IPAC2016 - List of Keywords (laser)

Paper	Title	Other Keywords	Page
MOXBA01	Beam Commissioning of PAL-XFEL	gun, undulator, linac, cathode	6
	J.H. Han PAL, Pohang, Kyungbuk, Republic of Korea
	The Pohang Accelerator Laboratory X-ray Free electron Laser (PAL-XFEL) project aims at the generation of X-ray FEL radiation for photon users. The machine consists of a 10 GeV normal-conducting S-band linear accelerator (linac) and two undulator beamlines initially. The hard X-ray beamline will provide FEL radiation between 0.6 and 0.1 nm or shorter. The soft X-ray line will provide FEL radiation between 4.5 and 1 nm. The linac and hard X-ray beamline construction was complete by the end of 2015. The installation of the soft X-ray line is ongoing. High power RF conditioning of the linac started in late autumn 2015. Beam commissioning of the linac started in April 2016. We report the beam commissioning status.
	Slides MOXBA01 [4.978 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOXBA01
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MOYBA01	Limits and Possibilities of Laser Wakefield Accelerators	electron, 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
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MOPMB003	Comparison of Coherent Smith-Purcell Radiation and Coherent Transition Radiation	radiation, electron, 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
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MOPMB010	Compton Polarimetry at ELSA - Beamline and Detector Optimization	photon, polarization, electron, 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
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MOPMB013	Time-resolved Spectral Observation of Coherent THz Pulses at DELTA	radiation, electron, 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
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MOPMB015	Technical Design Considerations About the SINBAD-ARES Linac	linac, gun, electron, 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
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MOPMB017	Design Issues for the Optical Transition Radiation Screens for theELI-NP Compton Gamma Source	radiation, electron, simulation, linac	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
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MOPMB018	Metrological Characterization of the Bunch Length Measurement by Means of a RF Deflector at the ELI-NP Compton Gamma source	linac, electron, simulation, 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
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MOPMB019	Quadrupole Scan Emittance Measurements for the ELI-NP Compton Gamma Source	emittance, electron, quadrupole, linac	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
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MOPMB026	Frequency and Time Domain Measurement of Coherent Transition Radiation	electron, 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
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MOPMB027	Beam Parameter Measurement After Relocation of S-Band Linear Accelerator	electron, linac, gun, simulation	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
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MOPMB029	Development Status of Linear Focal Cherenkov Ring Camera	electron, vacuum, 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
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MOPMB030	Development of an EO Sampling Method for THz Pulse Detection	radiation, polarization, electron, 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
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MOPMB040	Design of the Beam Diagnostics System for a New IR-FEL Facility at NSRL	diagnostics, FEL, cavity, emittance	181
	J.H. Wei, 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: Work supported by National Natural Science Foundation of China (21327901, 11105141, 11575181) A new IR-FEL has been commissioned at NSRL. This facility provides a final electron energy from 20 to 70 MeV, beam bunch with a macro-pulse length of 5~10 μs and a general micro-pulse repetition rate of 238 MHz, pulsed radiation with up to 100 mJ at about 0.3%~3% FWHM bandwidth. So a diagnostics system is necessary to monitor the performance of the bunch and the character of the FEL radiation, such as the beam position and profile, emittance, energy spread, laser intensity, etc. The beam diagnostics system mainly consists of Flags, a diagnostics beam line, BPMs, pop-in monitors and a FEL monitor system. This paper introduces the construction of this diagnostics system. Corresponding author: ylyang@ustc.edu.cn
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB040
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MOPMB054	A High Sensitivity Faraday Cup for Ultrashort Electron Bunches	electron, simulation, gun, 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
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MOPMR013	Development, Calibration and Application of New-generation Dissectors with Picosecond Temporal Resolution	electron, 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
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MOPMR026	Beam Instrumentation Performance during Commissioning of CERN's Linac-4 to 50 MeV and 100 MeV	emittance, linac, DTL, detector	293
