low costμaccelerators. This contribution presents detailed beam dynamics simulations for multi-period double grating structures. Using the computer code VSim and realistic beam distributions, the achievable acceleration gradient and final beam quality in terms of emittance and energy spread are discussed. The results are then used for an overall optimization of the accelerating structure.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOY027

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOY032

Design and Simulation of a Thermionic Electron Gun for a 1 MeV Parallel Feed Cockcroft-Walton Industrial Accelerator

gun, cathode, simulation, space-charge

1976

M. Nazari, F. Abbasi
Shahid Beheshti University, Tehran, Iran
F. Ghasemi
NSTRI, Tehran, Iran
M. Jafarzadeh
ILSF, Tehran, Iran

Electron accelerators are made of different parts and one of the main part of every electron accelerator is its electron gun. In this article a diode electron gun is designed and simulated for a 1MeV parallel feed Cockcroft-Walton accelerator for industrial applications. The pierce configuration is selected for focusing electrode. Simulations are carried out using CST Particle Studio. The gun is thermionic with indirect heating of spherical dispenser cathode that is made from porous tungsten which is impregnated with barium compounds. The gun maximum achievable current is 200 mA at 10 kV and required current in our accelerator is about 100 mA.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOY032

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOY033

Design, Simulation and Comparison of Electrostatic Accelerating Tubes for a 1MeV Parallel Feed Cockcroft-Walton Industrial Accelerator

gun, simulation, industrial-accelerators, vacuum

1979

M. Nazari, F. Abbasi
Shahid Beheshti University, Tehran, Iran
F. Ghasemi
NSTRI, Tehran, Iran
M. Jafarzadeh
ILSF, Tehran, Iran

In this article accelerating tubes whit different geometries and different constructions are designed and simulated for a 1 MeV parallel feed Cockcroft-Walton electrostatic industrial accelerator. Simulations are carried out using CST Particle Studio. The accelerating tubes with different focusing electrode and accelerating electrode geometries are designed and simulated and compared with each other. Finally whit respect to the comparisons best geometry is selected. In this tube a 1 MV DC voltage is applied at several stages during the accelerating electrodes. Maximum electron beam current in the tube is 200 mA. In this application accelerating electrodes and focusing electrodes are made of stainless steel and insulators between electrodes are made of Borosilicate glass.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOY033

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOY039

Studies on Electron Linear Accelerator System for Polymer Research

linac, coupling, radiation, plasma

1985

E. Kongmon
IST, Chiang Mai, Thailand
N. Kangrang
Chiang Mai University, PBP Research Facility, Chiang Mai, Thailand
S. Rimjaem, J. Saisut, C. Thongbai
Chiang Mai University, Chiang Mai, Thailand
P. Wichaisirimongkol
Chiang Mai University, Science and Technology Research Institute, Chiang Mai, Thailand

This research focuses on modification of an elec-tron linear accelerator system for irradiation of natural rubber latex and polymeric materials at the Plasma and Beam Physics Research Facility, Chiang Mai Universi-ty, Thailand. This is in order to study the change of material properties due to electron beam irradiation. The main accelerator system consists of a DC thermi-onic electron gun and a short standing-wave linac. This system will be able to produce electron beams with variable energy in the range of 0.5 to 4 MeV. The linac macro pulse frequency is adjustable within the range of 20 to 1000 Hz. The macro pulse duration is 4 μs. The electron pulse current can be varied from 10 to 100 mA. This lead to the electron dose of about 0.44 to 4.4 Gy-m2/min. In this paper, overview of the accelera-tor and the irradiation system is presented. Results of low-level RF measurements of the accelerating struc-ture are also reported and discussed.
This work has been supported by the CMU Junior Research Fellowship Program, the Department of Physics and Material Science, Faculty of science, Chiang Mai University.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOY039

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOY040

Advancements in Single-shot Electron Diffraction on VELA at Daresbury Laboratory

laser, cavity, gun, cathode

1988

J.W. McKenzie, S.L. Mathisen, M.D. Roper, M. Surman
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
D.M.P. Holland
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
J.G. Underwood
UCL, London, United Kingdom

Electron diffraction on VELA at Daresbury Laboratory was first demonstrated in 2014. Since then, we have studied the machine parameter optimisation for single-shot diffraction patterns from single-crystal gold and silicon samples at bunch charges down to 60 fC. We present bunch length measurements for electron diffraction setups determined with a transverse deflecting cavity. We also discuss the current limitations of VELA for electron diffraction and the improvements to be made.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOY040

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOY041

A Metal-Dielectric Micro-Linac for Radiography Source Replacement

focusing, linac, vacuum, coupling

1992

A.V. Smirnov, S. Boucher, S.V. Kutsaev
RadiaBeam Systems, Santa Monica, California, USA
R.B. Agustsson, R.D.B. Berry, J.J. Hartzell, J. McNevin, A.Y. Murokh
RadiaBeam, Santa Monica, California, USA
G. Leyh
LOD, Brisbane, USA
E.A. Savin
MEPhI, Moscow, Russia

Funding: * US Department of Energy Contract # DE-SC0011370
To improve public security and prevent the diversion of radioactive material for Radiation Dispersion Devices, RadiaBeam is developing an inexpensive, portable, easy-to-manufacture linac structure to allow effective capture of a ~13 keV electron beam injected from a conventional electron gun and acceleration to a final energy of ~ 1 MeV. The bremsstrahlung X-rays produced by the electron beam on a high-Z converter at the end of the linac will match the penetration and dose rate of a typical ~100 Ci or more Ir-192 source. The tubular Disk-and-Ring structure under development consists of metal and dielectric elements that reduce or even eliminate multi-cell, multi-step brazing. This may allow significant simplification of the fabrication process to enable inexpensive mass-production required for replacement of the ~55,000 radionuclide sources in the US

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOY041

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOY050

Microtron-based Intense Neutron Source

microtron, cavity, neutron, cathode

2014

G.M. Kazakevich, R.J. Abrams, R.P. Johnson, S.A. Kahn
Muons, Inc, Illinois, USA
M.A.C. Cummings
Northern Illinois University, DeKalb, Illinois, USA

Funding: Funded by DOE SBIR grant DE-SC0013795
An L-Band 7.7-9.8 MeV CW relatively inexpensive microtron with a warm accelerating cavity for multi-purpose applications in nuclear medicine and radiation industry is proposed. The microtron with a photo-neutron converter is intended to serve as an intense source of photo-neutrons with yield up to 4·10¹² n/s for nuclear medicine or/and producing of short lived isotopes, as a source of gamma-radiation with dose rates up to 130 kR/min·m with a heavy bremsstrahlung target, and as a source of the electron beam with total energy of 9.8 MeV at the average current up to 4.4 mA for various radiation treatments.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOY050

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEZA01

RHIC Performance with Stochastic Cooling for Ions and Head-on Beam-beam Compensation for Protons

luminosity, operation, proton, ion

2055

W. Fischer, J.G. Alessi, Z. Altinbas, E.C. Aschenauer, G. Atoian, E.N. Beebe, S. Binello, I. Blackler, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, R. Connolly, M.R. Costanzo, T. D'Ottavio, K.A. Drees, A.V. Fedotov, C.J. Gardner, D.M. Gassner, X. Gu, C.E. Harper, M. Harvey, T. Hayes, J. Hock, H. Huang, R.L. Hulsart, J.P. Jamilkowski, T. Kanesue, N.A. Kling, J.S. Laster, C. Liu, Y. Luo, D. Maffei, Y. Makdisi, M. Mapes, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, T.A. Miller, M.G. Minty, C. Montag, J. Morris, G. Narayan, C. Naylor, S. Nemesure, M. Okamura, S. Perez, A.I. Pikin, P.H. Pile, A. Poblaguev, V. Ptitsyn, V.H. Ranjbar, D. Raparia, G. Robert-Demolaize, T. Roser, J. Sandberg, W.B. Schmidke, V. Schoefer, F. Severino, T.C. Shrey, K.S. Smith, D. Steski, S. Tepikian, R. Than, P. Thieberger, J.E. Tuozzolo, B. Van Kuik, G. Wang, K. Yip, A. Zaltsman, A. Zelenski, K. Zeno, W. Zhang
BNL, Upton, Long Island, New York, USA
M. Bai, Y. Dutheil
FZJ, Jülich, Germany
S.M. White
ESRF, Grenoble, France

Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH10886 with the U.S. Department of Energy.
The Relativistic Heavy Ion Collider (RHIC) has two main operating modes with heavy ions and polarized protons respectively. In addition to a continuous increase in the bunch intensity in all modes, two major new systems were completed recently mitigating the main luminosity limit and leading to significant performance improvements. For heavy ion operation stochastic cooling mitigates the effects of intrabeam scattering, and for polarized proton operation head-on beam-beam compensation mitigated the beam-beam effect. We present the performance increases with these upgrades for heavy ions and polarized protons, as well as an overview of all operating modes past and planned.

Slides WEZA01 [12.687 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEZA01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOCA03

Simulating Proton Synchrotron Radiation in the Arcs of the LHC, HL-LHC and FCC-hh

photon, optics, simulation, radiation

2073

G. Guillermo Cantón, F. Zimmermann
CERN, Geneva, Switzerland
D. Sagan
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

At high proton-beam energies, beam-induced synchrotron radiation is an important source of heating, of beam-related vacuum pressure increase, and of primary photoelectrons, which can give rise to an electron cloud. We use the Synrad3D code developed at Cornell to simulate the photon distributions in the arcs of the LHC, HL-LHC, and FCC-hh. Specifically, for the LHC we study the effect of the "sawtooth" chamber, for the HL-LHC the consequences of the ATS optics with large beta beating in the arcs, and for the FCC-hh the effect of a novel beam-screen design, with a long slit surrounded by a "folded" ante-chamber.

Slides WEOCA03 [0.329 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEOCA03

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOAB01

Advanced Acceleration Mechanisms for Laser Driven Ions by PW-lasers

laser, ion, acceleration, target

2082

S.S. Bulanov, E. Esarey, Q. Ji, W. Leemans, T. Schenkel, S. Steinke
LBNL, Berkeley, California, USA

Funding: This work was supported by LDRD funding from Berkeley Laboratory, provided by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
With the fast development of laser technology the energy of laser accelerated proton beams rose up to almost 100 MeV. The PW-class laser facilities that are being built right now or are already in operation, such as the Berkeley Lab Laser Accelerator (BELLA) Center, will offer peak intensities approaching 10²² W/cm². This will allow the development of a new generation laser ion accelerators for numerous applications. The integral part of this task is the investigation of the advanced acceleration mechanisms for laser driven ion beams that would allow for a high degree of control over the angular and energy distributions of ion beams, as well as the increase of the maximum ion energy. We will present recent theoretical and simulation results on three advanced acceleration mechanisms: (i) Directed Coulomb Explosion*, (ii) Radiation Pressure Acceleration**, and (iii) Magnetic Vortex acceleration***.
Reference:
* S. S. Bulanov et al, Phys. Rev. E 78, 026412 (2008).
** S. S. Bulanov et al, Phys. Rev. Lett. 114, 105003 (2015).
*** S. S. Bulanov et al, Phys. Rev. STAB 18, 061302 (2015).

Slides WEOAB01 [39.942 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEOAB01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOAB02

Record Performance of SRF Gun with CsK2Sb Photocathode

cathode, gun, laser, cavity

2085

I. Pinayev, Z. Altinbas, S.A. Belomestnykh, I. Ben-Zvi, K.A. Brown, J.C. Brutus, A.J. Curcio, A. Di Lieto, C. Folz, D.M. Gassner, M. Harvey, T. Hayes, R.L. Hulsart, J.P. Jamilkowski, Y.C. Jing, D. Kayran, R. Kellermann, R.F. Lambiase, V. Litvinenko, G.J. Mahler, M. Mapes, W. Meng, K. Mernick, R.J. Michnoff, T.A. Miller, M.G. Minty, G. Narayan, P. Orfin, D. Phillips, T. Rao, J. Reich, T. Roser, B. Sheehy, J. Skaritka, L. Smart, K.S. Smith, L. Snydstrup, V. Soria, Z. Sorrell, R. Than, C. Theisen, J.E. Tuozzolo, E. Wang, G. Wang, B. P. Xiao, T. Xin, W. Xu, A. Zaltsman, Z. Zhao
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
High-gradient CW photo-injectors operating at high ac-celerating gradients promise to revolutionize many sci-ences and applications. They can establish the basis for super-bright monochromatic X-ray and gamma-ray sources, high luminosity hadron colliders, nuclear- waste transmutation or a new generation of microchip produc-tion. In this paper we report on our operation of a super-conducting RF electron gun with a record-high accelerat-ing gradient at the CsK2Sb photocathode (i.e. ~ 20 MV/m) generating a record-high bunch charge (i.e., 2 nC). We briefly describe the system and then detail our experimental results.

Slides WEOAB02 [28.500 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEOAB02

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOAB03

Photoemission Properties of LaB6 and CeB6 Under Various Temperature and Incident Photon Energy Conditions

cathode, laser, photon, vacuum

2088

K. Morita, T. Katsurayama, T. Kii, K. Masuda, T. Murata, K. Nagasaki, T. Nogi, H. Ohgaki, S. Suphakul, K. Torgasin, H. Yamashita, H. Zen
Kyoto University, Kyoto, Japan

Recently, thermionic cathode materials such as LaB6, Ir5Ce and dispenser cathodes have been also used as photocathode since they have low work function, reasonably high quantum efficiency, and long lifetime*,**. However, the effect of cathode temperature and laser wavelength on quantum efficiency is known only for limited conditions. Although it is expected to be able to lengthen the required wavelength of photocathode drive laser by heating cathodes, laser with photon energy under the work function has not been tested. Revealing them enables us to design the cost minimum accelerators. In this research, photoemission properties of LaB6 and CeB6 with various excitation photon energies will be investigated under various temperatures of the materials. Those materials have similar work function, but CeB6 have one order of magnitude smaller Richardson constant than LaB6***. By comparing photoemission properties of these materials, impact of Richardson constant on the photoemission properties will be investigated.
* S. Thorin et al. Proc of FEL2009, 310
** D. Satoh et al. Proc of IPAC2014, 679
*** J.M. Lafferty, J. Appl. Phys. 22, (1951), 299

Slides WEOAB03 [0.996 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEOAB03

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEYB01

Diagnostic Systems of the PAL-XFEL

target, electronics, diagnostics, pick-up

2091

C. Kim, S.Y. Baek, H. J. Choi, J.H. Hong, H.-S. Kang, G. Kim, J.H. Kim, I.S. Ko, S.J. Lee, G. Mun, B.G. Oh, B.R. Park, D.C. Shin, H. Yang
PAL, Pohang, Kyungbuk, Republic of Korea

The Pohang Accelerator Laboratory (PAL) started an x-ray free electron laser project (PAL-XFEL) in 2011. The construction was finished at the end of 2015 and the commissioning is planned from the beginning of 2016. In the PAL-XFEL, an electron beam with 200 pC will be generated from a photocathode RF gun and will be accelerated to 10 GeV by using a linear accelerator. The electron beam will pass through undulator section to produce hard X-ray radiation. For the successful commissioning and beam operation, various kinds of instruments were prepared.

Slides WEYB01 [11.770 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEYB01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOBB02

Status of Wakefield Monitor Experiments at the CLIC Test Facility

detector, emittance, pick-up, experiment

2099

R.L. Lillestøl, E. Adli, J. Pfingstner
University of Oslo, Oslo, Norway
N. Aftab, S. Javeed
PINSTECH, Islamabad, Pakistan
R. Corsini, S. Döbert, W. Farabolini, A. Grudiev, W. Wuensch
CERN, Geneva, Switzerland

For the very low emittance beams in CLIC, it is vital to mitigate emittance growth which leads to reduced luminosity in the detectors. One factor that leads to emittance growth is transverse wakefields in the accelerating structures. In order to combat this the structures must be aligned with a precision of a few um. For achieving this tolerance, accelerating structures are equipped with wakefield monitors that measure higher-order dipole modes excited by the beam when offset from the structure axis. We report on such measurements, performed using prototype CLIC accelerating structures which are part of the module installed in the CLIC Test Facility 3 (CTF3) at CERN. Measurements with and without the drive beam that feeds rf power to the structures are compared. Improvements to the experimental setup are discussed, and finally remaining measurements that should be performed before the completion of the program are summarized.

Slides WEOBB02 [2.928 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEOBB02

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOBB03

A Non-destructive Profile Monitor Using a Gas Sheet

ion, proton, target, experiment

2102

N. Ogiwara, Y. Hikichi, J. Kamiya, M. Kinsho, Y. Namekawa
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
M. Fukuda, K. Hatanaka, T. Shima
RCNP, Osaka, Japan

We are developing a dense gas-sheet target to realize a non-destructive and fast-response beam profile monitor for 3 GeV rapid cycling synchrotron (RCS) in the J-PARC. This time, to demonstrate the function of the gas sheet for measuring the 2 dimensional profiles of the accelerated beams, the following experiments were carried out: 1) The gas sheet with a thickness of 1.5 mm and the density of 2×10^-4 Pa was generated by the combination of the deep slit and the thin slit. Here, the gas sheet was produced by the deep slit, and the shape of the sheet was improved by the thin slit. 2) For the electron beam of 30 keV with a diameter greater than 0.35 mm, the position and the two-dimensional profiles were well measured using the gas sheet. 3) Then the profiles of the 400 MeV proton beam with a current of 1×10-6 A was well measured, too.

Slides WEOBB03 [4.718 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEOBB03

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMB006

XFEL Couplers RF Conditioning at LAL

vacuum, pick-up, site, controls

2125

H. Guler, A. Gallas, W. Kaabi, D.J.M. Le Pinvidic, C. Magueur, M. Oublaid, A. Thiebault, A. Verguet
LAL, Orsay, France

The industrialization and the RF conditioning of 800 power couplers for the European XFEL have been performed by LAL-Orsay from fall 2013 to spring 2016. LAL laboratory has in charge the industrial monitoring, the quality control and the RF conditioning of the couplers fabricated by two different suppliers. It was the first experience of coupler production at such scale. The faced challenges, the different issues, and the lessons learned during the mass production will be reported. And finally the huge amount of RF conditioning data will be shown as one of key point on the conditioning process.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB006

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMB009

Status of the Superconducting Cryomodules and Cryogenic System for the Mainz Energy-recovering Superconducting Accelerator MESA

cryomodule, HOM, niobium, operation

2134

T. Stengler, K. Aulenbacher, F. Hug, D. Simon, P. Weber
IKP, Mainz, Germany
F. Schlander
ESS, Lund, Sweden
N. Wiehl
Johannes Gutenberg University Mainz, Institut of Nuclear Chemistry, Mainz, Germany

Funding: Work supported by the German Research Foundation (DFG) under the Cluster of Excellence "PRISMA"
SRF and the cryogenic system are mandatory for the operation of MESA at the Institut für Kernphysik at Johannes Gutenberg-Universität Mainz. The cryomodule production project is running for one year right now and the recent developments and measurements are presented. Further on the cryogenic concept required for the operation of MESA will be discussed.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB009

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMB012

Production and Investigation of Superconducting 9-Cell Cavity Made of Large Grain Nb in KEK

cavity, SRF, accelerating-gradient, niobium

2141

T. Dohmae, H. Inoue, K. Umemori, Y. Watanabe, M. Yamanaka
KEK, Ibaraki, Japan

For CW operation of superconducting cavity, reduction of heat load at cavity surface is one of important topics, since generated heat load is much higher than that of pulse wave. Using Large Grain (LG) Nb for superconducting cavity has possibility to reach higher Q0 than using Fine Grain Nb, which reduces heat load to 2K Helium. KEK Cavity Fabrication Facility(CFF) group had successfully produced superconducting 1-cell cavity made of LG Nb in 2013, and reached high Q0 at the vertical test (maximum field of 45 MV/m). Then, KEK CFF group started producing first superconducting 9-cell LG cavity in 2015, which will be completed in the end of December 2015. Whole processes of producing this cavity from sliced Nb are done in KEK. In this report, process flow and strategies of producing 9-cell cavity and results of vertical test will be presented in detail.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB012

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMB013

Long Term Cavity Performance in Compact-ERL Injector Cryomodule

cavity, cryomodule, operation, radiation

2145

E. Kako, T. Konomi, T. Miura, H. Sakai, K. Umemori
KEK, Ibaraki, Japan

Degradation of cavity performance due to heavy field emission was observed in three 2-cell cavities after beam operation at 5 MeV for 2 years.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB013

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMB018

Multipactor Simulations in 650 MHz Superconducting Spoke Cavity for an Electron Accelerator

cavity, simulation, multipactoring, laser

2161

T. Kubo, T. Saeki
KEK, Ibaraki, Japan
E. Cenni
CEA/IRFU, Gif-sur-Yvette, France
R. Hajima, M. Sawamura
JAEA, Ibaraki-ken, Japan
H. Hokonohara, Y. Iwashita, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan

Funding: The work is supported by Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan.
In order to realize a compact industrial-use X-ray source based on the laser-Compton scattering, a superconducting spoke cavity for an electron accelerator operated at 4K is under development. While the initially proposed operating frequency was 325MHz considering the 4K operation, we decided to start from the half scale model at 650MHz to accumulate our production experience of spoke cavity within our limited resources. In the present contribution, procedures and results of multipactor simulations for 650MHz spoke cavities are briefly introduced.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB018

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMB026

MHI-MS's Production Activities of Superconducting Cavity

cavity, SRF, gun, superconducting-RF

2180

H. Hara, A. Miyamoto, K. Sennyu, T. Yanagisawa
MHI-MS, Kobe, Japan
E. Kako, T. Konomi, H. Nakai, K. Umemori
KEK, Ibaraki, Japan

Mitsubishi Heavy Industries Mechatronics Systems, Ltd. (MHI-MS), a subsidiary of MHI, took over MHI's accelerator business on October 1, 2015, and has been developing the business since that time. MHI-MS has developed manufacturing process of superconducting cavities continuously. In this presentation, recent progress will be reported.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB026

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMB029

Research of Nitrogen Doping at IHEP

niobium, cavity, vacuum, experiment

2186

P. Sha
Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China
J.P. Dai
IHEP, Beijing, People's Republic of China
F. Jiao
PKU, Beijing, People's Republic of China

Funding: Work funded by National Natural Science Foundation of China, Grant No. 11505197
Recently, nitrogen doping (N-doping) technology has been proved to increase Q0 of superconducting cavity obviously, which lowers the BCS surface resistance. After N-doping, Q0 of 9-cell 1.3 GHz cavity can be increased to 3*10¹⁰ at Eacc = 16 MV/m, while 1.5*1010 without N-doping [1]. Since 2013, there have been over 60 cavities nitrogen doped at FNAL, JLAB and Cornell. The Circular Electron Collider (CEPC) has been proposed by IHEP in China, while requests Q0=4e10@Eacc=15.5 MV/m for 650 MHz cavity. It's hard to achieve without N-doping. So research of N-doping was begun in cooperation with Peking University in early 2015. Experiments of niobium samples have showed that nitrogen concentration at niobium surface increased a lot after N-doping. After then, several single-cell 1.3 GHz cavities completed vertical tests, but there're no successful test results of Q0 increasing, yet.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB029

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMB041

Design of RF Power Coupler for RISP Half Wave Resonator

simulation, impedance, cavity, vacuum

2208

S. Lee, E.-S. Kim
Korea University Sejong Campus, Sejong, Republic of Korea
I. Shin
IBS, Daejeon, Republic of Korea

RF power couplers for half wave resonators are under development for the Rare Isotope Science Project (RISP) in Korea. It is required to deliver up to 6 kW RF power at 162.5 MHz to the HWR in CW mode. The RF coupler is a coaxial capacitive type using a disc type ceramic window. Design studies of 2nd prototype HWR RF coupler are presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB041

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMB047

Higher Order Modes Couplers for 800 MHz Harmonic Cavity

HOM, cavity, damping, multipactoring

2217

Ya.V. Shashkov, R.V. Donetskiy, M. Gusarova, N.P. Sobenin
MEPhI, Moscow, Russia

Funding: *Work supported by Ministry of Education and Science grant 3.245.2014/r
For the higher order modes damping (HOM) in the 800 MHz superconducting single cell cavity the HOM coupler was developed. Several versions of the coupler design were shown. For the chain of two cavities with couplers the calculations of external Q-factor are presented. The calculations of multipactor discharge of cavity were also conducted.
Higher order modes, Tesla, couplers

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB047

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMB049

Transverse Defocusing Study in LPWA Channel for Linear and Bubble Modes

plasma, laser, simulation, acceleration

2224

S.M. Polozov, V.I. Rashchikov, Ya.V. Shashkov
MEPhI, Moscow, Russia

Laser plasma wakefield acceleration (LPWA) is one of most popular novel trends of acceleration. The LPWA has two serous disadvantages as very high energy spread and low part of electrons capturing into acceleration. The waveguide and klystron type beam pre-modulation schemes was proposed *, ** to growth capturing and to limit the energy spectrum of 2-3 % for 200-300 MeV beam. One interesting effect was detected due to numerical simulation of beam dynamics in plasma channel. Not captured electrons are escape to the channel border fast and this effect should be explained. It was shown that such effect is caused by effective potential function which forms very high defocusing transverse field after its trailing edge. The results of such explanation verified by numerical simulations are discussed in report for linear and bubble LPWA modes.
* S.M. Polozov. NIM A, 729, p.517-521, 2013
** S.M. Polozov. Problems of Atomic Science and Technology. Series: Nuclear Physics Investigations, 6 (88), p. 29- 34, 2013