	U. Raich, T. Hofmann, F. Roncarolo CERN, Geneva, Switzerland
	Linac-4, a 140 MeV H-linear accelerator is designed to replace the aging 50 MeV proton Linac. It will consist of an H-source and 45 keV LEBT, an RFQ and 3 MeV MEBT with a chopper, 3 drift tube linac (DTL) tanks accelerating the beam to 12, 30 and 50 Mev, cavity coupled structures (CCDTL) accelerating it to 100 MeV and a pi mode structure bringing it to its design energy of 160 MeV. This paper reports on the commissioning of the DTL and CCDTL with 2 dedicated temporary measurement lines, the first one adapted to the 12 MeV beam while the second one is dedicated to characterize the 50 MeV and the 100 MeV beams. The beam diagnostic devices used in these lines is described as well as results obtained.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR026
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MOPMR035	Bunch Length Measurements using a Transverse Deflecting Cavity on VELA	gun, cavity, electron, 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
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MOPMR038	Design and Simulation Studies of the Novel Beam Arrival Monitor Pickup at Daresbury Laboratory	pick-up, impedance, simulation, FEL	334
	A. Kalinin, S.P. Jamison, T.T. Thakker STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom R. Apsimon, G. Burt, A.C. Dexter Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
	We present the novel beam arrival monitor pickup design currently under construction at Daresbury Laboratory, Warrington, UK. The pickup consists of four flat electrodes in a transverse gap. CST Particle Studio simulations have been undertaken for the new pickup design as well as a pickup design from DESY, which is used as a reference for comparison. Simulation results have highlighted two advantages of the new pickup design over the DESY design; the signal bandwidth is 25 GHz, which is half that of the DESY design and the response slope is a factor of 1.6 greater. We discuss optimisation studies of the design parameters in order to maximise the response slope for bandwidths up to 50 GHz and present the final design of the pickup.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR038
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MOPMR045	High Resolution and Dynamic Range Characterisation of Beam Imaging Systems	optics, electron, 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
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MOPMR056	Single-shot THz Spectrometer for Measurement of RF Breakdown in mm-wave Accelerators	detector, vacuum, radiation, alignment	374
	S.V. Kutsaev, A.Y. Murokh, M. Ruelas, E.A. Savin, H.L. To RadiaBeam Systems, Santa Monica, California, USA M. Dal Forno, V.A. Dolgashev SLAC, Menlo Park, California, USA V. Goncharik Logicware Inc, New York, USA E.A. Savin MEPhI, Moscow, Russia
	Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics, under contract DE-SC0013684 We present a new instrument designed to detect RF pulse shortening caused by vacuum RF breakdown in mm-wave particle accelerators. RF breakdown limits the performance of high gradient RF accelerators. To understand the properties of these breakdowns, it is necessary to have diagnostics that reliably detect RF breakdowns. In X-band or S-band accelerators, RF breakdowns are detected by measuring RF pulse shortening, vacuum burst, or, if current monitors are available, spikes in the field-emitted currents. In mm-wave accelerators, all of these methods are difficult to use. In our experiments, we could not measure RF pulse shortening directly with a crystal detector because the RF pulse is very short'just a few nanoseconds'and changes in the measured signal were masked by RF amplitude jitter. To overcome this limitation, we built a single-shot spectrometer with a frequency range of 117-125 GHz and a resolution of 0.1 GHz. The spectrometer should be able to measure the widening of the spectrum caused by the shortening of nanosecond-long pulses. We present design considerations, first experimental results obtained at FACET, and planned future improvements for the spectrometer.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR056
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MOPMW036	Frequency Domain Simulations of Co-linear X-band Energy Booster (CXEB) RF Cavity Structures and Passive RF Components with ACE3P	cavity, electron, 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
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MOPOR037	Beam Halo Measurements using Vibrating Wire at the KOMAC	experiment, proton, target, neutron	680
	D. Choe, M. Chung, S.Y. Kim UNIST, Ulsan, Republic of Korea S.G. Arutunian, A.V. Margaryan ANSL, Yerevan, Armenia E.G. Lazareva YSU, Yerevan, Armenia
	In high-intensity particle accelerators, due to the fact that preventing beam loss plays a crucial role in con-ducting any experiments, it is important to measure and control the beam halo. Fortunately, it is feasible nowadays to measure the beam halo region thanks to the development of several sensitive beam scanning methods, including the vibrating wire technique. Since the vibrating wire is exceptionally sensitive to the heat deposition by the beam particles, it can be used to scanning the beam profile. This study will be concentrated on the precise beam profile measurement using the vibrating wire at the Korea Multi-Purpose Accelerator Complex (KOMAC) facility. First, we describe the best condition to construct beam profile measurement experiment. Finally, we present the results of the beam halo measurements performed with 20 MeV proton beam at the KOMAC facility