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB049

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMB053

Study of Third Harmonic Cavity for Taiwan Photon Source

cavity, dipole, vacuum, scattering

2237

Z.K. Liu, L.-H. Chang, M.H. Chang, L.J. Chen, PY. Chen, F.-T. Chung, M.-C. Lin, C.H. Lo, C.L. Tsai, M.H. Tsai, Ch. Wang, M.-S. Yeh, T.-C. Yu
NSRRC, Hsinchu, Taiwan

Taiwan Photon Source (TPS) is a modern light source with 3 GeV electron energy and low emittance. The bunch length is about 3 mm at designed beam current of 500 mA and operating gap voltage of 3.2 MV. The short bunch length results in short Touschek lifetime and high parasitic loss of insertion device (ID). Some of the undulators are operated in vacuum at TPS, therefore the head load become an important issue. To install higher harmonic cavity is a solution for improving the Touschek lifetime and the heat load by lengthening the bunch length. The effect of installing 3rd harmonic cavity for TPS is investigated. The expected maximum elongation factor for bunch lengthening, as well as the effect on the Touschek lifetime and heat load of ID are presented in this paper.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB053

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMB060

Modifications to the Pump Out Box to Lower the Qext of Diamond SCRF Cavities

cavity, coupling, operation, simulation

2251

S.A. Pande, C. Christou, P. Gu
DLS, Oxfordshire, United Kingdom
G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom

Diamond's CESR-B cavities are iris coupled and have fixed Qext. For reliability, the cavities are operated at lower voltages. This results in the optimum condition for beam loading being satisfied at a much lower power typically about 100 kW. For operation at 300 mA with two cavities, the RF power needed per system exceeds 200 kW. Consequently, the cavities need to be operated under-coupled. To lower the Qext and move the optimum operating point nearer to 200kW, 3 stub tuners are used in the waveguide feed line. The difference in the height of the coupling waveguide on cavity and that of the vacuum side waveguide on the window assembly results in a step transition which affects the Qext. The present window/step location results in Qext higher than that without the window. The Qext can be lowered by re-locating the RF window or by shifting the step change in the waveguide cross-section from its present location. This needs modification to the Pump Out box. The pros and cons of the proposed modification to the pump out box in terms of standing waves and multipacting characteristics studied with CST Studio are discussed in this paper.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB060

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMR007

Electron Lens Construction for the Integrable Optics Test Accelerator at Fermilab

gun, solenoid, optics, focusing

2271

M.W. McGee, K. Carlson, L.E. Nobrega, G. Stancari, A. Valishev
Fermilab, Batavia, Illinois, USA

Funding: Operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02- 07CH11359 with the U.S. Department of Energy.
The Integrable Optics Test Accelerator (IOTA) is proposed for operation at Fermilab. The goal of IOTA is to create practical nonlinear accelerator focusing systems with a large frequency spread and stable particle motion. The IOTA is a 40 m circumference, 150 MeV (e-), 2.5 MeV (p⁺) diagnostic test ring. Construction of an electron lens for IOTA is necessary for both electron and proton operation. Components required for the Electron Lens design include; a 0.8 T conventional water-cooled main solenoid, and magnetic bending and focusing elements. The foundation of the design relies on repurposing the Fermilab Tevatron Electron Lens II (TELII) gun and collector under ultra-high vacuum (UHV) conditions.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR007

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMR008

Mechanical Stability Study for Integrable Optics Test Accelerator at Fermilab

optics, operation, controls, dipole

2274

M.W. McGee, R. Andrews, K. Carlson, J.R. Leibfritz, L.E. Nobrega, A. Valishev
Fermilab, Batavia, Illinois, USA

Funding: Operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02- 07CH11359 with the U.S. Department of Energy.
The Integrable Optics Test Accelerator (IOTA) is proposed for operation at Fermilab. The goal of IOTA is to create practical nonlinear accelerator focusing systems with a large frequency spread and stable particle motion. The IOTA is a 40 m circumference, 150 MeV (e-), 2.5 MeV (p⁺) diagnostic test ring. A heavy low frequency steel floor girder is proposed as the primary tier for IOTA device component support. Two design lengths; (8) 4 m and (2) 2.8 m long girders with identical cross section completely encompass the ring. This study focuses on the 4 m length girder and the development of a working prototype. Hydrostatic Level Sensor (HLS), temperature, metrology and fast motion measurements characterize the anticipated mechanical stability of the IOTA ring.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR008

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMR014

RF Design of a High Average Beam-Power SRF Electron Source

cavity, SRF, laser, free-electron-laser

2289

N. Sipahi, S. Biedron, S.V. Milton
CSU, Fort Collins, Colorado, USA
I.V. Gonin, R.D. Kephart, T.N. Khabiboulline, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

There is a significant interest in developing high-average power electron sources, particularly in the area of electron sources integrated with Superconducting Radio Frequency (SRF) systems. For these systems, the electron gun and cathode parts are critical components for stable intensity and high-average powers. In this initial design study, we will present the design of a 9-cell accelerator cavity having a frequency of 1.3 GHz and the corresponding field optimization studies.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR014

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMR023

Surface Analysis Studies of Nb3Sn Thin Films

cavity, niobium, SRF, radio-frequency

2316

D.L. Hall, J.J. Kaufman, M. Liepe, J.T. Maniscalco
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

A recent study to optimise the coating of thin-film Nb3Sn cavities has resulted in coating procedures that can fabricate 1.3 GHz cavities capable of reproducibly achieving fields of >16 MV/m with record high Qs >10¹⁰ at 4.2 K. However, the performance of these next generation SRF cavities is as yet well below the theoretical maximum performance expected of Nb3Sn, thus giving ample room for further advancements. Current measurements strongly suggest that the current limits are due to local defects and irregularities in the coated surface. In this paper we analyse, using methods including SEM/EDS, TEM, XRD and EBSD, the surface of both sample coupons and cavity cut-outs, with a view to identifying and understanding the origin of surface non-uniformities that would lead to increased surface resistance and cavity quench.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR023

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMR034

Analyses of 476 MHz and 952 MHz Crab Cavities for JLAB Electron Ion Collider

cavity, ion, collider, betatron

2348

H. Park, A. Castilla, S.U. De Silva, J.R. Delayen
ODU, Norfolk, Virginia, USA
V.S. Morozov
JLab, Newport News, Virginia, USA

Center for Accelerator Science at ODU has designed, fabricated and successfully tested a crab cavity for MEIC at Jefferson Lab*. This proof of principle cavity was based on the earlier MEIC design which used 748.5 MHz RF system. The updated MEIC design** utilizes the components from PEP-II. It results in the change on the bunch repetition rate of stored beam to 476.3 MHz. The ion ring collider will eventually require 952.6 MHz crab cavity. This paper will present the analyses of crab cavities of both 476 MHz and 952 MHz options. It compares advantages and disadvantages of the options which provides the MEIC design team important technical information for a system down selection.
* Cryogenic Test of a 750 MHz Superconducting RF Dipole Crabbing Cavity, A. castilla et al, IPAC2014
** MEIC Design Summary, S. Abeyratne et al, arXiv:1504.07961

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR034

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMR036

Crab Cavities for eRHIC - A Preliminary Design

cavity, proton, linac, luminosity

2351

Q. Wu, I. Ben-Zvi, S. Verdú-Andrés, B. P. Xiao
BNL, Upton, Long Island, New York, USA
I. Ben-Zvi
Stony Brook University, Stony Brook, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The proposed eRHIC electron ion collider at BNL must use a relatively large crossing angle between the ion and electron beams for various reasons, including the reduction of long-range beam-beam effects and minimization of synchrotron radiation noise in the detector. To prevent significant loss of the luminosity due to this large crossing angle, the design of the collider requires the use of groups of crab cavities to provide local crabbing for both proton/ion and electron beams. We will base our design for eRHIC crab cavities based on our experience in the design of the 400 MHz double quarter wave crab cavity (DQWCC) for the Hi-Lumi upgrade of the Large Hadron Collider at CERN. This DQWCC design is scaled to different frequencies of a main crab cavity and its higher harmonics for eRHIC. In this paper, we discuss the preliminary designs of the eRHIC crab cavities and their major parameters.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR036

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMR041

RF and Mechanical Design of 647 MHz 5-Cell BNL4 Cavity for eRHIC ERL

cavity, HOM, linac, SRF

2364

W. Xu, I. Ben-Zvi, H. Hahn, G.T. McIntyre, C. Pai, R. Porqueddu, K.S. Smith, J.L. Tuozzolo, J.E. Tuozzolo, A. Zaltsman
BNL, Upton, Long Island, New York, USA
I. Ben-Zvi
Stony Brook University, Stony Brook, USA

Funding: This work is supported by LDRD program of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
A 647 MHz 5-cell cavity has been designed for the envisioned EIC at BNL which is configured as an eRHIC ERL with a FFAG lattice to achieve the necessary e-p luminosity. The cavity was optimized to allow propagation of all HOMs out of the cavity for high BBU threshold current and low HOM power (loss factor). eRHIC will collide the electron beam over a wide energy range with protons from 40 GeV to 250 GeV, which requires the cavity to tune up to 170 kHz at 2 K. This poses a true challenge to the mechanical design of the SRF cavity. This paper will present the RF and mechanical designs of the 647 MHz 5-cell cavity, and status of the cavity fabrication will be addressed as well.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR041

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMR052

Development of EPICS Control System for ODA Magnet Power Supplies and GigE CCD Camera

controls, linac, EPICS, klystron

2392

S.S. Cha, J.H. Ha, J.H. Kim, Y. Kim
KAERI, Jeongeup-si, Republic of Korea
P. Buaphad
RTX, Daejeon, Republic of Korea
S.D. Yang
Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongup-si, Jeollabuk-do, Republic of Korea

The Radiation Equipment Research Division of the Korea Atomic Energy Research Institute has been op-erating a 10 MeV RF electron linear accelerator, which is used for electron beam irradiation. The beam power and energy of the RF electron linear accelerator are 10 kW and 10 MeV. The accelerator is composed of an electron gun, an S-band (= 2856 MHz) accelerating structure, a klystron, electromagnetic solenoids, a scanning electromagnet, an RF driver, a modulator, and a chiller. The linac components have deteriorated due to a long operation time of 9 years. In this paper, we described Experimental Physics and Industrial Control System (EPICS) to control ODA magnet power sup-plies for solenoids and steering magnets of the 10 MeV electron beam irradiation accelerator.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR052

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMW004

Progress in Detector Design and Installation for Measurements of Electron Cloud Trapping in Quadrupole Magnetic Fields at CesrTA

quadrupole, detector, positron, vacuum

2420

J.A. Crittenden, S. Barrett, M.G. Billing, K.A. Jones, Y. Li, T.I. O'Connell, K. Olear, S. Poprocki, D. L. Rubin, J.P. Sikora
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Work supported by the US National Science Foundation PHY-1416318, PHY-0734867, PHY-1002467, and the U.S. Department of Energy DE-FC02-08ER41538
Following up on our 2013 and 2014 measurements of electron cloud trapping in a quadrupole magnet with 7.4~T/m gradient in the 5.3~GeV positron storage ring at Cornell University, we have redesigned the shielded-stripline time-resolving electron detector and installed a wide-aperture quadrupole magnet at a location in the ring where its field can be compensated by a nearby quadrupole, thus allowing the first measurements of cloud trapping as a function of field gradient. The transverse acceptance of the electron detector has been tripled, allowing tests of model predictions indicating a dramatic cloud splitting effect which exhibits a threshold behavior as a function of bunch population. In addition, a vacuum chamber optimized for cloud buildup measurements using resonant microwave phenomena has been employed. We describe design considerations and modeling predictions for the upcoming 2016 data-taking run. This project is part of the CESR Test Accelerator program, which investigates performance limitations in low-emittance storage and damping rings.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMW004

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMW014

Development of the Electron Cooling Simulation Program for JLEIC

ion, emittance, collider, simulation

2451

H. Zhang, J. Chen, R. Li, Y. Zhang
JLab, Newport News, Virginia, USA
H. Huang, L. Luo
ODU, Norfolk, Virginia, USA

Funding: Work supported by the Department of Energy, Laboratory Directed Research and Development Funding, under Contract No. DE-AC05-06OR23177
In the JLab Electron Ion Collider (JLEIC) project the traditional electron cooling technique is used to reduce the ion beam emittance at the booster ring, and to compensate the intrabeam scattering effect and maintain the ion beam emittance during collision at the collider ring. A new electron cooling process simulation program has been developed to fulfill the requirements of the JLEIC electron cooler design. The new program allows the users to calculate the electron cooling rate and simulate the cooling process with either DC or bunched electron beam to cool either coasting or bunched ion beam. It has been benchmarked with BETACOOL in aspect of accuracy and efficiency. In typical electron cooling process of JLEIC, the two programs agree very well and we have seen a significant improvement of computational speed using the new one. Being adaptive to the modern multicore hardware makes it possible to further enhance the efficiency for computationally intensive problems. The new program is being actively used in the electron cooling study and cooler design for JLEIC. We will present our models and some simulation results in this paper.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMW014

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMW016

Towards a Small Emittance Design of the JLEIC Electron Collider Ring

emittance, dipole, optics, damping

2457

F. Lin, Y.S. Derbenev, A. Hutton, V.S. Morozov, F.C. Pilat, Y. Zhang
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357.
The electron collider ring of the Jefferson Lab Electron-Ion Collider (JLEIC) is designed to provide an electron beam with a small beam size at the IP for collisions with an ion beam in order to reach a desired high luminosity. For a chosen beta-star at the IP, electron beam size is determined by the equilibrium emittance that can be obtained through a linear optics design. This paper briefly describes the baseline design of the electron collider ring reusing PEP-II components and considering their parameters (such as dipole sagitta, magnet field strengths and acceptable synchrotron radiation power) and reports a few approaches to reducing the equilibrium emittance in the electron collider ring.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMW016

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMW019

Study of Beam Synchronization at JLEIC

ion, dipole, collider, proton

2463

V.S. Morozov, Y.S. Derbenev, J. Guo, A. Hutton, Y. Zhang
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contracts No. DE-AC05-06OR23177 and DE-AC02-06CH11357.
The ion collider ring of Jefferson Lab's Electron-Ion Collider (JLEIC) accommodates a wide range of ion energies, from 20 to 100 GeV for protons or from 8 to 40 GeV per nucleon for lead ions. In this medium energy range, ions are not fully relativistic, which means values of their relativistic beta are slightly below 1, leading to an energy dependence of revolution time of the collider ring. On the other hand, electrons with energy 3 GeV and above are already ultra-relativistic such that their speeds are effectively equal to the speed of light. The difference in speeds of colliding electrons and ions in JLEIC, when translated into a path-length difference necessary to maintain the same timing between electron and ion bunches, is quite large. In this paper, we explore schemes for synchronizing the electron and ion bunches at a collision point as the ion energy is varied.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMW019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMW020

Storage-ring Electron Cooler for Relativistic Ion Beams

damping, storage-ring, ion, emittance

2466

F. Lin, Y.S. Derbenev, D. Douglas, J. Guo, G.A. Krafft, V.S. Morozov, Y. Zhang
JLab, Newport News, Virginia, USA
R.P. Johnson
Muons, Inc, Illinois, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357
Application of electron cooling at ion energies above a few GeV has been limited due to reduction of electron cooling efficiency with energy and difficulty in producing and accelerating a high-current high-quality electron beam. A high-current storage-ring electron cooler offers a solution to both of these problems by maintaining high cooling beam quality through naturally-occurring synchrotron radiation damping of the electron beam. However, the range of ion energies where storage-ring electron cooling can be used has been limited by low electron beam damping rates at low ion energies and high equilibrium electron energy spread at high ion energies. This paper reports a development of a storage ring based cooler consisting of two sections with significantly different energies: the cooling and damping sections. The electron energy and other parameters in the cooling section are adjusted for optimum cooling of a stored ion beam. The beam parameters in the damping section are adjusted for optimum damping of the electron beam. The necessary energy difference is provided by an energy recovering SRF structure. A prototype linear optics of such storage-ring cooler is presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMW020

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMW022

Multi-Cell RF-Dipole Deflecting and Crabbing Cavity

cavity, dipole, proton, ion

2469

S.U. De Silva, J.R. Delayen, H. Park
ODU, Norfolk, Virginia, USA

Single cell superconducting rf-dipole cavities operating at 400 MHz, 499 MHz and 750 MHz have been designed, fabricated and successfully tested at cryogenic temperatures. These cavities have been shown to have attractive rf properties: high deflecting gradients, low electric and magnetic peak surface fields, and high shunt impedance. The single cell rf-dipole geometry has no lower order modes and has widely separated higher order mode spectrum. In this study we are investigating a multi-cell superconducting rf-dipole cavity operating at 952.6 MHz intended for the Jefferson Lab Energy Electron-Ion Collider. The analysis investigates the dependence of beam aperture variation and other cavity parameters on rf properties including cavity gradient, surface fields, shunt impedance and higher order mode separation.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMW022

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMW023

Higher Luminosity eRHIC Ring-Ring Options and Upgrade

luminosity, emittance, quadrupole, linac

2472

R.B. Palmer, J.S. Berg, M. Blaskiewicz, A.V. Fedotov, C. Montag, B. Parker, H. Witte
BNL, Upton, Long Island, New York, USA

Funding: This manuscript has been authored by employees of Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
Lower risk ring-ring alternatives to the BNL linac-ling~[linacring] eRHIC electron ion collider (EIC) are discussed. The baseline from the Ring-Ring Working Group~[ringring] has a peak proton-electron luminosity of ≈§I{1.2e33}{cm^-2.s^-1}. An option has final focus quadrupoles starting immediately after the detector at 4.5~m, instead of at 32~m in the baseline. This allows the use of lower β^*s. It also uses more, 720, lower intensity, bunches, giving reduced IBS emittance growth and requiring only low energy pre-cooling. It has a peak luminosity of ≈§I{7e33}{cm^-2.s^-1}. An upgrade of this option, requiring magnetic, or coherent, electron cooling, has 1440 bunches and peak luminosity of ≈§I{15e33}{cm^-2.s^-1}.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMW023

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMW025

Optimizing the Design of Linear Non-scaling Fixed Field Alternating Gradient Arcs for the Electron Rings of eRHIC

radiation, synchrotron, synchrotron-radiation, lattice

2475

J.S. Berg
BNL, Upton, Long Island, New York, USA

Funding: This manuscript has been authored by employees of Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
I describe a process for producing optimal linear non-scaling fixed field alternating gradient (FFAG) arc designs for the electron rings of eRHIC, an electron-ion collider in the RHIC tunnel at Brookhaven National Laboratory. The electrons are accelerated in two FFAG rings (low and high energy), which in addition to the arcs optimized here, contain straight sections, splitter/combiner sections, and a linac shared between the rings. The optimization process I use has two layers, an inner one meeting constraints and an outer optimization that minimizes a target function. The target function is an approximation to the FFAG arc cost, for which I give the function used and the basis for that choice. While reducing synchrotron radiation is important, I show that optimizing for synchrotron radiation alone leads to significant cost an performance penalties for the rest of the machine design for very little reduction in synchrotron radiation. I describe important constraints on the design, in particular minimum drift lengths, maximum and minimum tunes, and clearance from the beam to the beam pipe. Finally, I present possible eRHIC FFAG parameters resulting from this optimization.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMW025

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMW026

Beam-Beam Simulation With Crab-Cavities for Erhic

proton, dynamic-aperture, luminosity, cavity

2479

Y. Luo, Y. Hao, Y.C. Jing, V. Ptitsyn, D. Trbojevic
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
To avoid the luminosity loss due to cross-angle collision, crab cavities are being considered for the electron-ion collider designs at Brookhaven National Laboratory. In this article, we study the effects of crab cavities on the proton beam dynamics without and with beam-beam interactions. Dynamic apertures are to be calculated with various parameters of crab cavities. To minimize the distortion from a single crab cavity, harmonic crab cavities are also considered.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMW026

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMW027

The ERL-based Design of Electron-Hadron Collider eRHIC

hadron, linac, luminosity, proton

2482

V. Ptitsyn, E.C. Aschenauer, I. Ben-Zvi, J.S. Berg, M. Blaskiewicz, S.J. Brooks, K.A. Brown, J.C. Brutus, O.V. Chubar, A.V. Fedotov, D.M. Gassner, H. Hahn, Y. Hao, A. Hershcovitch, H. Huang, W.A. Jackson, Y.C. Jing, R.F. Lambiase, V. Litvinenko, C. Liu, Y. Luo, G.J. Mahler, B. Martin, G.T. McIntyre, W. Meng, F. Méot, T.A. Miller, M.G. Minty, B. Parker, I. Pinayev, V.H. Ranjbar, T. Roser, J. Skaritka, R. Than, P. Thieberger, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, E. Wang, G. Wang, H. Witte, Q. Wu, C. Xu, W. Xu, A. Zaltsman
BNL, Upton, Long Island, New York, USA
S.A. Belomestnykh
Fermilab, Batavia, Illinois, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Recent developments of the ERL-based design of future high luminosity electron-hadron collider eRHIC focused on balancing technological risks present in the design versus the design cost. As a result a lower risk design has been adopted at moderate cost increase. The modifications include a change of the main linac RF frequency, reduced number of SRF cavity types and modified electron spin transport using a spin rotator. A luminosity-staged approach is being explored with a Nominal design (L ~ 10³³ cm^-2 s^-1) that employs reduced electron current and could possibly be based on classical electron cooling, and then with the Ultimate design (L > 10³⁴ cm^-2 s^-1) that uses higher electron current and an innovative cooling technique (CeC). The paper describes the recent design modifications, and presents the full status of the eRHIC ERL-based design.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMW027

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMW028

First Attempts at using Active Halo Control at the LHC

emittance, simulation, controls, collimation

2486

J.F. Wagner
Goethe Universität Frankfurt, Frankfurt am Main, Germany
R. Bruce, H. Garcia Morales, W. Höfle, G. Kotzian, R. Kwee-Hinzmann, A. Langner, A. Mereghetti, E. Quaranta, S. Redaelli, A. Rossi, B. Salvachua, R. Tomás, G. Valentino, D. Valuch, J.F. Wagner
CERN, Geneva, Switzerland
G. Stancari
Fermilab, Batavia, Illinois, USA

Funding: Research supported by the High Luminosity LHC project.
The beam halo population is a non-negligible factor for the performance of the LHC collimation system and the machine protection. In particular this could become crucial for aiming at stored beam energies of 700 MJ in the High Luminosity (HL-LHC) project, in order to avoid beam dumps caused by orbit jitter and to ensure safety during a crab cavity failure. Therefore several techniques to safely deplete the halo, i.e. active halo control, are under development. In a first attempt a novel way for safe halo depletion was tested with particle narrow-band excitation employing the LHC Transverse Damper (ADT). At an energy of 450 GeV a bunch selective beam tail scraping without affecting the core distribution was attempted. This paper presents the first measurement results, as well as a simple simulation to model the underlying dynamics.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMW028

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMW039

JLEIC SRF Cavity RF Design

cavity, impedance, HOM, damping

2522

S. Wang, J. Guo, R.A. Rimmer, H. Wang
JLab, Newport News, Virginia, USA

The initial design of a low higher order modes (HOM) impedance superconducting RF (SRF) cavity is presented in this paper. The design of this SRF cavity is for the proposed Jefferson Lab Electron Ion Collider (JLEIC). The electron ring of JLEIC will operate with electrons of 3 to 10 GeV energy. The ion ring of JLEIC will operate with protons of up to 100 GeV energy. The bunch lengths in both rings are ~12 mm (RMS). In order to maintain the short bunch length in the ion ring, SRF cavities are adopted to provide large enough gradient. In the first phase of JLEIC, the PEP II RF cavities will be reused in the electron ring to lower the initial cost. The frequency of the SRF cavities is chosen to be the second harmonic of PEP II cavities, 952.6 MHz. In the second phase of JLEIC, the same frequency SRF cavities may replace the normal conducting PEP II cavities to achieve higher luminosity at high energy. At low energies, the synchrotron radiation damping effect is quite weak, to avoid the coupled bunch instability caused by the intense closely-spaced electron bunches, low HOM impedance of the SRF cavities combined with longitudinal feedback system will be necessary.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMW039

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMW041

Multiple Bunch HOM Evaluation for eRHIC Main Linac Cavities

HOM, cavity, linac, proton

2525

C. Xu, I. Ben-Zvi, M. Blaskiewicz, Y. Hao, V. Ptitsyn
BNL, Upton, Long Island, New York, USA

Funding: This work is supported by LDRD program of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
High current Superconducting Radiofrequency (SRF) 5-cell cavities are essential for the proposed ERL-based electron-ion collider eRHIC in BNL. The HOM power generated when a single bunch traverses the cavity is estimated by the corresponding loss factor. Multiple re-circulations through the ERL create a specific bunch pattern. In this case the loss factor can be different than the single bunch loss factor. The HOM power generation can be surveyed in the time and frequency domains. We estimate the average HOM power in the eRHIC 5-cell cavity with different ERL bunch patterns using both methods. We also discuss possible solutions to reduce this HOM power.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMW041

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMW042

Trapped Modes Study and BBU Analysis in the 5-Cell 650 MHz Cavity

HOM, cavity, impedance, damping

2529

C. Xu, I. Ben-Zvi, Y. Hao, V. Ptitsyn, W. Xu
BNL, Upton, Long Island, New York, USA
I. Petrushina
SUNY SB, Stony Brook, New York, USA