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR037
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MOPOW005	First Electron Beam Measurements on COXINEL	electron, 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
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MOPOW006	Planning and Controlling of the Cold Accelerator Sections Installation in XFEL	status, electron, 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
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MOPOW010	The Superconducting Soft X-ray Free-Electron Laser User Facility FLASH	FEL, photon, operation, electron	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
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MOPOW011	Operation of Free Electron Laser FLASH Driven by Short Electron Pulses	radiation, electron, undulator, simulation	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
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MOPOW014	Measurements of Ultrasmall Charges with MCP Detector in FLASH Accelerator	detector, electron, undulator, photon	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
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MOPOW015	Fermi Upgrade Plans	FEL, operation, electron, 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
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MOPOW016	Status of Design and Development of Delhi Light Source at IUAC, Delhi	electron, 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
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MOPOW017	Generation of GeV Photons from X-ray Free Electron Laser Oscillators	electron, photon, 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
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MOPOW019	Commissioning Status of the Extreme-Ultraviolet FEL Facility at SACLA	FEL, electron, undulator, booster	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
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MOPOW023	Proposal of an X-band Linearizer for Dalian Coherent Light Source	FEL, electron, 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
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MOPOW024	Harmonic Lasing Options for Dalian Coherent Light Source	FEL, radiation, electron, 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
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MOPOW027	Generation of Coherent Mode-locked Radiation in a Seeded Free Electron Laser	electron, radiation, FEL, 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
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MOPOW028	Research on Pulse Energy Fluctuation of a Cascaded High Gain Harmonic Generation Free Electron Laser	electron, FEL, 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
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MOPOW035	A Compact, Wavelength Tunable MW-THz FEL Amplifier	undulator, FEL, electron, 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
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MOPOW039	An Oscillator Configuration for Full Realization of Hard X-ray Free Electron Laser	electron, 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
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MOPOW045	Measurement of Advanced Dispersion-based Beam-tilt Correction	lattice, electron, FEL, photon	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
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MOPOW049	Implementation of a Corrugated-Plate Dechirping System for GeV Electron Beam at LCLS	FEL, electron, controls, 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
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MOPOY048	A Novel Approach in the One-Dimensional Phase Retrieval Problem and its Application to the Time Profile Reconstruction	electron, optics, FEL, 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
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TUZA01	Soft X-ray Free Electron Laser at SINAP	FEL, undulator, electron, 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
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TUZA02	Twin-bunch Two-colour FEL at LCLS	electron, 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
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TUOCA01	LCLS Bunch Compressor Configuration Study for Soft X-ray Operation	bunching, electron, 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
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TUOCA03	Commissioning of the European XFEL Injector	gun, emittance, controls, operation	1044
	F. Brinker DESY, Hamburg, Germany
	The European XFEL Injector consists of an L-Band RF photoinjector, a TESLA type 1.3 GHz module, a 3rd harmonic RF section, a laser heater and an extensive diagnostic section to determine projected and slice properties of the beam. The commissioning of the complete system has been started in December 2015 after several years of construction. We will report on commissioning results and persepctives for the later XFEL operation.