Funding: This work is supported by LDRD program of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. #chenxu@bnl.gov
eRHIC project is a future electron-hadron collider proposed at BNL. The proposed electron accelerator will generate up to 20 GeV polarized electrons which will collide with proton beams with energy up to 250 GeV. The proposed collider will deliver electron-nucleon luminosity of 10³³- 10³⁴ cm^-2 ses⁻¹. A superconducting RF (SRF) 5-cell elliptical cavity will be utilized in electron accelerator. This paper presents a study of higher-order modes (HOM) for this 647 MHz SRF cavity. Different types of HOM modes and their BBU instabilities were investigated for frequencies up to 3.2 GHz. Threshold current values of beam breakup are estimated by GBBU code. Further improvement on this threshold current has been explored and discussed.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMW042

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMW043

Frequency Scaling Study of Crab Cavity for Future Colliders with Crab Crossing

cavity, luminosity, ion, collider

2532

Y. Hao, V. Ptitsyn
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Crab crossing is an essential concept in the newly proposed colliders or the upgrades. It enables crossing angles to achieve lower β^* without a loss of luminosity. The frequency of the crab cavity shall be chosen with various considerations, including the luminosity degradation, emittance growth due to synchro-beta resonances and RF noises. We use the figure of merits and related simulation to establish the frequency scaling relations with important beam parameters, which guide the choice of crab cavity frequency for new designs.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMW043

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMW044

Start-to-End Simulation of eRHIC ERL

linac, simulation, emittance, synchrotron-radiation

2535

Y. Hao, S.J. Brooks, Y.C. Jing, F. Méot, V. Ptitsyn, D. Trbojevic, N. Tsoupas
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The ERL-ring eRHIC adopts the electron accelerator design of a multi-pass energy recovery linac (ERL), with fixed field alternating gradient (FFAG) recirculating passes. To ensure the beam quality in the accelerating and decelerating stage and the energy recovery efficiency, detailed start-to-end simulation is required to evaluate the various beam dynamics effects, such as synchrotron radiation, wake fields, coherent synchrotron radiation. In this paper, we present the eRHIC ERL start-to-end simulation strategy with various simulation codes and the current status.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMW044

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMY002

SLRI Beam Test Facility Development Project

target, synchrotron, detector, booster

2539

K. Kittimanapun, N. Chanlek, S. Cheedket, N. Juntong, P. Klysubun, S. Krainara, K. Sittisard, S. Supajeerapan
SLRI, Nakhon Ratchasima, Thailand

Funding: This work is supported by the National Science and Technology Development Agency (NSTDA) under contract FDA-C0-2558-855-TH.
The SLRI Beam Test Facility (SLRI BTF) is a part of the future upgrades of the SLRI accelerator complex. Upon completion, SLRI BTF will be able to produce electron test beams with the number of electrons ranging from a few to several thousand electrons per bunch. The project is divided into three stages based on the complexity of the electron reduction setups. The simple setup for the initial stage has been implemented without any modifications to the current high-energy beam transport line (HBT) while additional elements together with an existing 4-degree dipole are required for the short-term setup in the second stage. For the last stage, a new dedicated transfer line equipped with a high-resolution energy selector will be constructed to direct the electron beam from the HBT beam line to an experimental station. This project aims to provide a defined number of electrons with maximum energy of 1 GeV for calibration and testing of high energy detectors as well as other beam diagnostic instrumentations.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY002

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMY003

Simulations of the Acceleration of Externally Injected Electrons in a Plasma Excited in the Linear Regime

plasma, laser, acceleration, experiment

2542

N. Delerue, C. Bruni, S. Jenzer
LAL, Orsay, France
S. Kazamias, B. Lucas, G. Maynard
Laboratoire de Physique des Gaz et des Plasmas, Universite Paris-Sud, Orsay, France
M. Pittman
CLUPS, Orsay, France

We have investigated numerically the coupling between a 10 \si{MeV} electron bunch of high charge (§I{> 100}{pc}) with a laser generated accelerating plasma wave. Our results show that a high efficiency coupling can be achieved using a §I{50}{TW}, §I{100}{μ \meter} wide laser beam, yielding accelerating field above §I{1}{ GV/m}. We propose an experiment where these predictions could be tested.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY003

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMY004

Development of an Injector and a Magnetic Transfer Line in the Framework of Cilex

laser, plasma, dipole, acceleration

2545

A. Chancé
CEA/DSM/IRFU, France
T. Audet, B. Cros, P. Lee, G. Maynard
Laboratoire de Physique des Gaz et des Plasmas, Universite Paris-Sud, Orsay, France
M. Bougeard, S. Dobosz-Dufrénoy, A. Maitrallain
CEA, Gif-sur-Yvette, France
N. Delerue
LAL, Orsay, France
O. Delferrière, A. Mosnier, J. Schwindling
CEA/IRFU, Gif-sur-Yvette, France
P. Monot
CEA/DSM, Gif-sur-Yvette, France
A. Specka
LLR, Palaiseau, France

Funding: Investments for the Future program under reference ANR-10-EQPX-25, by the Triangle de la Physique under contract 2011-086TMULTIPLACCELE, 2012-032TELISA, and by the Labex PALM and P2IO.
Laser plasma accelerators (LPAs) have proven their capability to produce accelerating gradients three orders of magnitude higher than RF cavity-based accelerators. The present challenges of LPAs are to achieve the beam quality and stability required by users and to show the feasibility of plasma staging for high-energy applications. As one of the experiments planned at the PetaWatt laser APOLLON facility, currently under construction in France, aims at testing the two-stage scheme, a dedicated plasma injector which will be used as the first stage has been developed and tested at the UHI100 facility at CEA Saclay. The electron source, as well as the beam characterization line, will be presented and the first results will be discussed.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY004

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMY005

Upgrades of the Experimental Setup for Electron Beam Self-modulation Studies at PITZ

plasma, laser, experiment, acceleration

2548

M. Groß, J. Engel, G. Koss, O. Lishilin, G. Loisch, G. Pathak, S. Philipp, R. Schütze, F. Stephan
DESY Zeuthen, Zeuthen, Germany
R. Brinkmann, J. Osterhoff
DESY, Hamburg, Germany
F.J. Grüner
CFEL, Hamburg, Germany
F.J. Grüner
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
D. Richter
HZB, Berlin, Germany
C.B. Schroeder
LBNL, Berkeley, California, USA

The self-modulation instability is fundamental for the plasma wakefield acceleration experiment of the AWAKE collaboration at CERN where this effect is supposed to be used to generate proton bunches short enough for producing high acceleration fields. For ease of experimentation it was decided to set up a supporting experiment at the electron accelerator PITZ (Photo Injector Test facility at DESY, Zeuthen site), given that the underlying physics is the same. The goals are to demonstrate and investigate in detail the self-modulation of long electron beams. In 2015 a first set of experiments was conducted utilizing as key elements a novel cross-shaped lithium plasma cell and an ArF excimer laser for plasma generation. No self-modulation was observed yet because of various experimental shortcomings. The properties of the experimental setup were studied in detail and in this contribution we report about the upgrades which are projected to enable the observation of the self-modulation in the upcoming experimental run.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY005

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMY007

Plasma Density Profile Characterization for Resonant Plasma Wakefield Acceleration Experiment at SPARC_LAB

plasma, laser, acceleration, experiment

2554

F. Filippi
INFN-Roma1, Rome, Italy
M.P. Anania, A. Biagioni, E. Chiadroni, M. Ferrario
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
INFN-Roma II, Roma, Italy
F. Filippi, A. Giribono, A. Mostacci, L. Palumbo
University of Rome La Sapienza, Rome, Italy
F. Filippi, A. Giribono, A. Mostacci, L. Palumbo
INFN-Roma, Roma, Italy
A. Giribono
University of Rome "La Sapienza", Rome, Italy
A. Zigler
The Hebrew University of Jerusalem, The Racah Institute of Physics, Jerusalem, Israel

New generation of particle accelerators is based on the excitation of large amplitude plasma waves driven by either electron or laser beams, named as Plasma Wakefield Accelerator (PWFA) and Laser Wakefield Accelerator (LWFA), respectively. Future experiments scheduled at the SPARC_LAB test facility aim to demonstrate the acceleration of externally injected high brightness electron beams through both schemes. In particular, in the so-called resonant PWFA a train of more than two driver electron bunches generated with the laser comb technique resonantly excites wakefields into the plasma, the last bunch (witness) is injected at the proper accelerating phase gaining energy from the wake. The quality of the accelerated beam depends strongly on plasma density and its distribution along the acceleration length. The desired density can be achieved with a correct shaping of the capillary in which plasma is formed. The measurements of plasma density, as well as other plasma characteristics, can be performed with spectroscopic measurements of the plasma self emitted light. The measurement of density distribution for hydrogen filled capillaries is here reported.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY007

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMY008

Towards Awake Applications: Electron Beam Acceleration in a Proton Driven Plasma Wake

plasma, proton, acceleration, wakefield

2557

E. Adli
University of Oslo, Oslo, Norway

The first phases of the AWAKE experiment will study the wake structure and the potential for electron acceleration in a self-modulated proton driver. In AWAKE Run 2, expected to start after the LHC Long Shut Down 2, electron beam acceleration will be studied. Using a single proton driver and a long acceleration stage, an electron bunch will be accelerated to high energies. Demonstrating beam quality preservation and scalable plasma sources will be a significant step towards using proton driven plasma for applications. We report on the plans and preparations for AWAKE Run 2.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY008

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMY011

Compact Laser Plasma Accelerator at Peking University

laser, plasma, acceleration, target

2569

L.R.F. Li, J.E. Chen, S.C. Gao, Y.X. Geng, Q. Liao, J B. Liu, H.Y. Lu, X.Q. Yan, Y.Y. Zhao, Y.Y. Zhu
PKU, Beijing, People's Republic of China
Y.R. Shou
Peking University, School of Physics, Beijing, People's Republic of China

A brand new and solely accelerator based on the interaction physics of high intensity ultrafast laser and plasmas, named Compact LAser Plasma Accelerator (CLAPA), was recently built. The laser system can deliver 5J/25fs @ 800nm pulses with contrast of 10^-10. Experiments on electron acceleration is scheduled with the regime of laser wakefield acceleration. The charge and the energy spread of the accelerated electron beams will be concerned mainly. The experiments is planned with gas targets with single and dual stages. For the single stage acceleration, we will try density ramp injection and a loose focusing for a monoenergetic electron beam with more charge for some applications. With the PIC simulations and new injection methods, it is expected to generate GeV/tens pC electron beam with an energy spread of <1%. For the two stage cascaded acceleration, we will focus on the staged acceleration and control of the injection of the second stage, as well as the acceleration length of the second stage by manipulating the parameters of the gas target as well as the laser itself. The far future goal of the second plan is to develop a designable and applicable accelerators.
* W.Lu, Phys. Rev.ST Accel. Beams 10.061301 （2007）
** J. Faure, Nature 431, 541 (2004)
***J.S. Liu, Phys. Rev. Lett 107, 035001 (2011)

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY011

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMY014

Feasibility Study of a Laser-Driven High Energy Electron Acceleration in a Long Up-Ramp Density

plasma, laser, simulation, acceleration

2576

M. Kim, J. Kim, S.W. Lee, I.H. Nam, H. Suk
GIST, Gwangju, Republic of Korea

Laser-driven wakefield acceleration (LWFA) has received much attention as it can produce GeV-level high-energy electrons in cm-scale distance*. However, the accelerated electron energies are still limited by several factors, especially by the dephasing problem that is caused by different velocities between the plasma wake wave and the accelerated electron beam. In order to increase the acceleration length restricted by the dephasing problem**, we developed a gas-cell with density-tapering, which is realized by applying different gas pressures into two gas inlets in the gas cell. In this way, the gas density and gradient can be easily controlled in the gas cell. We used the density-tapered gas-cell for laser wakefield acceleration experiments in our laboratory with a 20 TW/40 fs Ti:sapphire laser system***. The results show that the electron energy can be significantly enhanced (about twice) with the tapered density gas-cell, compared with a uniform density conventional gas-cell. In this presentation, we show the experimental results and comparison with two-dimensional (2-D) particle-in-cell (PIC) simulation results.
* W. P. Leemans et al. Phy. Rev. Lett. 113, 245002 (2014).
** M. S. Kim et al. Appl. Phy. Lett. 102, 204103 (2013).
*** I. H. Nam et al. Curr. Appl. Phy. 15, 468 (2015).

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY014

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMY015

Numerical Studies on Tunable Coherent Radiations with a Laser-Plasma Accelerator

plasma, laser, radiation, acceleration

2579

J. Kim, M. Kim, I.H. Nam, H. Suk
GIST, Gwangju, Republic of Korea
M.S. Hur
UNIST, Ulsan, Republic of Korea

Generation of tunable coherent radiation is numerically investigated via the two-dimensional particle-in-cell (2D-PIC) code developed by UNIST* and SIMPLEX developed by Spring-8. The electron beams can be produced by the laser-driven wakefield acceleration technique. The electron beam energy can be easily adjusted between 450 MeV and 800 MeV with a tapered density plasma on the order of 1×10¹⁸ cm^-3 while the driving laser power is fixed, and the high-energy electron beams can be sent through the undulator arrays for the coherent light emission. The energy-controllable electron bunches can provide an opportunity to control the radiation wave-length with the fixed gap undulators. For the tapered density profile, a capillary cell with two gas inlets can be used. In this paper, we show some simulation and numerical research results regarding these issues, which reveal the possibility for a tunable light source in the soft X-ray regime.
* M. S. Hur, H. Suk, Phys. Plasmas 18 033102 (2011).

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY015

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMY017

Numerical Studies of Self Modulation Instability in the Beam-driven Plasma Wakefield Experiments

plasma, proton, wakefield, simulation

2585

K. Moon, M. Chung
UNIST, Ulsan, Republic of Korea

Proton beam-driven plasma wakefield acceleration was recently proposed as a way to bring electrons to TeV energy range in a single plasma section. When the ultra-relativistic long proton beam propagates into the plasmas, this bunch splits into many small bunches. This phenomenon is known as a Self-Modulation Instability (SMI), and its characteristics depend on the ratio of bunch length and plasma wavelength. In this study, we first introduce a Particle-In-Cell (PIC) code WARP, focusing on the basis of parallel version structure. Through numerical simulations using the WARP, we investigate the characteristics of the SMI and propose possible experimental setup at the Injector Test Facility (ITF) of Pohang Accelerator Laboratory (PAL). Also, we present dependencies of the witness beam quality on both the driver beam and plasma parameters.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY017

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMY019

AWAKE, the Advanced Proton Driven Plasma Wakefield Acceleration Experiment

plasma, wakefield, laser, experiment

2588

P. Muggli
MPI, Muenchen, Germany
C. Bracco
CERN, Geneva, Switzerland

The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) aims at studying plasma wakefield generation and electron acceleration driven by proton bunches. It is a proof-of-principle R&D experiment at CERN and the world's first proton driven plasma wakefield acceleration experiment. The AWAKE experiment is currently being installed in the former CNGS facility and will use the 400 GeV/c proton beam bunches from the SPS to drive the wakefields in the plasma. The first experiments will focus on the self-modulation instability of the long (rms ~12 cm) proton bunch in the plasma. These experiments are planned for the end of 2016. Later, in 2017/2018, low energy (~15 MeV) electrons will be externally injected to sample the wakefields and be accelerated with GeV/m gradients. The main goals of the experiment will be summarized. A summary of the AWAKE design and construction status will be presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMY020

Integration of a Terawatt Laser at the CERN SPS Beam for the AWAKE Experiment on Proton-Driven Plasma Wake Acceleration

laser, plasma, proton, vacuum

2592

V. Fedosseev, M. Battistin, E. Chevallay, N. Chritin, V. Clerc, T. Feniet, F. Friebel, F. Galleazzi, P. Gander, E. Gschwendtner, J. Hansen, C. Heßler, M. Martyanov, A. Masi, A. Pardons, F. Salveter, K.A. Szczurek
CERN, Geneva, Switzerland
M. Martyanov, J.T. Moody, P. Muggli
MPI-P, München, Germany

In the AWAKE experiment a high-power laser pulse ionizes rubidium atoms inside a 10 m long vapor cell thus creating a plasma for proton-driven wakefield acceleration of electrons. Propagating co-axial with the SPS proton beam the laser pulse seeds the self-modulation instability within the proton bunch on the front of plasma creation. The same laser will also generate UV-pulses for production of a witness electron beam using an RF-photoinjector. The experimental area formerly occupied by CNGS facility is being modified to accommodate the AWAKE experiment. A completely new laser laboratory was built, taking into account specific considerations related to underground work. The requirements for AWAKE laser installation have been fulfilled and vacuum beam lines for delivery of laser beams to the plasma cell and RF-photoinjector have been constructed. First results of laser beam hardware commissioning tests following the laser installation will be presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY020

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMY021

Beam-Plasma Interaction Simulations for the AWAKE Experiment at CERN

plasma, proton, experiment, wakefield

2596

A.V. Petrenko, E. Gschwendtner, G. Plyushchev, M. Turner
CERN, Geneva, Switzerland
K.V. Lotov
BINP SB RAS, Novosibirsk, Russia
K.V. Lotov, A. Sosedkin
NSU, Novosibirsk, Russia
G. Plyushchev
EPFL, Lausanne, Switzerland
M. Turner
TUG/ITP, Graz, Austria

The AWAKE experiment at CERN will be the first proof-of-principle demonstration of the proton-driven plasma wakefield acceleration using the 400 GeV proton beam extracted from the SPS accelerator. The plasma wakefield will be driven by a sequence of sub-millimeter long micro-bunches produced as a result of the self-modulation instability (SMI) of the 12 cm long SPS proton bunch in the 10 m long rubidium plasma with a density corresponding to the plasma wavelength of around 1 mm. A 16 MeV electron beam will be injected into the developing SMI and used to probe the plasma wakefields. The proton beam self-modulation in a wide range of plasma densities and gradients have been studied in detail via numerical simulations. A new configuration of the AWAKE experiment with a small plasma density step is proposed.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMY022

Homogeneous Focusing of Train of Short Relativistic Electron Bunches by Plasma Wakefield

focusing, plasma, wakefield, simulation

2599

V.I. Maslov, I.N. Onishchenko
NSC/KIPT, Kharkov, Ukraine
I.P. Levchuk (Yarovaya)
KhNU, Kharkov, Ukraine

The focusing of bunches by wakefield, excited in plasma by resonant sequence of relativistic electron bunches (repetition frequency of the bunches coincides with the plasma frequency), is inhomogeneous. In this paper we investigate wakefield plasma lens, in which all bunches of sequence are focused identically and uniformly, for short relativistic electron bunches. For this it is necessary that the charge of 1-st bunch is smaller in determined times than the charges of the other bunches, the interval between back front of 1-st bunch and 1-st front of 2-nd bunch equals determined value, the interval between back front of N-th bunch and 1-st front of (N+1)-th bunch for all other bunches is multiple to excited wavelength. It is shown that only 1-st bunch is in finite Ez≠0. Other bunches are in zero longitudinal electrical wakefield. Hence the 1-st bunch interchange by energy with wakefield. The subsequent bunches don't interchange by energy with wakefield and the amplitude of wakefield doesn't change along sequence. Radial wake force Fr in regions, occupied by bunches, is approximately constant along bunches.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY022

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMY023

Self-focusing and Wakefield-focusing of Relativistic Electron Bunches in Plasma

focusing, wakefield, plasma, space-charge

2602

V.I. Maslov, I.P. Levchuk (Yarovaya), I.N. Onishchenko
NSC/KIPT, Kharkov, Ukraine

It was shown that at the wakefield excitation by electron bunch, the length of which is equal to half of the wavelength, the ratio of wakefield focusing to self-focusing is large at the end of the bunch, the shape of which is such that it falls from the current maximum value in the head of the bunch to zero at the end of the bunch. However, the ratio of wakefield focusing to self-focusing tends to zero at the end of the bunch, if the current increases along the bunch from zero in the head of the bunch to a maximum value at the end of the bunch. In the case of homogeneous bunch with sharp edges, the length of which is several plasma wavelength, the self-focusing force Fs is constant along the bunch, and wakefield force of focusing changes from -Fs to Fs. In the case of homogeneous bunch with precursor of half current and length, equal to half of wavelength, focusing of bunch is determined by the homogeneous self-focusing force and wakefield focusing force equals zero. Cases of rectangular and Gaussian bunches, the length of which is equal to half of wavelength, also were considered.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY023

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMY024

A Spectrometer for Proton Driven Plasma Accelerated Electrons at AWAKE - Recent Developments

plasma, proton, emittance, simulation

2605

L.C. Deacon, S. Jolly, F. Keeble, M. Wing
UCL, London, United Kingdom
B. Biskup, A. Goldblatt, S. Mazzoni, A.V. Petrenko
CERN, Geneva, Switzerland
B. Biskup
Czech Technical University, Prague 6, Czech Republic
M. Wing
DESY, Hamburg, Germany
M. Wing
University of Hamburg, Hamburg, Germany

The AWAKE experiment is to be constructed at the CERN Neutrinos to Gran Sasso facility (CNGS). This will be the first experiment to demonstrate proton-driven plasma wakefield acceleration. The 400 GeV proton beam from the CERN SPS will excite a wakefield in a plasma cell several meters in length. To probe the plasma wakefield, electrons of 10–20 MeV will be injected into the wakefield following the head of the proton beam. Simulations indicate that electrons will be accelerated to GeV energies by the plasma wakefield. The AWAKE spectrometer is intended to measure both the peak energy and energy spread of these accelerated electrons. Results of beam tests of the scintillator screen output are presented, along with tests of the resolution of the proposed optical system. The results are used together with a BDSIM simulation of the spectrometer system to predict the spectrometer performance for a range of possible accelerated electron distributions.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY024

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMY025

iMPACT, Undulator-Based Multi-Bunch Plasma Accelerator

plasma, undulator, wakefield, simulation

2609

O. Mete Apsimon, K. Hanahoe, G.X. Xia
UMAN, Manchester, United Kingdom
G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
B. Hidding
USTRAT/SUPA, Glasgow, United Kingdom
J.D.A. Smith
Tech-X, Boulder, Colorado, USA

Funding: This work is supported by the Cockcroft Institute Core Grant and STFC.
The accelerating gradient measured in laser or electron driven wakefield accelerators can be in the range of 10-100GV/m, which is 2-3 orders of magnitude larger than can be achieved by conventional RF-based particle accelerators. However, the beam quality preservation is still an important problem to be tackled to ensure the practicality of this technology. In this global picture, the main goals of this study are planning and coordinating a physics program, the so-called iMPACT, that addresses issues such as emittance growth mechanisms in the transverse and longitudinal planes through scattering from the plasma particles, minimisation of the energy spread and maximising the energy gain while benchmarking the milestones. In this paper, a summary and planning of the project is introduced and initial multi-bunch simulations were presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY025

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMY031

The Production of Negative Carbon Ions with a Volume Cusp Ion Source

ion, extraction, plasma, ion-source

2620

S.V. Melanson, M.P. Dehnel, C. Hollinger, P.T. Jackle, J.A. Martin, D.E. Potkins, T.M. Stewart, J.E. Theroux
D-Pace, Nelson, British Columbia, Canada
T.L. Jones, H.C. McDonald, C. Philpott
BSL, Auckland, New Zealand

Recent progress has been made at the newly commissioned Ion Source Test Facility (ISTF). Phase II, the final phase of the project, was completed in March 2016. First measurements were performed with D-Pace's TRIUMF licensed H⁻ ion source. The source was first characterized with H⁻ and an extraction study of the H⁻ ions was performed. A study of the production of heavy negative ions with volume cusp sources was started. Measurements with helium revealed no negative ions were extracted. Negative carbon ions were produced with acetylene. The beam composition has been analysed with a spectrometer.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY031

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMY032

A PID Control Algorithm for Filament-Powered Volume-Cusp Ion Sources

controls, ion, ion-source, plasma

2623

S.V. Melanson, M.P. Dehnel, C. Hollinger, J.A. Martin, D.E. Potkins
D-Pace, Nelson, British Columbia, Canada
C. Philpott
BSL, Auckland, New Zealand

Volume-cusp ion sources require a fast and precise control algorithm to ensure the arc current, and thus the beam current is stable for high-power industrial DC operation. Using D-Pace's TRIUMF [1] licensed filament-powered H volume-cusp ion source, a proportional-integral-derivative (PID) control algorithm was implemented that provides a peak-to-peak beam current variation of ±0.45 % and a root mean square error of 0.025 mA for 10.16 mA of beam current over 60 minutes. The PID parameters were tuned for different set points and the performance of the algorithm is compared for the different settings. Measured arc current stability, and measured beam current as a function of time are presented and the algorithm utilized is described in detail.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY032

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMY035

Preliminary Commissioning Results of the Proton Source for ESS at INFN-LNS

plasma, proton, diagnostics, vacuum

2628

L. Celona, L. Allegra, A. Amato, G. Calabrese, A.C. Caruso, G. Castro, F. Chines, G. Gallo, S. Gammino, O. Leonardi, A. Longhitano, G. Manno, S. Marletta, D. Mascali, A. Maugeri, M. Mazzaglia, L. Neri, S. Passarello, G. Pastore, A. Seminara, A.S. Spartà, G. Torrisi, S. Vinciguerra
INFN/LNS, Catania, Italy
S. Di Martino, P. Nicotra
Si.A.Tel SRL, Catania, Italy
A. Longhitano
ALTEK, San Gregorio (CATANIA), Italy
G. Torrisi
Universitá Mediterranea di Reggio Calabria, Reggio Calabria, Italy

At Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud (INFN-LNS) - the commissioning of the high intensity Proton Source for the European Spallation Source (PS-ESS) is under way. Preliminary results of plasma diagnostics collected on a testbench called "Flexible Plasma Trap" (FPT) will be correlated to the peculiarities of the magnetic system design and of the microwave injection setup with a view of the possible implications on the beam extraction system. The status of the costruction is presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY035

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMY039

Time Response Measurements for Transmission-Type GaAs/GaAsP Superlattice Photocathodes

laser, cavity, brightness, gun

2641

N. Yamamoto, X.J. Jin
KEK, Ibaraki, Japan
M. Hosaka, Y. Takashima, K. Yamaguchi
Nagoya University, Nagoya, Japan
M. Katoh
UVSOR, Okazaki, Japan

Polarized electron beam is essential for future electron-positron colliders and electron-ion colliders. Recently we have developed the strain compensated superlattice (SL) photocathode. In the strain compensated SLs, the equivalent compressive and tensile strains introduced in the well and barrier SL layers so that strain relaxation is effectively suppressed with increasing the SL layer thickness and high crystal quality can be expected. In this study, we fabricated the GaAs/GaAsP strain compensated SLs with the thickness up to 90-pair SL layers. Up to now, the electron spin polarization of 92 % and the quantum efficiency of 1.6 % were simultaneously achieved from 24-pair sample. In this study, to compare the time response performances with the SL thicknesses, the measurements were carried out for conventional and strain compensated SL PCs. We show the measurement results and discuss the physics.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY039

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMY040

Fabrication of Two Dimensional Nano-Scale Photocathode Arrays in Transparent Conductor for High Coherence Beam Generation

laser, cathode, photon, simulation

2645

T. Shibuya
TIT, Tokyo, Japan
N. Hayashizaki
RLNR, Tokyo, Japan
M. Yoshida
KEK, Ibaraki, Japan

Electron beam quality for particle source of diffractometer is mainly characterized by transverse and longitudinal coherent length, beam current density and so on. In order to improve a transverse coherent length, it is practically essential to minimize electrons emission area size as small as possible. However, the size of photoemission area is limited by focused laser beam size on the surface of cathode, and the scale is several microns. Aim to get definite overlap between the focused laser and emitters for effective irradiation, as well as to realize generation of nano-scale size electron beam, nano-scale photocathode arrays in transparent conductor are essential. Therefore, I propose to fabricate the nano-scale emission area in replace of limiting the focused laser size on the photocathode for achieving high coherence beam. The fabrication process of this novel nano-scale emitter configuration and its fundamental properties are presented in this paper.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY040

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMY041

Development of Mobile Neutron Sources Driven by X-Band Electron Linacs for Infrastructure Maintenance and Nuclear Security

neutron, target, linac, site

2648

Y. Seki, J.M. Bereder, M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan

We are developing a compact neutron source with a 3.95 MeV X-band (9.3 GHz) electron linac based X-ray source. The X-ray source, which included a tungsten target for bremsstrahlung, was originally fabricated for on-site nondestructive inspections for infrastructures such as bridges, expressways and tunnels. Attachment of a photo-neutron target to this X-ray source allows a new mobile neutron source. Main applications of this neutron source are on-site moisture detection in infrastructures, and nuclear materials measurement in fuel debris for decommissioning Fukushima nuclear power plants. Our approach also realizes a mobile X-ray/neutron hybrid source system in the future. The beryllium was employed as target material since it had especially small threshold energy for the photo neutron production. We have developed a 60-cm-cube target station by combining a beryllium block, a graphite reflector, a polyethylene moderator, a boric acid resin layer (neutron shied), and a lead layer (gamma-ray shield). This presentation will report a pilot experiment of neutron generation and discuss the results compared to a Monte Carlo simulation.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY041

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOR002

Orbit Stabilization for the HLS-II Storage Ring

storage-ring, quadrupole, feedback, alignment

2661

W. Xu, J.Y. Li, K. Xuan, H.Y. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

Hefei Light Source has successfully completed a major upgrade project, which greatly improves the light source performance. As one of the most important criteria, the stability of the beam orbit in the storage ring can greatly influence the overall performance of the light source. In this paper we present our efforts on stabilizing the beam orbit during the commissioning of the HLS-II storage ring. We optimized the performance of the power supplies of the ring corrector magnets. The target beam orbit is obtained by measuring the center of the quadrupole magnets using the beam-based alignment method. We also developed a multi-functional orbit feedback system to keep the beam moving on the golden orbit. With these measures, the beam orbit gets more stable than ten percent of the beam size at the light source points.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR002

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOR004

Fast Orbit Feedback System at the Pls-Ii Storage Ring

feedback, storage-ring, operation, timing

2667

S.-C. Kim, W.S. Cho, C. Kim, J.M. Kim, K.R. Kim, E.H. Lee, J. Lee, J.W. Lee, T.-Y. Lee, C.D. Park, G.S. Park, S. Shin, J.C. Yoon
PAL, Pohang, Kyungbuk, Republic of Korea

Funding: This work is supported by the Ministry of science, ICT and Future Planning, Korea.
The transverse position of the electron beam in the Pohang Light Source-II (PLS-II) is stabilized by the global orbit feedback system. Currently, 2 Hz slow orbit feedback (SOFB) system is operating, and 1 kHz fast orbit feedback (FOFB) system is installed recently. This FOFB system is consists of 96 electron beam position monitors (BPMs), 48 horizontal fast correctors, 48 vertical fast correctors and VME control system. We present the design and implementation of the FOFB system and its test result. Analysis through the simulation is presented and future improvement is discussed

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR004

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOR008

Development of a High Resolution Beam Position Monitor for NSRRC VUV/THz FEL

cavity, dipole, simulation, coupling

2680

P.J. Kung, K.C. Leou
NTHU, Hsinchu, Taiwan
W.K. Lau, A.P. Lee
NSRRC, Hsinchu, Taiwan

Beam position monitors (BPM) have been widely used on linear colliders and free electron lasers for beam-based alignment and feedback systems. A laser driven photo-injector system has been constructed in NSRRC. This injector has the capability to deliver short relativistic electron beam at high peak current for novel light source R&D. A 2.4 GHz BPM that can be used for high precision beam position measurement has been designed. The BPM were modified to separate frequency between the horizontal and vertical dipole signals, as well as a reduction of the monopole signal. The design has been simulated by CST. A prototype has been built for verification of theoretical predictions. Microwave bench measurement has been made to compare with the computer simulation results. The progress of our work will be presented in this paper.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR008

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOR015

Introduction to WPS System Designed to Measure the Change of Location for PAL-XFEL Girder

alignment, linear-collider, collider, electronics

2693

H. J. Choi, K.H. Gil, H.-S. Kang, H.-G. Lee, S.B. Lee, K.W. Seo
PAL, Pohang, Kyungbuk, Republic of Korea

To maintain stable electron beam parameters (Energy 10GeV, Charge 200pC, Bunch Length 60fs, Emittance X/Y 0.481um/0.256um), PAL-XFEL equipment should keep the alignment of accelerator (±100um) and undulator (±50um) constant. To ensure the precise measurement and alignment of PAL-XFEL, GPS-based surface geodetic network and the installation of a tunnel measurement network inside buildings was prepared and the fiducialization of major equipment was completed. After PAL-XFEL equipment is aligned, if the ground and buildings go through vertical changes during operation, tilt and misalignment of equipments (correct magnet, BPM, accelerator) will cause errors in the electron beam trajectory, which will lead to changes in the beam parameter. Hydrostatic Levelling System (HLS) was installed to measure vertical changes in buildings and the ground (sinking and uplifting) continuously and systematically, and Wire Position System (WPS) installed to measure changes in Girder. This paper introduces the operation principle, design concept, installation status, and operation status of WPS.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR015

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOR019

Development of CVD Diamond Detector for Beam Conditioning Monitor at the SuperKEKB Linac

detector, target, radiation, linac

2707

S. Kazama, T. Kamitani
KEK, Ibaraki, Japan
P. Bambade, V. Kubytskyi
LAL, Orsay, France

Positron beams in SuperKEKB will be produced from electromagnetic showers originating from the interaction between primary electron beams and a tungsten target. Since the emittance of primary beams is very small, the target is easy to be destroyed if focused beams are irradiated. In the SuperKEKB LINAC, a plate called spoiler is placed in the upstream of the target to enlarge the beam spot size. If the beam control is in a correct way, radioactive rays will be observed near both the spoiler and the target. However, if the beam control is not successful and primary beams are irradiated directly on the target, significant radiations are observed only near the target. If such a behavior is observed, primary beams must be stopped to protect the target. Since the number of electrons in a bunch is quite large(~10nC), the radiation dose is expected to be very high. Therefore, the radiation detector is required to have a high radiation-tolerance over a long period of time. Diamond has a high radiation tolerance due to its strong covalent bond, and we are now developing radiation detectors using diamond crystals. In this talk, current status including beam test measurements will be shown.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOR020

Beam Loss Estimation by Measurement of Secondarily Produced Photons under High Average-current Operations of Compact ERL in KEK

operation, detector, neutron, recirculation

2711

H. Matsumura, K. Haga, K. Hozumi, T. Miura, S. Nagaguro, T. Obina, T. Oyama, S. Sakanaka, A. Toyoda
KEK, Ibaraki, Japan
N. Yoshihara
Tokyo Nuclear Service Co. Ltd., Ibaraki, Japan

To increase the beam current in the Compact Energy Recovery Linac (cERL) at the High Energy Accelerator Research Organization (KEK), the beam loss must be reduced to less than 0.01% during the transportation of 20 MeV electrons in order to suppress the radiation dose outside the accelerator room. Beam loss locations were successfully identified using the gold activation method, and the beam loss rate was estimated by com-paring the measured dose rate with the simulated dose rate on the roof of the cERL room. Beam operation with beam current of 0.90 mA was achieved with a beam loss rate of less than 0.01%.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR020

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOR022

Residual Radiation Measurements at J-PARC MR Using the ASTROCAM 7000HS Newly Developed Radioactive Substance Visualization Camera

radiation, scattering, controls, site

2719

N. Ikeda, T. Sugano
MHI-MS, Kobe, Japan
K. Genba, M. Komeda, Y. Kuroda, D.M. Matsuura
MHI, Komaki-si, Japan
A. Harayama, T. Takahashi, S. Watanabe
ISAS/JAXA, Kanazawa, Japan
H. Nakamura, K. Niki, C. Ohmori, M.J. Shirakata
KEK, Ibaraki, Japan
S. Takeda
OIST, Onna-son, Okinawa, Japan

Mitsubishi Heavy Industries, Ltd. (MHI) released the ASTROCAM 7000HS, a radioactive substance visualization camera. The ASTROCAM 7000HS incorporates the technologies for the gamma-ray detector used for the ASTRO-H satellite, which MHI has been developing under entrustment from and together with scientists at the Institute of Space and Astronautical Science (ISAS) at the Japan Aerospace Exploration Agency (JAXA), and the design was modified for use on land to commercialize the product. MHI and Mitsubishi Heavy Industries Mechatronics Systems, Ltd. (MHI-MS) performed on-site residual radiation measurements at the 50 GeV Main Ring (MR) of the Japan Proton Accelerator Research Complex (J-PARC) under collaboration with the High Energy Accelerator Research Organization (KEK) and the Japan Atomic Energy Agency (JAEA) and succeeded visualization of radiation hot spots of the accelerator components. The outline of the ASTROCAM 7000HS, the measurement principle and the first measurement results at the J-PARC MR are described.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR022

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOR030

Gas Filled RF Resonator Hadron Beam Monitor for Intense Neutrino Beam Experiments

plasma, cavity, radiation, experiment

2733

K. Yonehara, A.V. Tollestrup, R.M. Zwaska
Fermilab, Batavia, Illinois, USA
R.J. Abrams, R.P. Johnson, G.M. Kazakevich
Muons, Inc, Illinois, USA
H.M. Dinkel
University of Missouri, Columbia, Columbia, Missouri, USA
B.T. Freemire
IIT, Chicago, Illinois, USA

Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359 and DOE HEP STTR Grant DE-SC0013795.
MW-class beam facilities are being considered all over the world to produce an intense neutrino beam for fundamental particle physics experiments. A radiation-robust beam monitor system is required to diagnose the primary and secondary beam qualities in high-radiation environments. We have proposed a novel gas-filled RF-resonator hadron beam monitor in which charged particles passing through the resonator produce ionized plasma that changes the permittivity of the gas. The sensitivity of the monitor has been evaluated in numerical simulation. A signal manipulation algorithm has been designed. A prototype system will be constructed and tested by using a proton beam at the MuCool Test Area at Fermilab.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR030

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOR034

Design and Evaluation of a Broad Band microTCA.4 Based Downconverter

LLRF, controls, radio-frequency, laser

2746

N. Gan, Y.L. Chi, R.L. Liu, X. Ma
IHEP, Beijing, People's Republic of China

Modern low-level RF (LLRF) control systems of particle accelerators are designed to achieve extremely precise field amplitude and phase regulation inside the accelerating cavities, the RF field signal is usually converted to an intermediate frequency (IF) before being sampled by ADC. As the down-conversion is an important procedure of the digital signal processing in LLRF system, designing a high performance and broad band downconverter compatible with various accelerators will be significant. In this paper, the design of a MicroTCA based downconverter is presented, the major design objective of this module is wider operating frequency range and more flexibility in application. Several performance evaluations on different frequency points of this module have been conducted and the module presents a good performance in the operating frequency range.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR034

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOR040

LLRF Development for PAL-XFEL

LLRF, operation, klystron, feedback

2761

J. Hu, W.H. Hwang, H.-S. Kang, H.-S. Lee, C.-K. Min, G. Mun
PAL, Pohang, Kyungbuk, Republic of Korea
J.H. Chang, J.S. Han, Y.S. Kim
RFPT, Gyeonggi-do, Republic of Korea
O.J. Kim, H.S. Lee
Mobiis Co., Ltd., Seoul, Republic of Korea

PAL-XFEL construction is completed. Now, beam commissioning is ongoing after RF conditioning. The LLRF and SSA systems installed and in normal operation are presented. Those structures, features, characteristics, and performances are described.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR040

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOR052

Emittance Measurements in Low Energy Storage Rings

emittance, antiproton, simulation, optics

2788

C.P. Welsch, J.R. Hunt, J. Resta-López
Cockcroft Institute, Warrington, Cheshire, United Kingdom
J.R. Hunt, J. Resta-López, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: Work supported by the EU under grant agreement 624854 and the STFC Cockcroft Institute Core Grant No. ST/G008248/1.
The development of the next generation of ultra-low energy antiproton and ion facilities requires precise information about the beam emittance to guarantee optimum performance. In the Extra-Low ENergy Antiproton storage ring (ELENA) the transverse emittances will be measured by scraping. However, this diagnostic measurements faces several challenges: non-zero dispersion and systematic errors due to diffusion processes, such as intra-beam scattering, and the speed of the scraper with respect to the beam revolution frequency. In addition, the beam distribution will likely be non-Gaussian. Here, we present algorithms to efficiently address the emittance reconstruction in presence of the above effects, and present simulation results for the case of ELENA. We also discuss the feasibility of using alternative non-invasive techniques for profile and emittance measurements.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR052

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOR058

Preliminary Study for the HLS Variable Pulse Length Storage Ring by Two Harmonic Cavities

cavity, beam-loading, storage-ring, synchrotron

2802

T. Zhang, W. Li, L. Shang, L. Wang, C.-F. Wu
USTC/NSRL, Hefei, Anhui, People's Republic of China

The 4th harmonic cavity is successfully used in HLS II to increase the beam lifetime and suppress the beam instability now. At the future, a scheme of the two higher harmonic cavities may be applied in Hefei light source for a variable electron pulse length storage ring (HLS VSR). With optimal RF system parameters, 45 ps long bunches and 6 ps short bunches may be stored simultaneously in the HLS storage ring. The ratio of the bunch number for 45 ps to the one for 6 ps is 1:2. Particle tracking calculations are performed to simulate the longitudinal phase space of the new system and to track the process of shortening bunches with Elegant Software. Moreover, a tracking simulation code for RF systems is developed in MALAB to study transient beam loading which affects bunch length, phase stability, and longitudinal muti-bunch oscillation for different fill patterns. In the end, the preliminary design of the two harmonic cavities for longitudinal bunch focusing is given.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR058

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOR059

Calculation for the Radiation Dose in Storage Ring Hall based on Monte Carlo Method

radiation, storage-ring, neutron, vacuum

2805

S. Huang, T.L. He, S.C. Zhang, T. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

Radiation dose assessment in synchrotron radiation facility is challenging due to the complexity and uncertainties of radiation source terms induced by high energy particle accelerator. Hefei light source (HLS) is the first dedicated synchrotron radiation light source in China. Radiation dose assessment for users at HLS Beam lines is highly concerned. This study presents the method calculating the radiation dose in storage ring hall under normal operation state, the simplified Monte Carlo calculation model was introduced in detail. We obtained the results of radiation dose distribution in HLS storage ring hall with using MCNP, which are in the same order of magnitude with the experimental results. It indicates that the method can be used to calculate the radiation dose level in storage ring hall, and it has certain guiding significance for the radiation protection.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR059

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOW008

Specific Operation Modes at the Metrology Light Source

operation, emittance, radiation, cavity

2829

J. Feikes, P. Goslawski, J. Li, M. Ries, M. Ruprecht, G. Wüstefeld
HZB, Berlin, Germany
A. Hoehl
PTB, Berlin, Germany

The high flexibility of the Metrology Light Source (MLS) allows application of various nonstandard user modes adapted to the specific needs of their users. We report on some of them including a mode for division of the revolution frequency for the user signal and a mode with an adjustable photon pulse delay on the few ps scale.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW008

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOW013

Coherent Harmonic Generation in the Presence of Synchronized RF Phase Modulation at DELTA

resonance, synchrotron, laser, radiation

2847

M.A. Jebramcik, F.H. Bahnsen, M. Bolsinger, S. Hilbrich, M. Höner, S. Khan, C. Mai, A. Meyer auf der Heide, R. Molo, G. Shayeganrad, P. Ungelenk
DELTA, Dortmund, Germany

Funding: Work supported by the BMBF (05K13PEC), DFG (INST 212/236-1) and the Stiftung Mercator (Pr-2014-0047).
At the 1.5-GeV synchrotron light source DELTA operated by the TU Dortmund University, ultrashort coherent pulses in the VUV and THz regime are generated via coherent harmonic generation (CHG). The intensity of the light depends strongly on the quality of the laser-electron interaction and therefore on the energy spread and density of the electron bunches. In 2014, a significant increase of the CHG intensity was observed by phase-modulating the RF cavity voltage, which is routinely used to prolong the beam lifetime. RF phase modulation can generate multiple stable regimes (islands) in longitudinal phase space when run near an integer multiple of the synchrotron frequency resulting in a modulation of the electron density and energy spread. A numerical simulation supporting the experimental observations is presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW013

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOW014

Spectral Studies of Ultrashort and Coherent Radiation Pulses at the DELTA Storage Ring

laser, radiation, undulator, bunching

2851

S. Khan, F.H. Bahnsen, M. Bolsinger, F. Götz, S. Hilbrich, M.A. Jebramcik, N.M. Lockmann, C. Mai, A. Meyer auf der Heide, R. Niemczyk, G. Shayeganrad, P. Ungelenk, D. Zimmermann
DELTA, Dortmund, Germany

Funding: Work supported by the BMBF (05K13PEC, 05K13PE3), the DFG (INST 212/236-1 FUGG), the Stiftung Mercator (Pr-2014-0047) and the state of NRW.
At the 1.5-GeV synchrotron light source DELTA operated by the TU Dortmund University, ultrashort and coherent radiation pulses in the VUV and THz regime are routinely generated by the interaction of electron bunches with 45-fs laser pulses. A laser-induced modulation of the electron energy is converted into a density modulation (microbunching) by a magnetic chicane, giving rise to coherent emission at harmonics of the initial laser wavelength (coherent harmonic generation, CHG). As a first step towards active control of the shape and spectrum of CHG pulses, spectral studies were performed under variation of the chicane strength and the laser properties. The spectral phase of the laser pulses was controlled by tuning the compressor of the laser amplifier and was monitored using FROG (frequency-resolved optical gating). In this paper, monochromator scans as well as single-shot spectrograms of the CHG radiation are presented and compared to simulations of the laser-electron interaction and microbunching process. In addition, other results from the short-pulse facility as well as a future upgrade employing the echo-enabled harmonic generation (EEHG) scheme will be outlined.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW014

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOW031

Performance of the Vacuum System for the Solaris 1.5 GeV Electron Storage Ring

storage-ring, vacuum, injection, synchrotron

2898

A.M. Marendziak, C.J. Bocchetta, P.B. Borowiec, P. Bulira, L.J. Dudek, P.P. Goryl, K. Karaś, A. Kisiel, W.T. Kitka, M.P. Kopec, M. Madura, R. Nietubyć, M.P. Nowak, M.J. Stankiewicz, A.I. Wawrzyniak, K. Wawrzyniak, J.J. Wiechecki, J. Wikłacz, M. Zając, Z. Zbylut, L. Żytniak
Solaris National Synchrotron Radiation Centre, Jagiellonian University, Kraków, Poland

Solaris is a third generation light source recently constructed at the Jagiellonian University in Kraków, Poland. The machine was designed by the team at the MAX IV Laboratory. A replica of the 1.5 GeV MAX IV storage ring with a 96 m circumference was successfully built at Solaris and now the facility is in its 3rd phase of commissioning. The average pressure in the storage ring was 1.2·10^-10 mbar before beam commissioning and increases to 1.2·10-8 mbar with 511 mA of stored beam current for electron energy of 524 MeV. With 10 A·h accumulated beam dose, beam cleaning has permitted an average pressure of 3·10-10 mbar/mA. In this paper the result of vacuum performance from beam cleaning and the beam lifetime will be presented. Moreover vacuum maintenance procedures will be reported.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW031

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOW032

Impact of the DBA Blocks Alignment on the Beam Dynamics of the Storage Ring in Solaris

storage-ring, alignment, synchrotron, vacuum

2902

J.J. Wiechecki, C.J. Bocchetta, M. Boruchowski, P. Król, A.I. Wawrzyniak
Solaris, Kraków, Poland
K. Karaś, A.M. Marendziak, R. Nietubyć
Solaris National Synchrotron Radiation Centre, Jagiellonian University, Kraków, Poland

Installation of the Solaris synchrotron has been accomplished at the beginning of the 2015. Although the machine is a replica of the 1.5 GeV ring at MAX IV in Sweden, the entire group responsible for the installation, was facing numerous problems during the entire installation period. One of the most critical issues that are responsible for the proper functionality of the machine is the survey of the machine. An appropriate alignment of the components in accordance to each other as also to the building, provides a good quality of the beam so extensively desired by the beamline's users. This paper presents the results of the alignment in the 1.5 GeV ring, describes possible critical sectors of the ring that might influence the accuracy of the measurements and juxtapose the results with the values gained during the operational phase of the synchrotron. This comparison enables the identification of the beam losses and extension of the lifetime of the electron beam.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW032

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOW034

Emittance Diagnostics at the Max Iv 3 Gev Storage Ring

dipole, radiation, emittance, diagnostics

2908

J. Breunlin, Å. Andersson
MAX IV Laboratory, Lund University, Lund, Sweden

With the MAX IV project in Lund, Sweden an ultralow emittance storage ring light source is going into user operation in 2016. Due to its multibend achromat lattice design the 3 GeV storage ring reaches a horizontal emittance lower than 330 pm rad. Emittance diagnostic will involve two diagnostic beamlines to image the electron beam with infrared and ultraviolet synchrotron radiation from bending dipoles. Placed in locations of different optic functions the beamlines will provide experimental access to both horizontal and vertical emittance and to beam energy spread. Since bunch lengthening with harmonic cavities is essential for machine performance, time resolved measurements with synchrotron radiation for individual longitudinal bunch distributions are of special interest as well.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW034

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOW042

Properties of Synchrotron Radiation from Segmented Undulators based on a Wigner Distribution Function

undulator, brilliance, radiation, photon

2933

H.W. Luo, C.H. Lee
NTHU, Hsinchu, Taiwan
T.Y. Chung, C.-S. Hwang
NSRRC, Hsinchu, Taiwan

Three long straight sections with a double mini-βy lattice were designed in Taiwan Photon Source. For the purpose to understand whether the brilliance can be enhanced or not when two collinear undulators were installed in the double mini-βy. Therefore, the Wigner distribution function (WDF) is developed to calculate the brilliance in the double mini-βy lattice that is a natural way to describe a synchrotron radiation source. Herein, the brilliance is thereby calculable without a Gaussian approximation used in a conventional manner. Some important optical properties such as the degree of coherence can be directly calculated with this method. We use it as an example to investigate the properties of radiation from a segmented undulator.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW042

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOW043

Accelerator Based Light Source Projects of Turkey

FEL, undulator, linac, radiation

2936

A.A. Aksoy, Ö. Karslı, C. Kaya
Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
B. Ketenoğlu, O. Yavaş
Ankara University, Faculty of Engineering, Tandogan, Ankara, Turkey
Z. Nergiz
Nigde University, Nigde, Turkey

Three light source project is ongoing in Turkey within the frame of Turkish Accelerator Center (TAC) Project which has been supported by Ministry of Development since 2006. As a first facility of TAC, 3-250 μ mm IR-FEL facility (TARLA) based on superconducting accelerator with an energy of maximum 40 MeV is under construction at Institute of Accelerator Technologies of Ankara University. In addition to TARLA, Conceptual/Technical Design Report of a third generation synchrotron radiation facility based on 3 GeV, and a fourth generation FEL facility based 1-6 GeV is being prepared for the next steps of TAC. Therewithal a proton accelerator facility with up 2 GeV and an electron-positron collider as a super charm factory are proposed within the frame of TAC project. In this presentation, current status of TARLA project and main goals, road map of Turkish Light Sources will be explained.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW043