	Slides TUOCA03 [5.182 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOCA03
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TUXB01	High Power Radiation Sources using the Steady-state Microbunching Mechanism	radiation, storage-ring, FEL, focusing	1048
	A. Chao, E. Granados, X. Huang, D.F. Ratner SLAC, Menlo Park, California, USA H.W. Luo NTHU, Hsinchu, Taiwan
	The mechanism of steady-state microbunching (SSMB) was proposed for providing high power coherent radiation using electron storage rings. The mechanism follows closely the RF bunching in conventional storage rings, except that the energy modulation of by an RF system at a microwave wavelength is replaced by a seeded laser in an undulator at an optical wavelength. No FEL mechanism, and thus no FEL energy heating, is invoked. The basic idea is firstly to make the beam microbunched so that its radiation becomes coherent, and secondly to make the microbunching a steady state so that the coherent radiation is maintained at every turn. The combination of the high repetition rate of a storage ring and the enhanced radiation power by a factor of N (the number of electrons in the microbunches within one coherence length) opens the possibility as well as challenges of very high power SSMB sources. To explore its potential reach, we apply SSMB to the infrared, deep ultraviolet and EUV regions and estimate their respective power levels using SPEAR3 as example. Several variants of the SSMB schemes are discussed. A proof-of-principle configuration without an identified testbed is also suggested.
	Slides TUXB01 [1.602 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUXB01
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TUOBB03	CERN AWAKE Facility Readiness for First Beam	proton, plasma, electron, 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
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TUOCB02	Low Secondary Electron Yield of Laser Treated Surfaces of Copper, Aluminium and Stainless Steel	electron, 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
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TUPMB006	The Magnetic Measurement of Conventional Magnets for Free-Electron Laser Project of Chinese Academy of Engineering Physics	electron, dipole, collimation, FEL	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
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TUPMB011	Calculation and Analysis of the Magnetic Field of a Transverse Gradient Undulator	undulator, simulation, electron, FEL	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
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TUPMB013	PAL-XFEL Magnet Design and Magnetic Measurement	dipole, quadrupole, multipole, undulator	1136
	H.S. Suh, S.-H. Jeong, Y.-G. Jung, H.-S. Kang, D.E. Kim, I.S. Ko, H.-G. Lee, S.B. Lee, B.G. Oh, K.-H. Park PAL, Pohang, Kyungbuk, Republic of Korea
	We have designed and tested magnets for PAL-XFEL of 10GeV in Pohang, Korea. These magnets consist of 6 families of 52 dipole magnets, 11 families of 236 quadrupole magnets, and 4 families of 10⁸ corrector magnets. Two hall probe benches are used to measure the magnetic field. This paper reviews the main parameters of these magnets and the results of magnetic field measurements.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB013
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TUPMB038	Degradation of the Insulation of the LHC Main Dipole Cable when Exposed to High Temperatures	dipole, superconducting-magnet, operation, high-voltage	1186
	V. Raginel, B. Auchmann, D. Kleiven, R. Schmidt, A.P. Verweij, D. Wollmann CERN, Geneva, Switzerland
	Funding: Research supported by the High Luminosity LHC project The energy stored in the LHC beams is substantial and requires a complex machine protection system to protect the equipment. Despite efficient beam absorbers, several failure modes lead to some limited beam impact on superconducting magnets. Thus it is required to understand the damage mechanisms and limits of superconducting magnets due to instantaneous beam impact. This becomes even more important due to the future upgrade of CERNs injector chain for the LHC that will lead to an increase of the beam brightness. A roadmap to perform damage tests on magnet parts has been presented previously. The polyimide insulation of the superconducting cable is identified as one of the critical elements of the magnet. In this contribution, the experimental setup to measure the insulation degradation of LHC main dipole cables due to exposure to high temperature is described. Compressed stacks of insulated Nb-Ti cables have been exposed to a heat treatment within an Argon atmosphere. After each heat treatment, high-voltage measurements verified the dielectric strength of the insulation. The results of this experiment provide an upper damage limit of superconducting magnets due to beam impact. Experimental Setups to Determine the Damage Limit of Superconducting Magnets for Instantaneous Beam Losses, V. Raginel et al, IPAC'15