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOW055

Bayesian Optimization of FEL Performance at LCLS

FEL, controls, interface, laser

2972

M.W. McIntire, T.M. Cope, D.F. Ratner
SLAC, Menlo Park, California, USA
S. Ermon
Stanford University, Stanford, California, USA

Funding: Research is supported by the U.S. Department of Energy under Contract No. DE-AC02-76SF00515.
The LCLS free-electron laser at SLAC is tuned via a huge number of parameters such as energy and magnet settings. Much of this tuning, including quadrupole magnet settings, is typically done by hand by the LCLS operators. In this paper we introduce an automated tuning system using Bayesian optimization, and describe its application to the optimization of noisy objectives such as FEL performance. We demonstrate with preliminary results from our implementation at LCLS that this system can improve both the speed of tuning procedures as well as the quality of the resulting solution.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW055

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOY009

Simulation Study of Emittance Growth from Coulomb Explosion in a Charge Separator System After Stripping

emittance, space-charge, simulation, ion

3005

M. Droba, O. Meusel, U. Ratzinger
IAP, Frankfurt am Main, Germany

Funding: BMBF-05P15RFRBA
A computer 3D particle-in-cell (PIC) simulation is used to examine the emittance growth of an intense heavy ion beam after a charge stripper. Multi-species dynamics of the bunched uranium beam with various charge states and including compensation electrons will be presented. The rms-emittance growth shows different behaviour in the horizontal, vertical and longitudinal planes, dependent on initial conditions, like a bunch size, beam current and phase space ellipse orientation. An optimization of initial parameters is therefore crucial for a successful and efficient post-acceleration. The role of the separation system and of co-moving electrons will be discussed for the example of the GSI-Unilac.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY009

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOY010

Bunch Compression at the Recirculation Loop of the Compact ERL

simulation, linac, optics, acceleration

3008

M. Shimada, K. Harada, Y. Honda, T. Miyajima, N. Nakamura, T. Obina, R. Takai, A. Ueda
KEK, Ibaraki, Japan

The compact Energy Recovery Linac (cERL) has been operated as a test facility for the future light-source since 2013. One of the targets of the beam commissioning of this winter is demonstration of bunch compression. The bunch has energy chirp in longitudinal direction by off crest acceleration and the bunch length is compressed in non-isochronous arc section. The short electron bunch is spread in the return arc to suppress the energy spread at the main beam dump. Four sextupole magnets were installed in two arcs in November 2015 to correct the squared term induced by RF curvature. The best position was determined by the beam tracking by elegant including Coherent Synchrotron Radiation (CSR) wake. The bunch length is measured by OTR in the south straight section just after the first arc. We present the demonstration of the bunch compression in this report.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY010

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOY015

Longitudinal Bram Dynamics at Rf-Compressor

gun, space-charge, simulation, brightness

3011

A.V. Andrianov
BINP SB RAS, Novosibirsk, Russia

Nowadays the usage of charged particle beams for study of nature became widespread. Modern experiments are require particle beams with duration around hundreds femtosecond. Relatively simple and cheap method of production such pulses is using RF-gun with photocathode and then the special insertion device which compress the beam. The paper described the RF-compressor for the electron beam. In result of work was obtained a device configuration. Electromagnetic field configuration and distribution were simulated for the configuration. Beam dynamics was computed in this field distribution. Incoming beam parameters are following: beam length is 1-5ps, beam charge is 0.1-2pC and energy is 3MeV. Output beam duration was compressed to less than 150fs. Influence of RF-compressor at beam parameters was estimated.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY015

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOY018

Study on Electron Beam Transverse Emittance at the Linac-based THz Laboratory in Thailand

emittance, quadrupole, simulation, linac

3017

K. Kosaentor
IST, Chiang Mai, Thailand
S. Rimjaem
Chiang Mai University, Chiang Mai, Thailand

This research focuses on simulation of transverse emittance of electron beams, which are produced from a thermionic RF-gun at the Plasma and Beam Physics (PBP) Research Facility, Chiang Mai University (CMU). The RF-gun is used to together with an alpha magnet for serving as the electron injector system for the PBP linac-based THz source. The quadrupole scan technique is utilized to measure the transverse beam emittance at the entrance of the alpha magnet. The experimental setup consists of quadrupole magnets with a maximum gradient of 7.01 T/m, a drift tube, and a movable fluorescent screen station. Beam dynamic simulations by using the computer codes PARMELA and ELEGANTare performed to track electrons from the cathode to the experimental station. In this contribution, the emittance values from simulations including the space charge effects will be reported.
This work has been supported by the CMU Junior Research Fellowship Program, Department of Physics and Material Science, Faculty of science, Chiang Mai University.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY018

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOY019

Beam Optimization Study for an X-ray FEL Oscillator at the LCLS-II

flattop, emittance, FEL, linac

3020

W. Qin, S. Huang, K.X. Liu
PKU, Beijing, People's Republic of China
K.L.F. Bane, Y. Ding, Z. Huang, T.J. Maxwell
SLAC, Menlo Park, California, USA
K.-J. Kim, R.R. Lindberg
ANL, Argonne, Ilinois, USA

The 4 GeV LCLS-II superconducting linac with high repetition beam rate enables the possibility to drive an X-Ray FEL oscillator at harmonic frequencies *. Compared to the regular LCLS-II machine setup, the oscillator mode requires a much longer bunch length with a relatively lower current. Also a flat longitudinal phase space distribution is critical to maintain the FEL gain since the X-ray cavity has extremely narrow bandwidth. In this paper, we study the longitudinal phase space optimization including shaping the initial beam from the injector and optimizing the bunch compressor and dechirper parameters. We obtain a bunch with a flat energy chirp over 400 fs in the core part with current above 100 A. The optimization was based on LiTrack and Elegant simulations using LCLS-II beam parameters.
* T. J. Maxwell et al., Feasibility study for an X-ray FEL oscillator at the LCLS-II, IPAC15, TUPMA028.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOY022

Light Optics for Optical Stochastic Cooling

undulator, radiation, kicker, pick-up

3028

M.B. Andorf, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
V.A. Lebedev, P. Piot, J. Ruan
Fermilab, Batavia, Illinois, USA

Funding: This work was supported by the US DOE under contract DE-SC0013761 with Northern Illinois University. Fermilab is operated by the Fermi Research Alliance LLC under US DOE contract DE-AC02-07CH11359.
In Optical Stochastic Cooling (OSC) radiation generated by a particle in a "pickup" undulator is amplified and transported to a downstream "kicker" undulator where it interacts with the same particle which radiated it. Fermilab plans to carry out both passive (no optical amplifier) and active (optical amplifier) tests of OSC at the Integrable Optics Test Accelerator (IOTA) currently in construction*. The performace of the optical system is analyzed with simulations in Synchrotron Radiation Workshop (SRW) accounting for the specific temporal and spectral properties of undulator radiation and being augmented to include dispersion of lens material.
* V. Lebedev, et al., Proc. COOL'15 (in press, 2015).

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY022

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOY023

Beam Dynamics Studies for Coherent Electron Cooling Experiment

emittance, linac, SRF, cavity

3032

Y.H. Wu, D. Kayran, V. Litvinenko, I. Pinayev
BNL, Upton, Long Island, New York, USA
V. Litvinenko
Stony Brook University, Stony Brook, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Coherent electron Cooling (CeC)* is a proposed advanced beam cooling method that has the potential to reduce the ion beam emittance in significantly shorter time compared to existing cooling methods. The newly constructed linear electron accelerator for the CeC experiment can generate electron beams with the required beam parameters for effective cooling. In this paper, we show simulation studies for the CEC linac by using the PARMELA** and ELEGANT*** beam dynamics tracking codes.
* V.N.Litvinenko and Y.S.Derbenev, PRL 102, 114801 (2009)
** Lloyd M.Young, Parmela manual, Los Alamos National Laboratory
*** M. Borland, Elegant, Argonne National Laboratory (2000)

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY023

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOY024

Beam Dynamics Simulations of the Thomx Linac

emittance, gun, solenoid, laser

3036

L. Garolfi, C. Bruni, M. El Khaldi, P. Lepercq, C. Vallerand
LAL, Orsay, France
N. Faure
PMB-ALCEN, PEYNIER, France

ThomX Compton light source is designed to maximise the average X-ray flux providing a compact and tunable machine which can operate in hospitals or in museums. These constraints impose the choice of a high collision rate which is based on S-band Linac whose energy is 50-70 MeV combined to an electron storage ring. As most of the performances of the electron beam at the interaction point depend on the beam quality at the ring entrance, the linear accelerator must be carefully designed and especially the photo-injector. Simulations have been carried out in order to optimise the emittance for the ring entrance. Indeed, for a bunch charge of 1 nC, space charge effects usually dominate the total beam emittance. The latter can be minimized at the end of the Linac by means of emittance compensation. The best configuration across all the parameters will be presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY024

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOY025

High Power RF Generation From a W-Band Corrugated Structure Excited by a Train of Electron Bunches

wakefield, experiment, simulation, acceleration

3040

D. Wang, C.-X. Tang
TUB, Beijing, People's Republic of China
S.P. Antipov, C.-J. Jing, J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA
M.E. Conde, D.S. Doran, W. Gai, G. Ha, G. Ha, W. Liu, J.G. Power, E.E. Wisniewski
ANL, Argonne, Illinois, USA
V.A. Dolgashev
SLAC, Menlo Park, California, USA

We report on the generation of multi-megawatt peak RF power at 91textGHz, using an ultrarelativistic electron bunch train to excite electromagnetic fields in a high-impedance metallic corrugated structure. This device can be used as a power source for high gradient acceleration of electrons. To achieve precise control of the wakefield phase, a long range wakefield interferometry method was developed in which the RF energy due to the interference of the wakefields from two bunches was measured as a function of the bunch separation.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY025

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOY026

Simulation and Measurement of the Beam Breakup Instability in a W-band Corrugated Structure

wakefield, dipole, simulation, radiation

3044

D. Wang, C.-X. Tang
TUB, Beijing, People's Republic of China
S.P. Antipov, C.-J. Jing, J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA
M.E. Conde, D.S. Doran, W. Gai, G. Ha, W. Liu, J.G. Power, E.E. Wisniewski
ANL, Argonne, Illinois, USA

The corrugated wakefield structure has wide application in electron beam energy manipulation and high frequency RF radiation generation. The transverse wakefield which cause beam breakup (BBU) instability is excited when the drive beam is not perfectly centered through the structure. Here we report on the numerical and experimental investigation of the BBU effect in a W-band corrugated structure, for both cases of short range wakefield and long range wakefield. In the numerical part we develop a point to point (P2P) code that allows rapid and efficiency simulations of the beam dynamics effect by wakefield, which is based on the the particle-wake function coupled dynamics equation of motion. And the experimental measurements of BBU effect are found to be in good agreement with the simulations.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY026

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOY028

Laser Heater System Test at PAL-XFEL ITF

laser, undulator, FEL, bunching

3048

J. H. Lee
POSTECH, Pohang, Kyungbuk, Republic of Korea
J.H. Han, J.H. Hong, C.H. Kim, I.S. Ko, S.J. Lee
PAL, Pohang, Kyungbuk, Republic of Korea

Coherent x-ray photons are generated by a free electron laser (FEL). In PAL-XFEL, a photon beam with a 0.1 nm wavelength is generated from an electron bunch based on self-amplified spontaneous emission (SASE). An electron bunch with an uncorrelated energy spread in a level of 3 keV, which is generated from the photocathode RF gun, may be sensitive to longitudinal micro-bunching instability. The energy spread of an electron bunch can be increased to suppress the instability by Landau damping. In order to control the uncorrelated energy spread, a laser heater system, which has a chicane with four dipoles chicane and a 0.5 m long undulator, was installed in the injector test facility (ITF) of PAL. In this paper, we introduce the parameters of the laser heater and heating effect on the electron bunch.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY028

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOY033

Space Charge Compensation in Low Energy Beam Lines

space-charge, simulation, proton, solenoid

3055

F. Gérardin, N. Chauvin, D. Uriot
CEA/IRFU, Gif-sur-Yvette, France
M.A. Baylac, D. Bondoux, F. Bouly
LPSC, Grenoble Cedex, France
A. Chancé, O. Napoly, N. Pichoff
CEA/DSM/IRFU, France

The dynamics of a high intensity beam with low energy is governed by its space-charge forces which may be responsible of emittance growth and halo formation due to their non-linearity. In a low energy beam transport (LEBT) line of a linear accelerator, the propagation of a charged beam with low energy causes the production of secondary particles created by the interaction between the beam and the background gas present in the accelerator tube. This phenomenon called space-charge compensation is difficult to characterize analitically. In order to obtain some quantitative to characterize the space-charge compensation (or neutralization), numerical simulations using a 3D PIC code have been implemented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY033

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOY035

Free Electron Laser Simulation Tool Based on FDTD/PIC in the Lorentz Boosted Frame

FEL, simulation, undulator, radiation

3061

A. Yahaghi, A. Fallahi, F.X. Kärtner
CFEL, Hamburg, Germany
F.X. Kärtner
MIT, Cambridge, Massachusetts, USA

Funding: Alexander von Humboldt-Foundation European Research Council(ERC)
Free Electron Lasers (FELs) are promising sources capable of generating electromagnetic waves in the whole spectrum. Therefore, it is crucial and additionally very useful to develop sophisticated though complete simulation tools. This goal is mainly motivated by our research focus on the development of compact X-ray sources based on radiation in optical undulators. The currently existing softwares are usually written to tackle special cases with particular approximations, such as 1D FEL theory, steady state, slow wave and forward wave approximation, wiggler-averaged electron motion and slices approximation. Many of the above approximations are hardly valid when sub-femtosecond bunches interact with intense optical lasers. The presented software aims the analysis of the FEL interaction without considering any of the above approximations. The developed tool apparently suffers from long computation times but offers a more accurate picture on the radiation process. In order to overcome the problem of multidimensionality, we exploit Lorentz boosted coordinate system and implement Finite Difference Time Domain (FDTD) method combined with Particle in Cell (PIC) simulation in this frame.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY035

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOY037

Optimization of THz Radiation Pulses at FLUTE

radiation, simulation, gun, linac

3067

M. Yan, A.-S. Müller, M.J. Nasse, M. Schuh, M. Schwarz
KIT, Karlsruhe, Germany

The accelerator test facility FLUTE (Ferninfrarot Linac Und Test Experiment) will allow research and development in electron accelerator technology as well as photon science. Electron bunches of durations in the femtosecond range will be provided to generate intense THz radiation. Start-to-end simulation of the accelerator has been performed with the bunch length as the optimization objective. Based on the resulting charge distribution the expected THz field properties can be calculated. In this paper we combine the two tools and present first results.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY037

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOY039

GIOTTO: A Genetic Code for Demanding Beam-dynamics Optimizations

software, space-charge, gun, interface

3073

A. Bacci
Istituto Nazionale di Fisica Nucleare, Milano, Italy
V. Petrillo
Universita' degli Studi di Milano, Milano, Italy
M. Rossetti Conti
Universita' degli Studi di Milano & INFN, Milano, Italy

GIOTTO is a software based on a Genetic Algorithm (GA). Its development started in 2007 with a work published on NIMB (263, 2007, 488-496) and presented at PAC07 (THPAN031). When the parameters, defining an acceleration machine beam line, are strongly correlated in nonlinear way, the GAs are a powerful tool to coup with these difficulties. These conditions are typically generated by space-charge, as in the high brightness e-beam photo-injectors or when the Velocity Bunching compression technique (VB) is used. The power of GIOTTO is the adaptability to different cases, given by its own structure that permits to drive different external codes in series, the possibility to define a user dependent multi objective fitness function and function constraints on the beam dynamics, as well as the possibility to turn off the genetic optimization to perform statistical analysis (machine jitters). Up today it has been used in Thomson/Compton sources, ultra-short e-bunches generation by VB, focusing channel and dog-leg lines optimizations.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY039

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOY056

Beam-beam Simulations with Realistic Crab Crossing for the eRhic Ring-Ring Electron Beam

proton, cavity, luminosity, hadron

3123

C. Montag
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The 15mrad beam crossing angle in the eRHIC ring-ring interaction region requires crab crossing of the 250GeV proton beam to restore the luminosity. Since the product of the RF voltage and the RF frequency of the crab cavities is constant for a given crossing angle, higher frequencies are preferred in order to limit the require voltage. However, the 20cm RMS proton bunch length provides an upper limit of the useable frequencies due to the significant curvature of the RF waveform over this bunch length. To study the effectof realistic crab cavities with a finite wavelength on electron beam-beamdynamics and to determine the potential need for higher harmonic crab cavities to linearize the kick a simulation code has been developed.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY056

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOY057

The 2015 eRHIC Ring-Ring Design

proton, luminosity, polarization, emittance

3126

C. Montag, E.C. Aschenauer, J. Beebe-Wang, J.S. Berg, M. Blaskiewicz, J.M. Brennan, A.V. Fedotov, W. Fischer, V. Litvinenko, R.B. Palmer, B. Parker, S. Peggs, V. Ptitsyn, V.H. Ranjbar, S. Tepikian, D. Trbojevic, F.J. Willeke
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
To reduce the technical risk of the future electron-ion collider eRHIC currently under study at BNL, the ring-ring scheme has been revisited over the summer of 2015. The goal of this study was a design that covers the full center-of-mass energy range from 32 to 141 GeV with an initial luminosity around 10³³ cm^-2 sec^-1, upgradeable to 10³⁴ cm^-2 sec^-1 later on. In this presentation the baseline design will be presented, and future upgrades will be discussed.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY057

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOY058

Design of the 2015 Erhic Ring-Ring Interaction Region

hadron, proton, neutron, quadrupole

3129

C. Montag, B. Parker
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The 2015 ring-ring design study of the electron-ion collider eRHIC aims at an e-p luminosity around 10³³ cm^-2 sec^-1 over a center-of-mass energy range from 32 to 141 GeV, while at the same time providing the required detector geometry and acceptance for the proposed physics program. The latest interaction region design will be presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY058

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THOAA03

MicroTCA.4 based Single Cavity Regulation including Piezo Controls

cavity, controls, operation, feedback

3152

K.P. Przygoda, H. Schlarb, Ch. Schmidt
DESY, Hamburg, Germany
P. Echevarria
HZB, Berlin, Germany
R. Rybaniec
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland

We want to summarize the single cavity regulation with MTCA.4 electronics. Presented solution is based on the one MTCA.4 crate integrating both RF field control and piezo tuner control systems. The RF field control electronics consists of RTM for cavity probes sensing and high voltage power source driving, AMC for fast data processing and digital feedback operation. The piezo control system has been setup with high voltage RTM Piezo driver and low cost AMC based FMC carrier. The communication between both control systems is performed using low latency link over the AMC backplane with data throughput up to the 3.125 Gbps. First results from CW operation of the RF field controller and the cavity active resonance control with the piezo tuners are demonstrated and briefly discussed.

Slides THOAA03 [2.693 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THOAA03

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THOAB02

Concept of RF Linac for Intra-pulse Multi-energy Scan

klystron, linac, experiment, gun

3180

A.K. Krasnykh, J. Neilson, A.D. Yeremian
SLAC, Menlo Park, California, USA

Funding: Work supported in part by US Department of Energy under contract DE-AC02-76SF00515
A material discrimination based on X-Ray systems is typically achieved by alternating photon pulses of two different energies. A new approach relies on the ability to generate X-ray pulses with an end-point energy that varies in a controlled fashion during the duration of the pulse. An intra-pulse multi-energy X-ray beam device will greatly enhance current cargo screening capabilities. This method originally was described in the AS&E patents*. This paper addresses a linac concept for the proposed scan and describes some proof of concept experiments carried out at SLAC.
* A. Arodzero et al., 'System and methods for intra-pulse multi-energy and adaptive multi-energy X-ray cargo inspection', US Patent 8,457, 274, 2013

Slides THOAB02 [1.776 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THOAB02

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THOAB03

Ultrafast Electron Microscopy using 100 Femtosecond Relativistic-Energy Electron Beam

emittance, gun, brightness, laser

3183

J. Yang, K. Kan, K. Tanimura, Y. Yoshida
ISIR, Osaka, Japan
J. Urakawa
KEK, Ibaraki, Japan

An ultrafast detection technique on 100 fs time scales over sub-nanometer (even atomic) spatial dimensions has long been a goal for the scientists to reveal and understand the ultrafast structural-change induced dynamics in materials. In this paper, the generation of femtosecond electron pulses using the RF gun and the first prototype of femtosecond time-resolved relativistic-energy ultrafast electron microscopy (UEM) are reported. Finally, both relativistic-energy electron diffraction and image measurements in the UEM prototype are presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THOAB03

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMB004

Improving Energy Spread and Stability of a Recirculating Few-turn Linac

linac, recirculation, synchrotron, experiment

3222

F. Hug
IKP, Mainz, Germany
M. Arnold, T. Kürzeder, N. Pietralla
TU Darmstadt, Darmstadt, Germany
R.G. Eichhorn
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Supported by the DFG through CRC 634, RTG 2128 and PRISMA cluster of excellence
A non-isochronous recirculation scheme which helps cancelling out errors coming from the RF-jitters in a recirculating linac will be presented. Non-isochronous recirculation is the common operation mode for synchrotrons or microtrons. In such a scheme the recirculation arcs provide a non-zero longitudinal dispersion, while the particle bunches are accelerated at a certain phase off-crest with respect to the maximum of the accelerating field. In few-turn linacs and microtrons such beam dynamics can be used to reduce the energy spread. To do so the longitudinal phase advance needs to be set to a half-integer number of oscillations in phase space. Then errors from linac RF-systems cancel out and the energy spread remains closely to the value at injection. In addition to the improved energy spread the beam stability of few-turn recirculators can be increased as well using such a system. We will present operational experience with the non-isochronous recirculation system of the twice recirculating superconducting accelerator S-DALINAC operated at TU Darmstadt including beam-dynamics calculations and measurements of the energy spread.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB004

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMB008

Compensation of Steerer Crosstalk between FLASH1 and FLASH2

betatron, laser, FEL, free-electron-laser

3237

F. Christie, B. Schmidt, M. Vogt
DESY, Hamburg, Germany

The free-electron laser in Hamburg (FLASH) is a user facility delivering soft X-ray radiation. Starting from 2014, a second beam line for user operation, FLASH2, has been commissioned. It uses the same accelerating modules as the initial FLASH beam line (FLASH1) and the beam is deflected into a separate beam line downstream the linac. In the region, where the FLASH2 beam is extracted, both beam lines are close, the angle in between is 6.5 degrees. It has been observed, that steering dipoles in the extraction area, have an influence on both beam lines. Thus steering the orbit in one beam line, perturbs the orbit in the other beam line. This perturbation can significantly degrade the SASE energy in the other beam line. We have found a solution to this problem based the combination of local orbit bumps. The crosstalk from one steerer is corrected using additional steerers in the other beam line. This concept has already been tested at FLASH and has proven to work sufficiently well.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB008

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMB010

Dogleg Design for the SINBAD Linac

acceleration, dipole, linac, emittance

3244

J. Zhu, R.W. Aßmann, U. Dorda, B. Marchetti
DESY, Hamburg, Germany
R. Rossmanith
KIT, Karlsruhe, Germany

The SINBAD facility (Short and INnovative Bunches and Accelerators at DESY) is foreseen to provide sub-fs to tens of fs electron bunches for the R&D of novel acceleration concepts and applications, e.g. Laser Wake-Field Acceleration (LWFA), Dielectric Laser Acceleration (DLA) and medical imaging. We present the design study of the dogleg at the SINBAD linac, which is capable of delivering ultra-short bunches to the second beamline. The longitudinal dispersion of the dogleg can be finely tuned so that it can either transport the ultra-short bunch produced upstream by velocity bunching, or compress the incoming long bunch. The achievable beam parameters are investigated by start-to-end simulations.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB010

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMB013

Proposal of 6 GeV Energy Recovery Linac Hybrid Machine

positron, linac, cavity, undulator

3254

M. Shimada, K. Yokoya
KEK, Ibaraki, Japan
R. Hajima
JAEA, Ibaraki-ken, Japan
M. Tecimer
University of Hawaii at Manoa, Honolulu, USA

We proposed 6 GeV Energy Recovery Linac (ERL) as an intense gamma-ray source for the polarized positron source of International Linear Collider (ILC)*. In this scheme, Coherent Synchrotron Radiation from quasi-CW 6 GeV electron beam is stacked in optical cavity at middle infrared region, and it is used for inverse Compton scattering to generate 10 MeV polarized gamma-ray. The same 6 GeV superconducting linac accelerates both the electron and positron beams up to 5 GeV for injection to the dumping ring. Furthermore, it is available for X-ray light source by adding another recirculation loop. It can be expected as a diffraction limit light source at 10 keV, and the target of the brilliance is 10^22-23 ph/s/mm²/mrad²/b.w.0.1%.
* M. Shimada, Proceedings of IPAC'13

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB013

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMB021

Design of the Magnets of the Far-Infrared FEL Project at NSRL

dipole, quadrupole, simulation, FEL

3269

T.L. He, H. Xu, W. Xu, S.C. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: National Natural Science Foundation of China (10875118); National Natural Science Foundation of China (11375176)
This paper describes the magnetic design of the magnets of the far-infrared free electron laser at NSRL, including dipole magnets and quadrupole magnets with limited installing space. The dipoles are of three different effective lengths and strengths. All the magnets are designed and optimized by using POSSION and OPERA-3D. The end shimming and chamfer are modeled and fully determined by 3D simulation to meet the field uniformity requirement. The design consideration and simulation results are presented in detail.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMB025

The Effect of Magnetic Field on the Secondary Electron Yield in the Ultra-High Vacuum Environment

gun, permanent-magnet, vacuum, synchrotron-radiation

3281

J. Wang, Y. Wang, W. Wei, Y.H. Xu, B. Zhang, T. Zhang, Y.X. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

A secondary electron emission measurement system has been designed and used to study the secondary electron emission (SEE) of different materials with an independently adjustable energy of 50 eV to 5 keV at National Synchrotron Radiation Laboratory. Here, we obtained the characteristics of the SEE yield from Pd film coatings, under the condition of magnetic field and without magnetic field. Then it was analysed that the effect of magnetic field on the secondary electron yield in the ultra-high vacuum environment. The results show that magnetic field shielding is critical to avoid the influence of magnetic field during secondary electron yield (SEY) measurements.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB025

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMB026

Research on Low Secondary Electron Yield Materials for Future Accelerators

vacuum, laser, proton, synchrotron-radiation

3284

J. Wang, Y. Wang, W. Wei, Y.H. Xu, B. Zhang, T. Zhang, Y.X. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

For future accelerators, such as SPPC (SEYmax <1.2), the build-up of electron cloud generated in the beam pipes considerably affect the stability of particle beams. Therefore, it is critical to look for steady and low secondary electron yield (SEY) material for future high intensity accelerators.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB026

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMB040

Charged Particle Transport, Gaussian Optics, Error Propagation: It's all the Same

optics, emittance, laser, beam-transport

3324

V.G. Ziemann
Uppsala University, Uppsala, Sweden

We derive a correspondence between the parameters used in Gaussian light beam propagation with wavelength, beam size, and wave front curvature to the description in terms of emittance and Twiss parameters commonly used in charged particle optics. Furthermore, we discuss the analogy of transporting beams to the propagation of measurement uncertainties.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB040

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMB048

Design and Optimisation of the ELENA Electron Cooler Gun and Collector

gun, solenoid, simulation, cathode

3354

G. Tranquille, J. Cenede
CERN, Geneva, Switzerland

Phase space compression of the antiproton beam in ELENA will be performed by a new electron cooler. The performance of the cooler is greatly influenced by the properties of the electron beam. Careful design of the electron gun electrodes, the quality of the guiding magnetic field and the efficient recuperation of the electrons in the collector ensure that the cooler performance is optimal. We have used COMSOL Multiphysics to design and optimise the complete electron cooler with particular attention to the gun and collector. This software suite uses physics interfaces for modelling common applications and then allows the user to combine the different interfaces in one multi-physics simulation.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB048

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMB052

Studies on Electron Beam Injector System for Linac-based Coherent Thz Source in Thailand

undulator, gun, linac, simulation

3366

W. Thongpakdi, S. Rimjaem
Chiang Mai University, Chiang Mai, Thailand

Funding: The Department of Physics and Materials Science, Faculty of Science, Chiang Mai University and the Development and Promotion of Science and Technology Talents Project (DPST).
At the Plasma and Beam Physics Research Facility, Chiang Mai University, a thermionic cathode RF electron gun and alpha magnet are used together as an injector system for a linac-based THz source. Investigate the optimal performance of the injector system, beam dynamic simulations are performed by computer codes PARMELA, ASTRA and ELEGANT. The input 3D field distributions of the RF-gun for PARMELA and ASTRA simulations are obtained from the RF modeling program CST Microwave Studio. The beam transport calculation using the program ELEGANT is performed to study behavior of electrons from the gun exit through the alpha magnet, a travelling wave linac, magnet elements, drift tubes, and related beam diagnostic components. Energy slits inside the alpha magnet vacuum chamber is used to select electrons with desired kinetic energies. The alpha magnet compresses electron bunches with certain bunch length before the beam entering the linac to obtain minimum energy spread and shortest bunch length at the experimental station. Results of electron beam optimization with appropriated conditions for generation of intense coherent THz radiation will be reported and discussed in this contribution.
This work has been supported by the CMU Junior Research Fellowship Program, the Department of Physics and Materials Science, Faculty of Science, Chiang Mai University and DPST.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB052

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMR010

Electron Polarization in the eRHIC Ring-Ring Design

polarization, storage-ring, synchrotron, solenoid

3403

V. Ptitsyn, C. Montag, S. Tepikian
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
High electron beam polarization (70-80%) is required in the future electron-ion collider eRHIC over the whole electron beam energy range from 5 GeV to 20 GeV. This paper analyzes important aspects for achieving a high electron polarization level in the ring-ring design option of eRHIC and presents the design of spin rotators required to generate the longitudinal polarization orientation at the interaction point. Experiment considerations require bunch spin patterns with both spins up and down. A highly polarized beam will be produced by a photo-injector, accelerated to full collision energy by an injector accelerator and injected into the storage ring. Beam depolarization time in the storage ring has to be minimized in the presence of spin rotators, detector solenoid and damping wiggler, which establishes specific requirements for the ring lattice.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMR010

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMR020

Bunch Purity Measurements at PETRA III

scattering, synchrotron, operation, timing

3434

J. Keil, H. Ehrlichmann
DESY, Hamburg, Germany

Since 2010 the 6 GeV synchrotron light source PETRA III is in operation. With a horizontal emittance of 1.2 nm*rad, a coupling of typically 1% and a total beam current of 100 mA the machine provides extremely brilliant synchrotron radiation for the users. For time-resolved measurements a filling pattern with 40 equidistant bunches with equal charge is used. To measure parasitic bunches between the main bunches two beamlines are equipped with avalanche photodiodes (APD) and time to digital converters (TDC) electronics. Besides parasitic bunches originating from the pre-accelerators of PETRA III it has been observed that initially empty buckets following the main bunch are populated. Measurements of the effect will be discussed and compared with simulations.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMR020

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMR034

Simulation of Single Particle Dynamics in a Compact Planar Wiggler

simulation, wiggler, focusing, synchrotron

3458

D.A. Shkitov, A.E. Harisova, Y.N. Sutygina
TPU, Tomsk, Russia

In this report a description of a simple approach how to simulate a single particle track in a 3D magnetic field using Radia code is presented. Such a simulation maybe useful in order to briefly estimate in a short time the beam dynamics in the magnetic field produced by means of different types of the magnet devices. As an example, a low energy relativistic electron tracking* is performed in a compact 30 cm planar wiggler which produced ~0.4 T magnetic field. The changes of the electron entrance point and motion direction are also available. This simulation is carried out using three-dimensional magnetostatic code - Radia**, where the 4th order Runge-Kutta method was implemented for the trajectory calculations. Since Radia is the Mathematica add-on then a small Wolfram Language code is developed to create the wiggler model, to calculate the electron trajectory and to illustrate the simulation results.
* Knyazik A. et al. Status of UCLA helical permanent-magnet undulator // Proc. of PAC, Canada, WE5RFP076 (2009) 2441
** http://www.esrf.eu/Accelerators/Groups/InsertionDevices/Software/Radia

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMR034

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMR048

Analysis of Nonlinear Effects for IDs at the SPS Storage Ring

coupling, storage-ring, injection, quadrupole

3512

S. Krainara, P. Klysubun, S. Kongtawong, T. Pulampong, P. Sudmuang, P. Sunwong
SLRI, Nakhon Ratchasima, Thailand

Funding: Synchrotron Light Research Institute (Public Organization)
To generate intense and high energy synchrotron radiation at the Siam Photon Source (SPS) 1.2 GeV storage ring, two insertion devices (IDs), namely, a 2.2 T hybrid multipole wiggler (MPW) and a 6.5 T superconducting wavelength shifter (SWLS), have been installed and operated since 2013. The angular kicks due to the nonlinear effects generated by the IDs represented by kick maps were used in our analysis. The optics distortion was compared to the ones obtained from calculation using hard-edge model and measurement results. In order to investigate the effects of IDs on the beam dynamics, Frequency Map Analysis (FMA) was employed. The effects of the IDs and their compensation are presented herewith.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMR048

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMR049

Minimization of Nonlinear Effects of Insertion Devices at SPS Storage Ring

wiggler, multipole, storage-ring, insertion

3515

P. Sunwong, P. Klysubun, S. Kongtawong, S. Krainara, T. Pulampong, P. Sudmuang
SLRI, Nakhon Ratchasima, Thailand
T. Pulampong
JAI, Oxford, United Kingdom

Funding: Synchrotron Light Research Institute PO. Box 93 Nakhon Ratchasima 30000 Thailand
Nonlinear effects of insertion devices were studied for the Siam Photon Source (SPS) storage ring. Despite the fact that shimming technique was used to minimize the nonlinear components of magnetic field integral arising from random errors, the nonlinear dynamics effects still remain. It was found that calculated dynamic field integrals are largest in the 2.2 T Hybrid Multipole Wiggler (MPW). Dynamics effects of insertion devices are attributed to the wiggling trajectory of electron in the region of magnetic field roll-off due to finite pole width. For better and more effective operation of the SPS storage ring, multipole components of the dynamic field integral in the MPW have to be further reduced.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMR049

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMR052

Compact, Microtron-Based Gamma Source

microtron, cathode, injection, cavity

3522

R.J. Abrams, M.A.C. Cummings, R.P. Johnson, S.A. Kahn, G.M. Kazakevich
Muons, Inc, Illinois, USA

Funding: This work was supported U.S. DOE SBIR Grant DE-SC0013795.
The conceptual design of a prototype S-band pulsed, 9.5 MeV compact microtron with type-II injection is described. Estimates of parameters such as beam current and cathode lifetime, and comparisons with X-band and C-band parameters are presented. The electron beam can be extracted at various energies up to 9.5 MeV. Estimated yields of gammas produced at 6.5 MeV operation and estimated yields of gammas and neutrons produced at 9.5 MeV are presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMR052

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMW017

Phase Shifter Power Supply Design

controls, simulation, power-supply, photon

3576

Y.T. Li, K.-B. Liu, B.S. Wang, Y.S. Wong
NSRRC, Hsinchu, Taiwan

Taiwan Photon Source is an interdisciplinary project. The phase-shift magnet is used to connect the radiation phase between two EPU48s. The power supply for this phase-shift magnet is a key element to determine the phase shift quality. In this report, the theory of the designed circuit is firstly introduced, and then a comparison simulation result and actual measurement is summarized to prove the correctness of theoretical analysis and circuit design.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW017

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMW040

Multipactor Discharge in a Resonator as an Active Switch for RF Pulse Compression

multipactoring, cavity, plasma, klystron

3640

J.Q. Qiu, S.P. Antipov, C.-J. Jing, A. Kanareykin
Euclid Beamlabs LLC, Bolingbrook, USA
E.V. Ilyakov, I.S. Kulagin, S.V. Kuzikov, A.A. Vikharev
IAP/RAS, Nizhny Novgorod, Russia

Funding: Phase I DOE SBIR
Pulse compression is a method of increasing the peak power of the microwave pulse at the expense of its length. Over the years a number of pulse compressors had been demonstrated with some being bulky but efficient, like the binary pulse compressor and other being compact but less efficient, like SLED-II. An active pulse compressor had been proposed to increase the efficiency and compression ratio which relies on a high power active switch. Currently there are no practical switches that can work reliably with 100 s of megawatts of power. Most of the switches (ferroelectric, plasma-based, semiconductor) are limited by the breakdown strength of various dielectric inserts. In this paper we report on an active switch development which is based on a pure copper resonator and controlled by a single-side multipactor discharge at a metallic wall in the presence of a resonant DC magnetic field and a normal to metal rf field. The discharge is ignited by external rf power produced by inexpensive 2.45 GHz, 1-5 kW magnetrons.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW040

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMW041

Single Crystal Diamond X-ray Lens Development

laser, optics, synchrotron, storage-ring

3643

S.P. Antipov, S.V. Baryshev, S. Baturin, R.A. Kostin
Euclid TechLabs, LLC, Solon, Ohio, USA
T.C. Irving, A. Olga
CSSRI, Chicago, USA
S. Stoupin
ANL, Argonne, Ilinois, USA

Funding: Phase I DOE SBIR
The next generation light sources such as diffraction-limited storage rings and high repetition rate free electron lasers (FELs) will generate x-ray beams with significantly increased peak and average brilliance. These future facilities will require x-ray optical components capable of handling large instantaneous and average power densities while tailoring the properties of the x-ray beams for a variety of scientific experiments. In this paper we report on research and development of a single crystal diamond compound refractive lens. Diamond is the best material for high heat load applications. Moreover single crystal lens preserves coherence of the x-ray beam because scattering from grain boundaries, voids and impurities, typical for current beryllium lenses is minimized. A set of two-dimensional single crystal diamond lenses had been fabricated by fs-laser cutting and tested at Advanced Photon Source (Argonne).

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW041

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMY007

Vacuum Performance of Amorphous Carbon Coating at Cryogenic Temperature with Presence of Proton Beams

cryogenics, vacuum, experiment, simulation

3663

R. Salemme, V. Baglin, G. Bregliozzi, P. Chiggiato
CERN, Geneva, Switzerland

Amorphous carbon (a-C) coating is the baseline electron multipacting mitigation strategy proposed for the Inner Triplets (IT) in the High Luminosity upgrade of the Large Hadron Collider (HL-LHC). As of 2014, the COLD bore EXperiment (COLDEX) is qualifying the performance of a-C coating at cryogenic temperature in a LHC type cryogenic vacuum system. In this paper, the experimental results following a cryogenic vacuum characterization of a-C coating in the 5 to 150 K temperature range are reviewed. We discuss the dynamic pressure rise, gas composition, dissipated heat load and electron activity observed within an accumulated beam time of 9 Ah. The results of dedicated experiments including pre-adsorption of different gas species (H2, CO) on the a-C coating are discussed. Based of phenomenological modeling, up-to-date secondary emission input parameters for a-C coatings are retrieved for electron cloud build-up simulations. Finally, first implications for the HL-LHC ITs design are drawn.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMY007

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMY010

LHC Beam Vacuum Evolution During 2015 Machine Operation

operation, proton, solenoid, luminosity

3673

C. Yin Vallgren, G. Bregliozzi, P. Chiggiato
CERN, Geneva, Switzerland

The LHC successfully returned to operation in April, 2015 after almost 2 years of Long Shutdown 1 (LS1) for various upgrade and consolidation programs. During 2015 operation, the LHC operated for more than 1000 fills. The 2015 LHC proton physics ended with 2244 bunches per beam circulating with 25 ns bunch spacing at top energy of 6.5 TeV. This paper summarizes the dynamic vacuum observations in different locations along the LHC during dedicated fills as well as during physics runs with both 50 ns and 25 ns bunch spacing. The causes for the dynamic pressure rises are investigated and are presented. A clear beam conditioning effect is observed, as well as a so-called de-conditioning effect. Furthermore, for the experimental areas, the dynamic pressure evolution is also presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMY010

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMY014

Study of the Non-evaporable Ti-Zr-V Films Grown on Different Materials

vacuum, experiment, synchrotron-radiation, booster

3682

L.H. Wu, C.M. Cheng, Y.T. Huang, S.Y. Perng, I.C. Sheng, C. Shueh
NSRRC, Hsinchu, Taiwan

The non-evaporable (NEG) Ti-Zr-V films were coated on the different vacuum-chamber materials, including the extruded aluminum samples (Al), the extruded seamless stainless steel samples (S.S.), CuCrZr alloys, and oxygen-free copper (OFC) plates. The NEG films were fabricated by using the direct current (DC) sputtering method. The secondary electron microscopy images showed that the morphology of NEG films was different on these various substrates. The thermal analysis (TA) presented that exothermic reaction happened by heating the samples.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMY014

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMY015

Measurement of the Pressure in the TPS Booster Ring

vacuum, booster, storage-ring, ion

3685

C.M. Cheng, C.K. Chan, G.-Y. Hsiung, Y.T. Huang, I.C. Sheng, L.H. Wu, I.C. Yang
NSRRC, Hsinchu, Taiwan

The booster ring of Taiwan Photon Source (TPS) is designed to provide full energy injection 3 GeV ramped up from 150 MeV with a small beam emittance. It is a synchrotron accelerator of circumference 496.8 m. The vacuum chamber through the magnets is made of thin stainless-steel tube extruded to an elliptical cross section of inner diameters 35 mm and 20 mm, and thickness 0.7 mm. The other chambers have standard 35CF round tube. The vacuum system was baked in the first installation. Because the residual stress of the stainless-steel elliptical tubing caused the magnetic field to become unstable, all elliptical tubing was removed for annealing to proceed, and reinstalled without baking. The ultimate pressure and data for the residual gas are shown as follows.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMY015

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMY016

Graphene Coating for the Reduction of the Secondary Electron Yield

cavity, vacuum, proton, framework

3688

B.S. Sian, G.X. Xia, G.L. Yu
UMAN, Manchester, United Kingdom
I. Kinloch, L. Lin, V. Valles
University of Manchester, Manchester, United Kingdom
O.B. Malyshev, R. Valizadeh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
O.B. Malyshev, R. Valizadeh, G.X. Xia
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Secondary electron emission is a limiting factor for a performance of many instruments ranging from small gauges and detectors to waveguides and charged particle accelerators. There have been several methods of reducing this effect, e.g. the method of using a material with a low Secondary Electron Yield (SEY) or thin film coating with such a low SEY material. This paper describes the effect of SEY mitigation with graphene coatings on aluminium substrate. The maximum SEY (dmax) was decreased from 2.4 for bare aluminium to 1.4 with a graphene coating. Measurements were taken using an electron gun and a Faraday cup, the electron energies varied between 80 eV and 1 keV with a bias of -18 V on the sample. Other biases of -3, -5, -9, -25, -50 and -75 V were also tested however there was no effect on the SEY.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMY016

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMY017

A Comparison of Surface Properties of Metallic Thin Film Photocathodes

laser, vacuum, survey, cathode

3691

S. Mistry, M.D. Cropper
Loughborough University, Leicestershre, United Kingdom
A.N. Hannah, L.B. Jones, K.J. Middleman, B.L. Militsyn, T.C.Q. Noakes, R. Valizadeh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

In this work physical vapour deposition magnetron sputtering has been employed to deposit metallic thin films onto Cu, Mo and Si substrates. The use of metallic thin films offers several advantages: (i) metal photocathodes present a fast response time and a relative insensitivity to the vacuum environment (ii) metallic thin films when prepared and transferred in vacuum can offer smoother and cleaner cathode surfaces. The photocathodes developed here will ultimately be used to drive NCRF guns such as that used in VELA and the proposed CLARA light source test facility. The samples grown on Si substrates were used to investigate the morphology and thickness of the film. The samples grown onto Cu and Mo substrates were analysed and tested as photocathodes in a surface characterisation chamber, where X-Ray photoelectron spectroscopy was employed to determine surface chemistry and a Kelvin probe apparatus used to determine work function. QE measurements were enabled using a 266 nm UV laser.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMY017

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMY039

RF Synchronization and Distribution for AWAKE at CERN

laser, proton, extraction, controls

3743

H. Damerau, D. Barrientos, T. Bohl, A.C. Butterworth, S. Döbert, W. Höfle, J.C. Molendijk, S.F. Rey, U. Wehrle
CERN, Geneva, Switzerland
J.T. Moody, P. Muggli
MPI-P, München, Germany

The Advanced Wakefield Experiment at CERN (AWAKE) requires two particle beams and a high power laser pulse to arrive simultaneously in a rubidium plasma cell. A proton bunch from the SPS extracted about once every 30 seconds must be synchronised with the AWAKE laser and the electron beam pulsing at a repetition rate of 10 Hz. The latter is directly generated using a photocathode triggered by part of the laser light, but the exact time of arrival in the plasma cell still depends on the phase of the RF in the accelerating structure. Each beam requires RF signals at characteristic frequencies: 6 GHz, 88.2 MHz and 10 Hz for the synchronisation of the laser pulse, 400.8 MHz and 8.7 kHz for the SPS, as well as 3 GHz to drive the accelerating structure of the electron beam. A low-level RF system has been designed to generate all signals derived from a common reference. Additionally precision triggers, synchronous with the arrival of the beams, will be distributed to beam instrumentation equipment. To suppress delay drifts of the several kilometer long optical fibres between AWAKE and the SPS RF systems, a compensated fibre link is being developed.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMY039

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMY041

Neodymium and Ytterbium Hybrid Solid Laser of RF Gun for SuperKEKB

laser, cavity, linac, polarization

3748

X. Zhou, T. Natsui, Y. Ogawa, M. Yoshida, R. Zhang
KEK, Ibaraki, Japan
T. Shibuya
TIT, Tokyo, Japan

The electrum beam of the repetition rate of 50 Hz double-bunch is requested for injector linac of SuperKEKB. By development of the Yb-doped laser system, more than 5.0 nC and 3.0 nC electron beam with single-bunch has been generated in the 5 Hz and 25 Hz respectively. Also more than 1.0 nC electron with double-bunch has been obtained in 25 Hz. The Yb-doped laser system is already for commissioning for the linac. Next, a new laser system is development to improve the stability and reliability. The laser system starts with a 50 MHz Yb-doped fiber oscillator with the all normal dispersion (ANDi) structure. A transmission grating pair stretcher was employed to expend pulse to ~30 ps and separate the pulse to two parts with the center wavelength of 1030 nm and 1064 nm. Then the two kinds of pulses can be amplified by Yb:YAG and Nd:YAG crystals respectively. The weak pulses were amplified by the Yb-doped fiber amplifier, and reduced repetition rate by a semiconductor optics amplifier (SOA) pulse picker. To obtain the mJ-class pulse energy, a Yb:YAG thin-disk regenerative solid-state amplifier and a Nd:YAG rod regenerative solid-state amplifier were employed.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMY041

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMY042

Laser Applications at Accelerators

laser, network, ion, accelerating-gradient

3751

C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: This project has received funding from the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement no 289191.
The LA3NET consortium has developed advanced laser applications for particle accelerators within an international research and training network. It brought together research centers, universities, and industry partners to carry out collaborative research into all the above areas and jointly train the next generation of researchers. This contribution presents selected research highlights from the LA3NET network. It shows how enhanced ionization schemes can provide better ion beams for radioactive beam facilities, and how RF photo injectors can produce high brightness electron beams. It also presents results from studies into ultra-compact, fiber optics-based electron accelerators and new radiation sources based on laser accelerated beams. Finally, it summarizes how electro-optical techniques, laser velocimeters, and laser emittance meters can all help characterize beams with better time and spatial resolution in non-invasive ways.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMY042

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMY043

Collimation System Design for LCLS-II

undulator, linac, collimation, gun

3755

M.W. Guetg, P. Emma, M. Santana-Leitner, J.J. Welch, F. Zhou
SLAC, Menlo Park, California, USA

Funding: DOE contract \#DE-AC02-76SF00515
The planned LCLS-II FEL has an average beam power of up to 1.2 MW and a repetition rate of up to 1 MHz, both of which entail serious challenges for beam halo collimation. This paper summarizes the efforts to assess the proposed collimation system. The undulator section is specifically focused on due to its high loss sensitivity (maximal 12 mW). This proceedings concentrate on field emissions of the gun. Different dark current distribution, linac configurations and simulation programs were used to increase assurance of the results. Filled phase-space tracking further supplemented an independent prove of the collimation system effectiveness and expands to include beam-halo originating from different sources than the gun.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMY043

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOR018

Comissioning of Upgraded VEPP-2000 Injection Chain

injection, positron, booster, linac

3811

D.E. Berkaev, A.V. Andrianov, K.V. Astrelina, V.V. Balakin, A.M. Barnyakov, O.V. Belikov, M.F. Blinov, D.V. Bochek, D. Bolkhovityanov, F.A. Emanov, A.R. Frolov, K. Gorchakov, Ye.A. Gusev, A.S. Kasaev, E. Kenzhbulatov, I. Koop, I.E. Korenev, G.Y. Kurkin, N.N. Lebedev, A.E. Levichev, P.V. Logatchov, A.P. Lysenko, D.A. Nikiforov, V.P. Prosvetov, Yu. A. Rogovsky, S.L. Samoylov, A.I. Senchenko, P.Yu. Shatunov, Y.M. Shatunov, D.B. Shwartz, A.A. Starostenko, I.M. Zemlyansky, Yu.M. Zharinov
BINP SB RAS, Novosibirsk, Russia
F.A. Emanov, Yu. A. Rogovsky, A.I. Senchenko, A.A. Starostenko
NSU, Novosibirsk, Russia

The upgrade of VEPP-2000 e⁺e⁻ collider injection chain includes the connection to BINP Injection Complex (IC) via newly constructed transfer line K-500 as well as upgrade of the booster synchrotron BEP to the energy of 1 GeV. Modernization has started in the middle of 2013 and now the electron and positron beams with highly increased production rate together with top-up injection from BEP are ready to feed VEPP-2000 ring and provide design luminosity at the whole energy range limited only by beam-beam effects. The design and operation experience of IC damping ring, 250 m transfer channel and booster BEP dealing with 2.6 T magnets at top energy will be presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR018

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOR035

Development of a Low-latency, Micrometre-level Precision, Intra-train Beam Feedback System based on Cavity Beam Position Monitors

feedback, cavity, kicker, extraction

3862

N. Blaskovic Kraljevic, R.M. Bodenstein, T. Bromwich, P. Burrows, G.B. Christian, M.R. Davis, C. Perry, R.L. Ramjiawan
JAI, Oxford, United Kingdom
D.R. Bett
CERN, Geneva, Switzerland