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB038
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TUPMR030	Progress on RFQ Fabrication for RISP Accelerator	rfq, vacuum, alignment, cavity	1308
	B.-S. Park, B.H. Choi, I.S. Hong IBS, Daejeon, Republic of Korea
	The 81.25MHz Radio Frequency Quadrupole(RFQ), which was designed to accelerate various ion beams from the energy of 10 keV/u to 500 keV/u, is under development for the Rare Isotope Science Project(RISP). The 5 meter long RFQ consists of 9 sections and the total weight is roughly 16 tons. Each sections of RFQ aligned and installed by using a laser tracker on a supporter system. In this paper, the fabrication status of the RISP RFQ and the scheme of installation were described in detail. This work was supported by the RISP of IBS funded by the Ministry of Science, ICT and Future Planning(MSIP) and the National Research Foundation(NRF) of Korea(2013M7A1A1075764).
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR030
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TUPMR052	Commissioning Preparation of the AWAKE Proton Beam Line	proton, plasma, experiment, extraction	1374
	J.S. Schmidt, B. Biskup, C. Bracco, B. Goddard, R. Gorbonosov, M. Gourber-Pace, E. Gschwendtner, L.K. Jensen, O.R. Jones, V. Kain, S. Mazzoni, M. Meddahi CERN, Geneva, Switzerland
	The AWAKE experiment at CERN will use a proton bunch with an momentum of 400 GeV/c from the SPS to drive large amplitude wakefields in a plasma. This will require a ~830 m long transfer line from the SPS to the experiment. The prepa- rations for the beam commissioning of the AWAKE proton transfer line are presented in this paper. They include the detailed planning of the commissioning steps, controls and beam instrumentation specifications as well as operational tools, which are developed for the steering and monitoring of the beam line. The installation of the transfer line has been finished and first beam is planned in summer 2016.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR052
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TUPMW003	Integration, Configuration and Coordination: from Project to Reality, at CERN	ECR, database, survey, status	1407
	M. Barberan Marin, S. Bartolome-Jimenez, M. Bernardini, T.W. Birtwistle, S. Chemli, J.-P. Corso, J. Coupard, K. Foraz, S. Grillot, Y. Muttoni, A.-L. Perrot CERN, Geneva, Switzerland
	The rigorous process in place at CERN to approve and follow-up the implementation of any modification of the LHC machine and its Injectors is presented in this paper. Our methodology implies the support of three teams, in charge of the configuration management, the scheduling and safety coordination, and the 3D integration studies. At each stage of the project the support of the three teams evolves, to provide the adequate support in the preparation phase and during the technical stops and long shutdowns. The formal roles and the processes used to govern the interaction of the Integration, Configuration and Coordination teams, and their relation to the project teams during the preparation and implementation phases, for activities to be performed in LHC and its injector chain are described and discussed.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW003
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TUPMY015	Ultrafast Electron Guns for the Efficient Acceleration using Single-Cycle THz Pulses	electron, gun, acceleration, 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
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TUPMY016	Design of a Collection and Selection System for High Energy Laser-driven Ion Beams	ion, dipole, quadrupole, proton	1581
	F. Schillaci, L. Allegra, A. Amato, L. Andò, G.A.P. Cirrone, M. Costa, G. Cuttone, G. De Luca, G. Gallo, J. Pipek, F. Romano INFN/LNS, Catania, Italy G. Korn, D. Margarone, V. Scuderi ELI-BEAMS, Prague, Czech Republic M. Maggiore INFN/LNL, Legnaro (PD), Italy
	Funding: ELI-Beamlines Contract n.S14-187, LaserGen(CZ.1.07/2.3.00/30.0057), Ministry of Education of Czech Rep.(reg. No.CZ.1.05/1.1.00/02.0061), the FZU, AVCR, v.v.i and the project financed by ESF and Czech Rep. Laser-target acceleration represents a very promising alternative to conventional accelerators for several potential applications, from the nuclear physics to the medical ones. However, some extreme features, not suitable for multidisciplinary applications, as the wide energy and angular spreads are typical of optically accelerated ion beams. Therefore, beyond the improvements at the laser-target interaction level, a lot of efforts have been recently devoted to the development of specific beam-transport devices in order to obtain controlled and reproducible output beams. In this framework, a three years contract has been signed between INFN-LNS (IT) and Eli-Beamlines-IoP (CZ) to provide the design and the realization of a complete transport beam-line, named ELIMED, dedicated to the transport, diagnostics and dosimetry of laser-driven ion beams. The transport devices will be composed by a set of super-strong permanent magnet quadrupoles able to collect and focus laser driven ions up to 70MeV/u, and a magnetic chicane made of conventional electromagnetic dipole to select particles within a narrow energy range. Here, the design and development of these magnetic systems is described.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY016
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TUPMY017	Laser Driven Dielectric Accelerator in the Non-relativistic Energy Region	acceleration, electron, 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
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TUPMY018	Recent Progress of Proton Acceleration at Peking University	electron, 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
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TUPMY019	CLAPA Proton Beam Line in Peking University	proton, target, plasma, ion	1592
	J.G. Zhu, J.E. Chen, C. Lin, H.Y. Lu, W.J. Ma, L. Tao, X.Q. Yan, K. Zhu PKU, Beijing, People's Republic of China
	Comparing with the conventional accelerator, the laser plasma accelerator can accelerate ions more effectively and greatly reduce the scale and cost. A laser accelerator− Compact Laser Plasma Accelerator (CLAPA) is being built at Institute of Heavy Ion physics of Peking University. According to the beam parameters from proof of principle experiments and theoretical simulations, we design the beam line for ions transport which is being built now and in the near future we will carry out experimental study with it. The beam line is mainly constituted by quadrupole and analyzing magnets . The quadrupole triplet lens collects protons generated from the target, while the analyzing magnet system will choose the protons with proper energy. The transport is simulated by program TRACK. The beam line is designed to deliver proton beam with the energy of 1~ 40MeV, energy spread of ±1% and 106-8 protons per pulse to satisfy the requirement of different experiments. The transmission efficiency is about 94% when the energy spread is ±1%.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY019
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TUPMY023	Advanced Gabor Lens Lattice for Laser Driven Hadron Therapy and Other Applications	lattice, collimation, ion, cavity	1595
	J.K. Pozimski, M. Aslaninejad, P.A. Posocco Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	Funding: Funding was provided by the Imperial Confidence in Concept scheme. The application of laser accelerated ion beams in hadron therapy requires a beam optics with unique features. Due to the spectral and spatial distribution of laser accelerated protons a compact ion optical system with therapy applications, based on Gabor space charge lenses for collecting, focusing and energy filtering the laser produced proton beam, has significant advantages compared with other setups. While a passive momentum selection could improve already the usability of laser driven hadron, we show that an advanced lattice utilizing additional RF cavities not only will deliver a momentum spread smaller than conventional accelerators, but also will increases the dose delivered. Furthermore, a possible near term application in the field of radio nuclide production is presented.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY023
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TUPMY026	Electron Beam Generation and Injection From a Pyroelectric Crystal Array	acceleration, electron, 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
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TUPMY028	Ultra-high Gradient Acceleration in Nano-crystal Channels	electron, plasma, 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