A low-latency, intra-train, beam feedback system utilising a cavity beam position monitor (BPM) has been developed and tested at the final focus of the Accelerator Test Facility (ATF2) at KEK. A low-Q cavity BPM was utilised with custom signal processing electronics, designed for low latency and optimal position resolution, to provide an input beam position signal to the feedback system. A custom stripline kicker and power amplifier, and a digital feedback board, were used to provide beam correction and feedback control, respectively. The system was deployed in single-pass, multi-bunch mode with the aim of demonstrating intra-train beam stabilisation on electron bunches of charge ~1 nC separated in time by c. 220 ns. The system has been used to demonstrate beam stabilisation to below the 75 nm level. Results of the latest beam tests, aimed at even higher performance, will be presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR035

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOR037

TW-Structure Design and E-Field Study for CLIC Booster Linac

linac, booster, cavity, positron

3868

E. Darvish Roknabadi
IPM, Tehran, Iran
S. Döbert
CERN, Geneva, Switzerland

Using the SUPERFISH code we present a design for a traveling wave (TW) structure of the Booster Linac for CLIC. The structure, consisting of thirty asymmetric cells attached to the beam pipes at two ends, works in 2Pi/3 operating mode at working frequency 2 GHz. The RF field transmitted through the designed cavity is prepared in an RF field data file to be used in the PARMELA code. We will then compare the resultant output PARMELA field with that of the ideal RF field which obtained from the usual method for a traveling wave structure.
* Based on CLIC Note 1051, 2015

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR037

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOR045

Analytical Estimation of ATF Beam Halo Distribution

scattering, emittance, vacuum, damping

3888

D. Wang, J. Gao
IHEP, Beijing, People's Republic of China
P. Bambade
LAL, Orsay, France
T. Naito
KEK, Ibaraki, Japan

Funding: Work supported by the National Foundation of Natural Sciences (11505198 and 11575218)
Halo distribution is a key topic for background study. This paper has developed an analytical method to give an estimation of ATF beam halo distribution. The equilibrium particle distribution of the beam tail in the ATF damping ring is calculated analytically with different emittance and different vacuum degree. The analytical results agree the measurements very well. This is a general method which can be applied to any electron rings.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR045

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOR046

CEPC 650 MHz Klystron Development

klystron, gun, simulation, operation

3891

Z.S. Zhou, D. Dong, S. Fukuda, Z.J. Lu, G. Pei, S.C. Wang, O. Xiao, .. Zaib-un-Nisa
IHEP, Beijing, People's Republic of China
S. Fukuda
KEK, Ibaraki, Japan

The CEPC collider beam power is about 100 MW, so the efficiency of amplifier is very important for cost of project implementation. The high power klystron is the more attractive because of its potential for higher eﬃciency than solid state amplifier. For CEPC klystron output power is not so high, the operation voltage can be a safe value. Advantage for single beam: reliable, low phase noise, some perspective technology can be used to improve efficiency. The accelerating frequency is 650 MHz, output power is a maximum power of 800kW, and efficiency is about 70%. In this paper, the specifications and developments of 650 MHz CW klystron, including the klystron gun prototype and future high efficiency consideration are summarized.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR046

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW002

Electromagnetic, Thermal, and Structural Analysis of a THOMX RF Gun Using ANSYS

gun, cavity, coupling, simulation

3925

M. El Khaldi, J. Bonis, A. Camara, L. Garolfi, A. Gonnin
LAL, Orsay, France

Photocathode RF guns are used in the first stage of electron beam generation and acceleration. The RF gun of THOMX is a 2.5 cell standing wave copper cavity with resonance frequency of 2998.55 MHz at 30 °C under vacuum. The metal photocathode such as copper or magnesium is inserted into the backplane of the cavity. Due to high repetition rates up to 50 Hz with the average dissipated power into the internal surfaces up to 1.5 kW, causing a heating and deformation of the cavity shape. Therefore, the cooling system of the device has to be well designed to take under control the deformations of the structure, providing a temperature increase as small and uniform as possible. For this purpose a fully coupled electromagnetic-thermal-structural finite element analysis on this gun has been performed with Ansys workbench. Numerical results show that the gun could operate at 3 μs RF pulse length and 50 Hz repetition rate with an average dissipated power of 1.5 kW. The gun average temperature is around 30 °C while the incoming water temperature is around 24°C. Internal speed of water is 2.5 m/s which corresponds to 15 l/min for the incoming water. The total pressure drop is around 0.4 bar

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW002

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW004

Pulse Response Measurements of NEA Photocathodes at Different Laser Wavelengths

laser, cavity, photon, cathode

3931

M.A. Dehn, K. Aulenbacher, V. Bechthold
IKP, Mainz, Germany

For high average electron beam currents the length of the electron bunches must match the acceptance of the accelerator. At Johannes Gutenberg-University Mainz we are able to measure the longitudinal pulse response of NEA photocathodes (GaAs) under photo excitation of different wavelengths. A time resolution of < 2 ps at a beam energy of 100 keV is achieved, furthermore, a high dynamic range allows to investigate long ranging tails of the response (longitudinal halo). This serves to identify the best possible operation mode for high current photo sources.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW004

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW005

A Study of CsK2Sb Multi-alkali Photocathode by Ultraviolet Photoelectron Spectroscopy at UVSOR

cathode, laser, experiment, vacuum

3934

M. Urano, M. Kuriki, K. Negishi
HU/AdSM, Higashi-Hiroshima, Japan
T. Konomi, Y. Seimiya, N. Yamamoto
KEK, Ibaraki, Japan

Photocathode is one of the most important components in the next-generation accelerators, especially based on linear accelerators. Photocathode performance depends not only on electronic state in its bulk material but also on the surface condition. CsK2Sb multi-alkali photocathode is a candidate for the high brightness electron source because of its high quantum efficiency by green laser and its high robustness. We have carried out an UPS (UV Photoelectron Spectroscopy) experiment at UVSOR facility, synchrotron radiation light source in Aichi Japan. We have compared the UPS spectra among several samples, each one has a different quantum efficiency, and try to find physics which decide photocathode's performance. In this case, we focused some characters correlated to the quantum efficiency. I'm going to present a result of this analysis.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW005

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW006

A Study of Operational Lifetime of CsK2Sb Photo-cathode

cathode, laser, vacuum, storage-ring

3938

A. Yokota, R. Kaku, M. Kuriki, K. Negishi, M. Urano
HU/AdSM, Higashi-Hiroshima, Japan
Y. Seimiya
KEK, Ibaraki, Japan

A high performance electron beam generated with a laser photo-cathode is one of the most important pieces in the advanced accelerator. Because the CsK2Sb photo-cathode is robust with more than 10 % quantum efficiency (QE) by green laser (532nm), it is considered to be the best candidates of the cathode for Energy Recovery Lin-ac (ERL) and Free Electron Laser (FEL) requiring a high brightness beam. We developed a system to evaporate the cathode as a thin film in vacuum to study the cathode performance. The cathode operational lifetime regarding not only on time, but also extracted charge density was studied. We found the lifetime is long enough for practical use in an accelerator.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW006

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW007

Cs2Te Photocathode Response Time Measurements and Femtosecond Comb Electron Beam Generation as a Milestone Towards Pre-Bunched Thz Fel Realization

radiation, laser, gun, FEL

3941

A. Aryshev, Y. Honda, K. Lekomtsev, M. Shevelev, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan

Funding: Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan and JSPS KAKENHI: 23226020 and 24654076
Currently there is a rapidly growing demand to increase the brightness of electron beams generated by conventional RF guns as well as to decrease the cost of the injector accelerator system for many research facilities worldwide. To address this demand we investigate one of the most important parameter of the high Q.E. conventional semiconductor Cs2Te photocathode, its response time. It sets the principle limitation for generated bunch length and hence maximum achievable beam brightness of electron diffraction and pre-bunched THz FEL facility's injectors. The experimental investigation was done at KEK: LUCX facility. The Cs2Te photocathode response time better than 250 fs was demonstrated. The generation of 4 micro-bunch comb electron beam with variable time separation as a crucial technology for pre-bunched THz FEL realization was achieved.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW007

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW009

Optimal Design of a Photocathode Electron Gun with High-brightness and High-repetition Rate Based on Genetic Algorithm

gun, impedance, cavity, laser

3947

Zh. X. Tang, X.M. Yang, W.Q. Zhang
DICP, Dalian, People's Republic of China
Y.J. Pei, Y. Yu
USTC/NSRL, Hefei, Anhui, People's Republic of China

A low RF frequency of normal conducting photocathode gun with high-brightness and high-repetition rate is designed as an electron source of the Next Generation Light Source (NGLS). In order to optimize the performance of the gun, a genetic multi-objective algorithm has been used. A genetic algorithm is used because of the inherent complexity of the large number of parameters of the cavity geometry available for optimization. On the other hand, the multiplicity of requirements on the beam, which include beam emittance, beam pulse length, energy chirp, as well as pulse shape and peak current, leads to a multi-objective approach for the optimization technique. In this paper, we present the status of the optimization simulations, using the SUPERFISH and PERMELA particle-in-cell code.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW009

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW010

Study on Characteristics of Asymmetric Centre Iris of Photocathode Microwave Electron Gun

gun, emittance, electromagnetic-fields, cathode

3951

Zh. X. Tang, X.M. Yang, W.Q. Zhang
DICP, Dalian, People's Republic of China
Y.J. Pei
USTC/NSRL, Hefei, Anhui, People's Republic of China

The characteristics of asymmetric iris between first cell and second cell of 1.6 cell photocathode gun are studied. For π-mode, the RF radial field of two sides of the iris is non anti-symmetric. Thus, the RF transverse force at the iris is not negligible. In this paper, we present the status of the optimization simulations, using the SUPERFISH and PARMELA particle-in-cell code. Numerical results of beam dynamics show that it can improve the emittance at the exit of the gun.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW010

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW011

The Measurement System of the Electron Gun with Double-anode Structure

gun, cathode, vacuum, high-voltage

3954

F.L. Shang, J. Li, L. Shang
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: National Natural Science Foundation of China(11175181); National Natural Science Foundation of China(10875116)
The double-anode structure with an intermediate electrode has been proposed to overcome the strong space-charge force on the cathode and improve the transverse focusing, which make the goal of high perveance and high compression ratio achieved. This gun plays a key role as the external injecting electron source of the independently-tunable-cells (ITC) RF gun. In order to understand the quality of the beam, a measurement system has been designed. The papers present the measurement system and the result of the test.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW011

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW015

Study of the Performance of Cs2Te Cathodes in the PHIN RF Photoinjector using Long Pulse Trains

cathode, vacuum, operation, laser

3960

C. Heßler, E. Chevallay, S. Döbert, V. Fedosseev, F. Friebel, I. Martini, M. Martyanov, H. Neupert, V. Nistor, M. Taborelli
CERN, Geneva, Switzerland

The drive beam of CLIC requires unusually high peak and average currents which is challenging for the electron source. As an alternative to the thermionic electron gun foreseen in the baseline design, a photoinjector option is under study at CERN using the PHIN photoinjector, which was designed for a bunch charge of 2.3 nC and 1200 ns train length. During operation with nominal train length in 2014, a large pressure increase in the vacuum system, attributed to a heating of the Faraday cup, caused a degradation of the photocathode. To overcome this problem a vacuum window has been installed to separate the Faraday cup from the rest of the vacuum system. In addition the train length has been further increased to 1600 ns to advance the beam parameters towards CLIC requirements. In this paper recent improved photocathode lifetime measurements carried out under these new conditions will be presented and compared with earlier measurements. Furthermore, the utilized Cs2Te cathode has been analyzed with X-ray Photoelectron Spectroscopy (XPS) before and after its usage in PHIN to get a better understanding of photocathode surface deterioration effects, which will also be discussed.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW015

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW016

Transverse Energy Spread Measurements from GaAs Photocathodes at Variable Wavelengths

cathode, detector, laser, photon

3964

T.C.Q. Noakes, R. Beech, L.B. Jones, B.L. Militsyn
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
H.E. Scheibler, A.S. Terekhov
ISP, Novosibirsk, Russia

The transverse energy spread spectrometer (TESS) is an instrument specially developed at Daresbury Laboratory to measure the intrinsic transverse and longitudinal energy distributions from photocathode materials. Early work on the instrument has focussed on its use for the characterisation of GaAs photocathodes such as those commonly used in DC photoinjectors. More recently work has been conducted to extend the range of materials which can be evaluated using this apparatus, in particular by incorporating a monochromated white light source. New results are presented using the white light source to measure the energy spread of a GaAs photocathode across a range of different wavelengths to evaluate how this changes with excess energy.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW016

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW017

VELA Photoinjector Cavity RF Investigations

cathode, cavity, simulation, operation

3968

L.S. Cowie, B.L. Militsyn
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
J.A. Mitchell
Lancaster University, Lancaster, United Kingdom
M.D. Roper
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

One of two ALPHA-X photocathode gun cavities, designed and fabricated at the Laboratoire de l'Accélérateur Linéaire, has been in operation on the VELA electron accelerator at Daresbury Laboratory since first beam in April 2013. In this time the maximum beam momentum recorded is 5.06 MeV/c. An investigation of the cavity has been performed with the aim of reconciling the expected momentum of over 6 MeV/c with the measured momentum. RF and beam simulation results are presented along with low power RF measurements of the cavity. One source of momentum loss, the flatness of the cathode face, is identified and rectified.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW017

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW018

Simulations of Field Emitted Dark Current Dynamics in DC Photoinjectors

simulation, gun, cavity, space-charge

3971

P.J. Tipping, J.W. McKenzie, B.L. Militsyn
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Field emission is a concern in injectors with DC photoelectron guns because of the constant generation of dark current, which is accelerated down the beam line and can deteriorate the photoemitted bunch quality and lead to hardware damage. Simulations were carried out on the co-propagation of a field emitted, dark current halo and a photoemitted bunch in a typical 350 kV gun as used in an ERL or FEL injector, followed by a single cell buncher cavity. The photoemitted bunch repelled the halo longitudinally, leaving the area in the centre of the bunch with very low dark current, surrounded by two peaks of relatively high current at the front and back of the bunch. The peaks in current occur at all levels of dark current and were about 3.5 times the amplitude of the undisturbed dark current. The buncher caused the dark current to overcompress, forming a 'ghost' pulse an order of magnitude larger than the initial level of dark current, in front of the photoemitted bunch.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW018

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW019

Beam Characterisation and Machine Developments at VELA

experiment, gun, cathode, space-charge

3975

D. Angal-Kalinin, A.D. Brynes, F. Jackson, S.P. Jamison, J.K. Jones, J.W. McKenzie, B.L. Militsyn, B.D. Muratori, T.C.Q. Noakes, M.D. Roper, Y.M. Saveliev, D.J. Scott, R.J. Smith, E.W. Snedden, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
S.D. Barrett, C.P. Topping, A. Wolski
The University of Liverpool, Liverpool, United Kingdom
C.S. Edmonds, F. Jackson, S.P. Jamison, J.K. Jones, J.W. McKenzie, B.D. Muratori, Y.M. Saveliev, D.J. Scott, C.P. Topping, P.H. Williams, A. Wolski
Cockcroft Institute, Warrington, Cheshire, United Kingdom

An overview is presented of developments on VELA (Versatile Electron Linear Accelerator), an RF photo-injector with two user stations at Daresbury Laboratory. Numerous commissioning, machine development, beam characterisation and user experiments have been completed in the past year. A new beamline and a dedicated multiuser station have been commissioned and the first experiments performed. A number of measures have been taken to improve the stability of machine by mitigating a phase drift, laser beam transport drift and a coherent ~1 Hz beam oscillation. The 6D phase space of the electron beam has been characterised through quad scans, transverse tomography and with a transverse deflecting cavity.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW021

Generation of Homogeneous and Patterned Electron Beams using a Microlens Array Laser-Shaping Technique

laser, emittance, solenoid, experiment

3983

A. Halavanau, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
D.R. Edstrom, P. Piot, J. Ruan, J.K. Santucci
Fermilab, Batavia, Illinois, USA
W. Gai, G. Ha, J.G. Power, E.E. Wisniewski
ANL, Argonne, Illinois, USA
G. Ha
POSTECH, Pohang, Kyungbuk, Republic of Korea
G. Qiang
TUB, Beijing, People's Republic of China

Funding: Northern Illinois University - US DOE contract No. DE-SC0011831. Fermilab - US DOE contract No. DE-AC02-07CH11359. The Argonne wakefield facility - US DOE contract No. DE-AC02-06CH11357.
In photocathodes the achievable electron-beam parameters are controlled by the laser used to trigger the photoemission process. Non-ideal laser distribution hampers the final beam quality. Laser inhomogeneities, for instance, can be "amplified" by space-charge force and result in fragmented electron beams. To overcome this limitation laser shaping methods are routinely employed. In the present paper we demonstrate the use of simple microlens arrays to dramatically improve the transverse uniformity. We also show that this arrangement can be used to produce transversely-patterned electron beams. Our experiments are carried out at the Argonne Wakefield Accelerator facility.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW023

Intrinsic Emittance Reduction in Transmission Mode Photocathodes

emittance, scattering, laser, cathode

3987

H. Lee, I.V. Bazarov, L. Cultrera
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

High quantum efficiency (QE) and low emittance electron beams provided by multi-alkali photocathodes make them of great interest for next generation high brightness photoinjectors. Spicer's three-step model well describe the photoemission process, however, some photocathode characteristics such as their thickness have not been completely exploited to further improve the brightness of the generated electron beam. In this work, we report on the emittance and QE of a multi-alkali photocathode grown onto glass substrate operated in transmission and reflection modes at different photon energies. We observed a 20% reduction on the intrinsic emittance from the reflection to the transmission mode operation. This observation can be explained by inelastic electron-phonon scattering events experienced by electrons during their transit towards the cathode surface. This scattering will expect the further emittance reduction than the no scattering at the cryo-temperatures.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW023

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW025

Photocathode Growth and Characterization Advances at Cornell University

photon, emittance, cathode, gun

3990

L. Cultrera, A.C. Bartnik, I.V. Bazarov, B.M. Dunham, C.M. Gulliford, H. Lee, R.A. Lipton, T.P. Moore
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Alkali-antimonides based photocathodes have demonstrated outstanding performance in high brightness electron beam production suitable for a wide range of applications such as FELs, ERLs and UED and for use in photomultiplier devices with picosecond resolution aimed at photon counting application in medicine and High Energy Physics. The photocathode laboratory at Cornell University is dedicated to studying the growth procedures and characterizing the properties in a wide range of photocathodes materials. Different experimental arrangements and alkali metal sources have been successfully explored to date to synthesize photosensitive materials. Recent work on commissioning a new growth chamber equipped with effusion cells loaded with pure metal allowing uniform deposition over large area substrates resulted on successful growth of photocathodes with extended sensitivity in the IR part of the spectrum and high efficiency alkali antimonides containing Rb metal. This and other advances aimed at demonstrating superior photocathodes will be presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW025

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW026

LLNL X-band RF Gun Results

laser, emittance, gun, dipole

3993

R.A. Marsh, G.G. Anderson, C.P.J. Barty, D.J. Gibson
LLNL, Livermore, California, USA
Y. Hwang
UCI, Irvine, California, USA

Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344
An X-band test station and Inverse Compton Scattering (ICS) x-ray source has been built and commissioned at LLNL. The electron beam source is a unique 5.59 cell RF photoinjector, which will be described in detail, including: quantum efficiency, emittance measurements, energy spread and jitter, final focus spot size and stability, laser profile and final transport, and consistency with expectations based on beam dynamics simulations.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW026

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW029

Single Electron Extraction at the ELSA Detector Test Beamline

extraction, synchrotron, injection, detector

4002

F. Frommberger, N. Heurich, W. Hillert, T. Schiffer, M.T. Switka
ELSA, Bonn, Germany

The Electron pulse Stretcher Facility ELSA delivers polarized and non-polarized electrons with an adjustable beam energy of 0.5 - 3.2 GeV to external experimental stations. Extraction currents available range down from 1 nanoampere to several atto-amperes provided by single electron extraction. Especially the high energy physics community requires detector test stations with electron tagging rates between 100 Hz to 100 kHz, imposing particular requirements for stable minimum-current extraction from the storage ring. These requirements are met with the implementation of a low-injection mode for the booster synchrotron and photomultiplier-based stored current monitoring, providing feedback for a selectable limit of the injected current. A homogeneous extraction current with duty factor > 80% is routinely granted by the excitation of a 3rd integer optical resonance. The setup of the low-current injection system and measurements of the extraction properties at the preliminary detector test beamline are presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW029

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW030

ELI Eectron Beam Line for Laser-plasma-driven Undulator X-ray Source

undulator, quadrupole, laser, photon

4005

A.Y. Molodozhentsev
KEK, Ibaraki, Japan
L. Pribyl
Czech Republic Academy of Sciences, Institute of Physics, Prague, Czech Republic

ELI LUX experiment of the ELI-Beamlines Project is based on electron beam, accelerated by the laser plasma wakefield. ELI LUX aims to deliver for users the X-ray beams with radiation length (0.4-4.5)nm and the peak brilliance up to 10²³ photons/(s mrad2 mm2 0.1% B.W.), which makes this source comparable with modern synchrotron sources. To provide small transverse size of the electron beam and small transverse beam divergence in the undulator, permanent quadrupole magnets with high gradient of the magnetic field up to 510 T/m are used in the electron beam line. In frame of this report we present main features of the designed electron beam line. 3D modeling of the magnetic field in the quadrupole magnets has been performed. Effects of the chromatic and spherical aberrations are taken into consideration. The electron beam dynamic is studied by using symplectic integration though the 3D field maps of the permanent quadrupole magnets. Effects of the space charge of the electron beam, beam collimation, injection and alignment errors and realistic field errors are discussed. Finally parameters of the photon beam, generated in compact undulator, are presented in this report.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW030

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW034

TLS Booster Injection Scheme Exploration

booster, septum, injection, kicker

4016

H.H. Chen, H.-P. Chang, H.C. Chen, S.J. Huang, C.H. Kuo, A.P. Lee, J.A. Li, K.-K. Lin, Y.K. Lin
NSRRC, Hsinchu, Taiwan

In this paper, the booster injection efficiency and the parameter working range related to key components in-cluding septum magnet and kicker magnet for Taiwan Light Source (TLS) injector operation are introduced. Booster injection scheme for different lattice is explored by machine study plan using injector property. The study result may be used by the operator as booster injection parameter fine tuning reference. It is also helpful for the advanced injection scheme exploration.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW034

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW036

Evaluation of Immutability against Radiation-induced Demagnetization for a Hybrid Wiggler with NdFeB Magnets at the Canadian Light Source

radiation, wiggler, injection, operation

4022

C.K. Baribeau, D. Bertwistle, L.O. Dallin, J.M. Vogt, W.A. Wurtz
CLS, Saskatoon, Saskatchewan, Canada

The BioXAS beamline at Canadian Light Source installed a hybrid wiggler in 2013. Quantitative studies building on the experience of other facilities suggest the wiggler's NdFeB magnets are at risk of demagnetization due to radiation induced by the synchrotron's 2.9 GeV electrons. We use a phenomenological model to convert simulated peak demagnetizing fields into a radiation dose corresponding to a chosen %-demagnetization, and compare against an estimated dose per year due to injected beam. We find that injecting with the wiggler closed will cause 1% demagnetization in sections of its magnet blocks within 2 years of operation, assuming a worst case scenario. The wiggler has thus far been forced open for injections, but this will cease to be an option when CLS moves to top-up operation. In a related test, qualitative measurements of radiation during injections with the wiggler closed were taken by covering its magnets in Polaroid film. We find that radiation drops significantly when the injection efficiency is well-tuned. Our results suggest the wiggler will not receive damaging levels of radiation at closed gap so long as the injection system remains optimized.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW036

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW040

Insertion Devices for Spring-8 Upgrade Project

undulator, vacuum, storage-ring, polarization

4035

T. Tanaka, T. Hasegawa, R. Kinjo
RIKEN SPring-8 Center, Hyogo, Japan
T. Bizen, A. Kagamihata, H. Kishimoto, H. Ohashi, T. Seike
JASRI/SPring-8, Hyogo, Japan
S. Yamamoto
KEK, Tsukuba, Japan

In the upcoming major upgrade project of SPring-8 (SPring-8-II) planned in the early 2020's, the electron energy will be reduced from 8 GeV to 6 GeV and the straight sections will be shortened by nearly 2 m to accommodate more magnets, for the purpose of reducing the emittance down to around 100 pm.rad. The insertion devices (IDs) currently installed in SPring-8 are not compatible with the above upgrade plan, and thus most of them should be replaced with new ones optimized in the new storage ring, or at least be shortened to fit into the new straight sections. We report the status of R&Ds toward realization of IDs for SPring-8-II, such as shortening the magnetic period, reforming the fundamental structure of IDs to reduce the total cost and manufacturing lead time, and refurbishment of existing IDs for shorter lengths.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW040

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW041

Field Error Correction Considerations of Cryogenic Permanent Magnet Undulator (CPMU) for High Energy Photon Source Test Facility (HEPS-TF)*

cryogenics, undulator, simulation, operation

4038

Y.F. Yang, H.H. Lu, S.C. Sun, X.Z. Zhang
IHEP, Beijing, People's Republic of China

Considerations are made for field error corrections of a 2m-long CPMU in built for HEPS-TF. Field changes in cooling to liquid nitrogen temperature are simulated. 1st field integral of terminal changes by tens of Gauss cm and RMS of phase errors induced by cold contraction is less than 1° when temperature gradient along girder is below 1.5K/m. Field signature of magic finger is unchanged with temperature. Strategy of the field error correction is discussed.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW041

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW042

Start-to-End Simulation on Terahertz Superradiation of Ultrashort Electron Bunch in an Undulator

radiation, undulator, simulation, laser

4041

X.L. Su, Y.-C. Du, W.-H. Huang, C.-X. Tang, D. Wang, L.X. Yan, Z. Zhang
TUB, Beijing, People's Republic of China

The narrowband, intense and frequency-tunable THz radiation can be generated by letting an ultrashort electron bunch pass through an undulator. Start-to-end simulation of terahertz radiation from electron bunch in an undulator is studied in this paper. GPT code is used to track particle distribution from the photocathode RF gun to the entrance of the undulator and Genesis 1.3 is applied to simulate the radiation. The simulation results agree well with theoretical predictions.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW042

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW045

Development of PAL-XFEL Undulator System

undulator, FEL, laser, radiation

4044

D.E. Kim, Y.-G. Jung, H.-S. Kang, I.S. Ko, H.-G. Lee, S.B. Lee, W.W. Lee, B.G. Oh, K.-H. Park, H.S. Suh
PAL, Pohang, Kyungbuk, Republic of Korea
J. Pflüger
XFEL. EU, Hamburg, Germany

Pohang Accelerator Laboratory (PAL) is developing a 0.1 nm SASE based FEL based on 10 GeV S-band linear accelerator named PAL-XFEL. At the first stage, PAL-XFEL needs two undulator lines for photon source. The hard X-ray undulator line requires 20 units of 5 m long hybrid-type conventional planar undulator and soft X-ray line requires 7 units of 5 m long hybrid type planar undulators. PAL is developing undulator magnetic structure based on EU-XFEL concepts. In this report, the results of final pole height tuning results, and magnetic measurement results will be presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW045

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW048

Optimization of a Multipole Wiggler for Tps

photon, wiggler, radiation, permanent-magnet

4050

J.C. Jan, C.-H. Chang, T.Y. Chung, J.C. Huang, C.-S. Hwang, C.Y. Kuo
NSRRC, Hsinchu, Taiwan

Taiwan Photon Source (TPS) is a synchrotron radia-tion facility with electron energy 3 GeV that was commissioned in 2015. Taiwan Light Source (TLS) with electron energy 1.5 GeV concurrently provides user time. Three beam lines of TLS supply photons of energy 6-18 keV for user experiments; these beam lines are served with an in-achromatic superconduct-ing wiggler (IASW, 3.1 T). This superconducting inser-tion device has the disadvantages of complicated maintenance and operation. A traditional multipole wiggler (MPW) magnet of hybrid type is hence planned to be installed in TPS to cover the range of photon energy of IASW for user experiments. For the design of the magnetic circuit, the side block and the extreme block are arranged surrounding a Permendur Vanadium cobalt steel pole that enhances the field strength and good field region of a MPW magnet. The dynamic integral field and the demagnetizing field of MPW magnet were estimated. The optimization of the pole dimensions and photon characteristics were simu-lated and are discussed in this work.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW048

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW051

Design and Construction of Compact Electromagnetic Undulator for THz Radiation Production

undulator, radiation, linac, insertion-device

4060

C. Thongbai, N. Chaisueb, S. Rimjaem, J. Saisut, K. Thaijai-un
Chiang Mai University, Chiang Mai, Thailand
N. Kangrang
Chiang Mai University, PBP Research Facility, Chiang Mai, Thailand
P. Wichaisirimongkol
Chiang Mai University, Science and Technology Research Institute, Chiang Mai, Thailand

Funding: Chiang Mai University Research Fellowship Program
The goal of this research is to design and construct a compact electromagnetic undulator. This insertion device will be installed at the PBP-CMU-LINAC system of Chiang Mai University (CMU), Thailand, to produce THz radiation. The undulator magnet is designed by using 2D POISSON and 3D RADIA computer code to optimize the magnet dimensions. The width of iron pole (W) should be 12 mm. The length of iron pole (L) should be about 80 mm long and the thickness of return yoke (d) should be more than 10 mm. The magnet design, the in-house con-struction of the magnet, and the measurement results will be presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW051

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW052

Recent Magnetic Measurement Activities at NSLS-II Insertion Device Laboratory

undulator, vacuum, synchrotron, radiation

4063

M. Musardo, P.L. Cappadoro, O.V. Chubar, T.M. Corwin, H.C. Fernandes, D.A. Harder, D.A. Hidas, C.A. Kitegi, B.N. Kosciuk, W. Licciardi, J. Rank, C. Rhein, T. Tanabe
BNL, Upton, New York, USA

National Synchrotron Light Source II (NSLS-II) at Brookhaven National Laboratory (BNL) is a new 3 GeV third generation electron storage ring designated to provide extremely intense beams of X-ray, ultraviolet, and infrared light for basic and applied research. Insertion devices (IDs) play a significant role in achieving the high performance demands of NSLS-II. An accurate magnetic characterization and proper corrections of these devices are essential activities in the development of a state-of-the-art light source facility. This paper describes the results of the latest magnetic measurement activities at the NSLS-II ID laboratory.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW052

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW054

Cumulative Damage of Ultrafast Laser Pulses

laser, vacuum, experiment, site

4066

A. Hanuka, L. Schächter
Technion, Haifa, Israel
R.J. England, I.V. Makasyuk, K. Soong, K.P. Wootton, Z. Wu
SLAC, Menlo Park, California, USA

We demonstrate experimentally that damage threshold fluence (DTF) for fused silica changes with the number of femtosecond laser (10Hz 600Hz, 655 fs, 800nm) shots. Based on the experimental data we were able to develop a model which indicates that the change in DTF varies with number of shots logarithmically (ln^p) up to a critical value. Above this value, DTF approaches an asymptotic value. Both DTF for a single shot and the asymptotic value as well as the critical value where this happens are extrinsic parameters dependent on the configuration (repetition rate, pressure and geometry near or at the surface). Indications are that the power of this dependence (p) is an intrinsic parameter independent of the configuration.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW054

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW056

Fiber Laser Development for Dielectric Laser-driven Accelerator and Electron Beam Source

laser, target, radiation, acceleration

4070

H. Okamoto, S. Otsuki
The University of Tokyo, Tokyo, Japan
K. Koyama, M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
D. Satoh, T. Shibuya
TIT, Tokyo, Japan
M. Yoshida
KEK, Ibaraki, Japan

Our group is aiming for developing a table-top electronμbeam source, whose beam size is micro-meter order so that we can irradiate just the nuclei of cells (1μm) and observe the behavior in real time. This beam source will be realized by dielectric laser-driven accelerators(DLAs), which is expected to produce acceleration gradients of ~GV/m. To drive these accelerators, ultra-short pulse laser has to be incident to the structure*. We chose Ytterbium (Yb) fiber laser for generating and amplifying ultra-short laser pulse, which has high quantum efficiency and can easily pumped by LD, and is proper to produce ultra-short pulses because of its wide-band oscillation. We succeeded in getting ultra-short pulse (central wavelength: {1030} nm, average output: 10 W, pulse duration: ~10 ps, reputation rate: 84 MHz) from Yb fiber laser system. Also in order to make electron bunch by photo cathode, we then converted the obtained IR laser to UV of 258 nm (4ω) using BBO and LBO crystals. We are planning to amplify the pulses by Yb:YAG in future, which has its amplification band in {1030} nm.
* K. Koyama el al., "Design Of Photonic Crystal Accelerator For Radiation Biology," IPAC'12 Proceedings (2014)

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW056

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW057

Direct High Power Laser Diagnostic Technique on Focused Electron Bunch

laser, scattering, experiment, solenoid

4073

D. Igarashi, A. Endo, K. Sakaue, T. Takahashi, M. Washio
RISE, Tokyo, Japan

In laser produced plasma EUV source, high intensity pulse CO2 laser is essential for plasma generation. To achieve high conversion efﬁciency and stable EUV power, we would like to measure a laser proﬁle in the interaction point. However, there is no way to measure directly the laser profile of such a high intensity laser at the focus point. Therefore, we have been developing laser profiler based on laser Compton scattering(LCS). LCS signal by using focused electron beam shows 1D laser profile. 2D laser profile can be reconstructed by one-dimensional laser profiles from various angles using computer tomography. This method is suitable for high intensity laser, but very small spot size of electron beam is required. To obtain small spot size, we used S-band Cs-Te photocathode RF-Gun and specially designed solenoid lens at Waseda university. We already succeeded in observing minimum beam size of about 20 μm rms and this is adequate to scan the CO2 laser. In this conference, we will report the result of the laser Compton scattering with pulse CO2 laser, the preparatory experiment in measuring a metal wire cross section and the present progresses.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW057

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW058

Drive Laser System for the DC-SRF Photoinjector at Peking University

laser, SRF, optics, operation

4076

F.M. Liu, L.W. Feng, S. Huang, L. Lin, K.X. Liu, S.Y. Si, Zh.W. Wang, G. Zhao
PKU, Beijing, People's Republic of China

The DC-SRF photoinjector, developed at Peking University, uses Cs2Te as the photocathode and accordingly 266 nm laser is used as the drive laser. A drive laser sys-tem，which includes a 1064 nm laser oscillator, a four-stage amplifier, and second and fourth harmonic genera-tors, has been designed and applied successfully. To avoid the high average current electron beam from hitting the vacuum tube and causing safety problems, a laser pulse selector with an EO modulator has been designed and included into the laser drive system to reduce the repetition rate of electron pulses during the DC-SRF photoinjector commissioning. It can adjust the repetition rate of laser pulses from 81.25 kHz to 81.25 MHz. In this paper, we introduce the drive laser system and describe the laser pulse selector in detail.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW058

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW059

UV Pulse Shaping with a-BBO Crystals for the Photocathode RF Gun

laser, flattop, gun, optics

4079

D. Wang, W.-H. Huang, L.X. Yan
TUB, Beijing, People's Republic of China

Recently, manipulation with the drive laser plays a significant role in high brightness electron beam production by the photocathode RF gun. The method based on pulse stacking with birefringent crystal serials was tried to longitudinally shape ultraviolet laser pulse. Using four or five pieces of a-BBO crystals to stack an input UV pulse with appropriate initial duration into 16 or 32 sub-pulses to form quasi flattop UV laser pulse, which can be applied for emittance optimization of the electron beam based on the photocathode RF gun. Moreover, the negative slop of the energy transmittance of a-BBO serials is also revealed to be a passive stabilization mechanism for energy jitter reduction in the driving laser. With appropriate design of a-BBO serials, this method can fulfill the requirements for driving laser in a broad scope of applications such as x-ray FELs and high-power Terahertz(THz) radiation production.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW059

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOW060

Basic Design of Control System for IPM Linear Accelerator

controls, PLC, EPICS, linac

4082

S. Haghtalab, F. Abbasi
Shahid Beheshti University, Tehran, Iran
F. Ghasemi
NSTRI, Tehran, Iran
M. Jafarzadeh
ILSF, Tehran, Iran
M. Lamehi
IPM, Tehran, Iran

A control system has been designed for the commissioning of 10 MeV linear accelerator which is under construction in institute for research in fundamental science (IPM). The IPM e-Linac is a traveling wave accelerator consisting of 62 components in five major sections: control and safety, beam injection, radio frequency production and transmission, acceleration tube and target. The existence of a central control system for controlling and monitoring all parts of the machine is necessary. The aim of the system design is to implement a fast and reliable control system which is easy to operate and extensible for future upgrades and improvements. For this purpose, EPICS has been chosen as the main environment due to high performance and distributed structure. In this system, Siemens PLC is used as EPICS IOC and graphical designs will performed by CSS and WinCC. In this study, first we present a brief description of the IPM electron linear accelerator, and then architecture of the control system will be discussed.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW060

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOY001

Implementation of a New Ramp Computation Scheme for the Magnet Power Supplies at ELSA

controls, power-supply, extraction, injection

4085

D. Proft, W. Hillert
ELSA, Bonn, Germany

At the ELSA electron stretcher facility new power supply control units have been commissioned. These require a new software interface for set-point calculation based on the accelerator and timing model. Goal of the new scheme is a strict separation of the bidirectional ramp computation into an accelerator model dependent, a magnet dependent and a power supply dependent part. This introduces possible calibration/correction factors on each layer, thus allowing easy component replacement of the power supplies, the control units or even the magnets without the need for recalibration of the whole chain. In this contribution we will provide insights into the implementation of the new modeling scheme.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY001

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOY002

The New External Beamline for Detector Tests at ELSA

simulation, quadrupole, radiation, detector

4088

N. Heurich, F. Frommberger, P. Hänisch, W. Hillert
ELSA, Bonn, Germany

At the electron accelerator ELSA, a new external beam line has been constructed whose task is to provide a primary electron beam for detector tests. Using a slow resonance extraction method, it is possible to extract a quasi continuous electron beam with a maximum energy of 3.2 GeV to the test area. An external beam current of 100 pA to 1 fA can be realized. A further reduction of the beam current is envisaged as well. The beam width can be changed in both transverse directions from 1 mm to 8 mm. To dump and simultaneously measure the current of the electron beam behind the detector components a Faraday cup consisting of depleted uanium is used. The residual radiation leaving the cup is absorbed in a concrete casing. The radiation protection concept for the entire area of the new beamline was designed with the help of the Monte Carlo simulation program Fluka. In addition to the concrete casing, radiation protection walls were built to allow a safe working environment in the neighboring control room.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY002

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOY003

The Turn-key Control System for the ELI-NP Gamma Beam System

controls, EPICS, laser, timing

4091

S. Pioli, G. Di Pirro
INFN/LNF, Frascati (Roma), Italy
F. Amand, V.A. Isaev, A. Jesenko, A. Manojlovic, R. Modic, I. Mustac, G. Pajor
Cosylab, Ljubljana, Slovenia
B.G. Martlew, A. Oates
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

The new Gamma Beam System (GBS) under construction in Magurele (RO) by the consortium EuroGammas led by INFN, as part of the ELI-NP project, can provide gamma rays that open new possibilities for nuclear photonics and nuclear physics. In the ELI-GBS, gamma rays are produced by means of Compton back-scattering to get mono-chromaticity (0,1% bandwidth), a high flux (10¹³ photon/s the highest in the world), tunable directions and energies up to 19 MeV. Such gamma beam characteristic is obtained when a high-intensity laser collides a high-brightness electron-beam with energies up to 720 MeV. In order to increase the gamma beam flux, the electron beam operates at a repetition rate of 100 Hz in a multi-bunch mode: trains of 32 bunches, 16 ns apart, interact with the laser pulse recirculated 32 times through the interaction point. The EPICS Control System collects data from all sub-systems, constantly monitoring to ensure the safety of the ELI-GBS facility. This paper describes all the aspects of the ELI-GBS turn-key Control System, such as hardware integration, micro-bunches diagnostics, high level applications, the data network and the pico-second timing system.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY003

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOY024

Demagnetization of an Entire Accelerator Vault

cyclotron, TRIUMF, linac, power-supply

4143

T. Planche, R.A. Baartman, S.R. Koscielniak
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
G. Arias, T.C. LeRoss, K.K.S. Multani
UBC, Vancouver, B.C., Canada
D.A. Bissky Dziadyk
McGill University, Montréal,, Canada
T. Zuiderveen
University of Ottawa, Ottawa, Ontario, Canada

The ARIEL electron linac produced its first high-energy beam on 31 September 2014. Despite over 40 years of experience with ion beams, transporting electrons constituted a new challenge for TRIUMF. With good reason: the difference in rest mass makes electrons orders of magnitude more sensitive than ions to magnetic fields (for the same kinetic energy). In this paper we show how beam steering could have been seriously compromised by the remament field from the structural steel of the building, and how this issue was addressed using a technique developed to demagnetize steel-hull ships: we degaussed the entire accelerator vault.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY024

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOY026

Recent Challenges for the 1.5 GeV MAMI-C Accelerator at JGU Mainz

polarization, operation, microtron, experiment

4149

M. Dehn, K. Aulenbacher, H.-J. Kreidel, F. Nillius, B.S. Schlimme, V. Tioukine
IKP, Mainz, Germany

Funding: Work supported by DFG (CRC 1044) and the German federal state of Rhineland-Palatinate
The MAMI-C accelerator is a 1.5 GeV microtron cascade for up to 100 μA polarised electrons operating CW at Mainz University. Recent experiments required spin manipulations and beam energies not routinely supported by the accelerator. In particular, this required a spin orientation vertical to the accelerator plane and operation at beam energies which could not be achieved by the so far established methods. This paper describes the challenges to provide and to characterise the unusual modes of operation.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY026

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOY027

Commissioning Status of SuperKEKB Injector Linac

gun, emittance, linac, injection

4152

M. Satoh, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, Y. Enomoto, S. Fukuda, Y. Funakoshi, K. Furukawa, T. Higo, H. Honma, N. Iida, M. Ikeda, H. Iwase, H. Kaji, K. Kakihara, T. Kamitani, H. Katagiri, S. Kazama, M. Kikuchi, H. Koiso, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Mimashi, T. Miura, F. Miyahara, T. Mori, A. Morita, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, Y. Ohnishi, S. Ohsawa, F. Qiu, I. Satake, D. Satoh, Y. Seimiya, T. Shidara, A. Shirakawa, M. Suetake, H. Sugimoto, T. Suwada, M. Tanaka, M. Tawada, Y. Yano, K. Yokoyama, M. Yoshida, R. Zhang, X. Zhou
KEK, Ibaraki, Japan

The SuperKEKB main ring is currently being constructed for aiming at the peak luminosity of 8 x 10³⁵ cm^-2s⁻¹. The electron/positron injector linac upgrade is also going on for increasing the intensity of bunch charge with keeping the small emittance. The key upgrade issues are the construction of positron damping ring, a new positron capture system, and a low emittance photo-cathode rf electron source. The injector linac beam commissioning started in the October of 2013. In this paper, we report the present status and future plan of SuperKEKB injector commissioning.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY027

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOY028

Operational Status of HLS-II

operation, cavity, vacuum, storage-ring

4155

J.Y. Li, G. Huang, W. Wei, W. Xu, K. Xuan, Y.L. Yang, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

After a major renovation, the Hefei light source (HLS), renamed HLS_II, was brought into operation in the beginning of 2015. The operational result shows that the HLS-II not only provides much brighter synchrotron radiation beam for various users, but also shows much higher reliability than the old light source. This paper first gives an overview of the HLS-II. The overall performance of the light source is then summarized in this paper. Some measured key parameters of the light source, including emittance, orbit stability, beam lifetime and so on, are also presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY028

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOY047

Comprehensive Approach to Synchrotron Radiation Protection of NSLS-II

radiation, synchrotron, synchrotron-radiation, undulator

4211

S. Seletskiy, T.V. Shaftan
BNL, Upton, Long Island, New York, USA

To protect the NSLS-II Storage Ring components from possible damage from synchrotron radiation produced by insertion devices (IDs) and bending magnets (BMs) the Active Interlock System (AIS) keeps electron beam within the AI safe envelope (AIE) in the transverse phase space. The NSLS-II beamlines (BLs) and frontends (FEs) are designed under assumption that above certain safe beam current the ID synchrotron radiation (IDSR) fan is produced by the interlocked e-beam. In this paper we describe a new approach to defining the AIS parameters and settings, which significantly simplifies the process of the FE and BL design.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY047

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOY049

Helical Undulator as a Source of Spectromicroscopy Beamline of ILSF

polarization, undulator, photon, radiation

4217

S. Amiri, A. Gholampour, M. Jafarzadeh, M. Lamehi, J. Rahighi
ILSF, Tehran, Iran
M. Lamehi, J. Rahighi
IPM, Tehran, Iran

Regarding user requirements of spectromicroscopy beamline such as high flux, small spot size, linear and circular polarization light, a helical undulator have been chosen as a source for this beamline. Radiation properties of the source e.g. flux, flux density, brilliance, size and divergence of the photon beam, power, power density, angular distribution of power and flux on the axis of the undulator have been considered by theoretical formula and using SPECTRA code. At the circular polarization, the first harmonic covers the energies in the 100-1300 eV range and for the linear polarization energy ranges, 100-1000 eV and 1000-1500 eV, are provided by the first and third harmonics respectively. In the case of circular and linear polarization mode, maximum flux in the central cone for maximum undulator strength are 4.5 × 10¹⁶ (ph/s) at kX=ky=3.6 and 2.4 × 10¹⁶ (ph/s) at K=5.
* James A. Clarke, "The science and technology of undulators and wigglers", 2004.
** H. Onuki, P. Elleaume, "WIGGLERS UNDULATORs and their APLICATIONS", 2003.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY049

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOY050

Time Response of a Gridded X-ray Beam Ionization Chamber

ion, experiment, radiation, photon

4220

Y.H. Xu, Z.H. Sun
DongHua University, Songjiang, People's Republic of China
D.V. Campen, W.J. Corbett
SLAC, Menlo Park, California, USA
C.L. Li
East China University of Science and Technology, Shanghai, People's Republic of China
W.J. Zhang
University of Saskatchewan, Saskatoon, Canada

Recently, Quick-Scanning Extended X-ray Absorption Spectroscopy (QEXAS) has become an important tool for in-situ characterization of materials and measurement of associated electronic structure. In this case the time response of the ionization chamber affects the measurement resolution and therefore overall performance of the QEXAS system. Common parallel-plate ionization chambers have a step-response rise time of about 0.1 sec, which does not meet the requirements of QEXAS. To speed up the response, we constructed a gridded ionization chamber with variable bias voltage and optional background gas (N2 or He, respectively). To characterize the system we used a high-frequency beam chopper upstream of the ionization chamber and a high-speed, low-noise preamplifier to measure the step response of the chamber as a function of bias voltage and background gas conditions.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY050

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOY054

An External Synchronization of PHIL to a High Power Femtosecond Laser

laser, timing, gun, cavity

4228

N. ElKamchi, V. Chaumat
LAL, Orsay, France

The synchronization accuracy between laser systems and RF wave is a crucial ingredient for the successful operation of any particle accelerator based on photo-emission. In the case of ultra-short highly charged electron accelerator, the beam is highly sensitive to timing jitter. Thus, a high level of synchronization accuracy is needed. In this paper, we describe the current synchronization system of PHIL (electron accelerator at LAL), and a new approach to synchronize PHIL externally with a high power femtosecond laser (LASERIX) . The main goal of the experience is to design and study a compact way to obtain ultra-short electron bunches (few tens to few hundreds of femtoseconds) under high charge levels (hundred pC). We continue with a description of different modifications made on PHIL timing master to adapt it to external synchronization.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY054

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOY060

Four Beam Generation for Simultaneous Four-Hall Operation at CEBAF

laser, timing, space-charge, gun

4240

R. Kazimi, J.M. Grames, J. Hansknecht, A.S. Hofler, G.E. Lahti, T. E. Plawski, M. Poelker, R. Suleiman, Y.W. Wang
JLab, Newport News, Virginia, USA

Funding: Authored by JSA, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Gov't retains a non-exclusive, paidup, irrevocable, worldwide license to publish or reproduce this for U.S. Gov't purposes.
As part of the CEBAF 12 GeV upgrade at Jefferson Lab, a new experimental hall was added to the existing three halls. To deliver beam to all four halls simultaneous-ly, a new timing pattern for electron bunches is needed at the injector. This pattern change has consequences for the frequency of the lasers at the photogun, beam behavior in the chopping system, beam optics due to space charge, and setup procedures. We have successfully demonstrated this new pattern using the three existing drive lasers. The implementation of the full system will occur when the fourth laser is added and upgrades to the Low Level RF (LLRF) are complete. In this paper we explain the new bunch pattern, the challenges for setting and measuring the pattern such as 180° RF phase ambiguity, addition of the fourth laser to the laser table and LLRF upgrade.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY060

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRXBB01

Achieved Performance of an All X-band Photo-injector

gun, cathode, laser, emittance

4253

C. Limborg, C. Adolphsen, M.P. Dunning, R.K. Jobe, H. Li, D.J. McCormick, T.O. Raubenheimer, T. Vecchione, A.R. Vrielink, F.Y. Wang, S.P. Weathersby
SLAC, Menlo Park, California, USA

Funding: Work funded by DOE/SU Contract DE-AC02-76-SF00515
Building more compact accelerators to deliver high brightness electron beams for the generation of high flux, highly coherent radiation is a priority for the photon science community. A relatively straightforward reduction in footprint can be achieved by using high-gradient X-Band (11.4 GHz) RF technology. This talk presents the all X-band photo-injector facility at SLAC, covering the benefits of using this technology and highlighting the performance achieved.

Slides FRXBB01 [40.418 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-FRXBB01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRXCB01

Two Beam Wakefield Acceleration at Argonne Wakefield Accelerator Facility

wakefield, acceleration, experiment, laser

4258

W. Gai
ANL, Argonne, Illinois, USA

Structure based wakefield acceleration provides a viable approach capable of accelerating a sufficient electrons and positrons in a substantially high graident needed to meet the luminosity, efficiency, and cost requirements of a future linear collider. The short pulse Two Beam wakefield Acceleration (TBA) studied at the Argonne Wakefield Accelerator Facility is aimed to pave the way toward the next linear collider. Here we present the latest results including the 100MeV/m of the single stage TBA and the staged TBA in which a 0.5nC bunch gained equal amount of energy in two stages (~2.4 MeV per stage, corresponding to an average acceleration gradient ~70 MeV/m). The technique is scalable to a staged-acceleration at 200-300MeV/m by using a GeV-scale drive beam. Such a development will considerably reduce both cost and footprint of a future high-energy physics collider as well as future X-Ray light source.

Slides FRXCB01 [11.937 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-FRXCB01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)