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TUPMY030	Measurements of Transmitted Electron Beam Extinction through Si Crystal Membranes	electron, emittance, scattering, 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
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TUPMY036	Drive Generation and Propagation Studies for the Two Beam Acceleration Experiment at the Argonne Wakefield Accelerator	kicker, simulation, power-supply, wakefield	1629
	N.R. Neveu, M.E. Conde, D.S. Doran, W. Gai, G. Ha, C.-J. Jing, W. Liu, J.G. Power, D. Wang, C. Whiteford, E.E. Wisniewski ANL, Argonne, Illinois, USA S.P. Antipov, C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA G. Ha POSTECH, Pohang, Kyungbuk, Republic of Korea N.R. Neveu IIT, Chicago, Illinois, USA D. Wang TUB, Beijing, People's Republic of China
	Funding: Work supported by by the U.S. Department of Energy under contract No. DE-AC02-06CH11357. Simplified staging in a two beam accelerator (TBA) has been accomplished at the Argonne Wakefield Accelerator (AWA) facility. This layout consists of a drive beamline and witness beamline operating synchronously. The drive photoinjector linac produces a 70 MeV drive bunch train of eight electron bunches (charge per bunch between 5-40 nC) that pass through decelerating structures in each TBA stage. The witness linac produces an 8 MeV witness bunch that passes through the accelerating structures in each TBA stage. Recent effort has been focused on improving the uniformity of the UV laser pulses that generate the bunch trains. Current work at the AWA is focused on the transition from simplified staging to full staging. A kicker will be designed and installed to direct bunch trains to one TBA stage only. Preliminary calculations and simulation results are presented.
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TUPMY041	Delivery Status of the ELI-NP Gamma Beam System	gun, solenoid, linac, vacuum	1635
	S. Tomassini, D. Alesini, A. Battisti, R. Boni, F. Cioeta, A. Delle Piane, E. Di Pasquale, G. Di Pirro, A. Falone, A. Gallo, S.I. Incremona, V.L. Lollo, A. Mostacci, S. Pioli, R. Ricci, U. Rotundo, A. Stella, C. Vaccarezza, A. Vannozzi, A. Variola INFN/LNF, Frascati (Roma), Italy A. Bacci, D.T. Palmer, L. Serafini Istituto Nazionale di Fisica Nucleare, Milano, Italy N. Bliss STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom F. Cardelli INFN-Roma1, Rome, Italy K. Cassou, Z.F. Zomer LAL, Orsay, France G. D'Auria Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy A. Giribono, V. Pettinacci INFN-Roma, Roma, Italy C. Hill STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom L. Palumbo Rome University La Sapienza, Roma, Italy L. Piersanti University of Rome La Sapienza, Rome, Italy
	The ELI-NP GBS is a high intensity and monochromatic gamma source under construction in Magurele (Romania). The design and construction of the Gamma Beam System complex as well as the integration of the technical plants and the commissioning of the overall facility, was awarded to the Eurogammas Consortium in March 2014. The delivery of the facility has been planned in for 4 stages and the first one was fulfilled in October 31st 2015. The engineering aspects related to the delivery stage 1 are presented.
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TUPOR019	RF Injector Beam Dynamics Optimization and Injected Beam Energy Constraints for LCLS-II	cavity, emittance, electron, 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
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TUPOW004	Status of the STAR Project	electron, 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
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TUPOW008	Generation of Short Bunch Electron Beam from Compact Accelerator for Terahertz Radiation	electron, 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.
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TUPOW025	First Beam Test of the High Brightness Photo-injector at NSRRC	gun, linac, electron, 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.
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TUPOW027	Model Independent Analysis of Beam Jitter on VELA	cathode, timing, distributed, gun	1806
	J.K. Jones, K.D. Dumbell, A.J. Moss, E.W. Snedden STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	The Versatile Electron Linear Accelerator (VELA) is a facility designed to provide high quality electron beams for accelerator systems development, as well as industrial and scientific applications. A key performance indicator for many applications is the inherent beam jitter on the machine (temporal, momentum and positional). Analysis of this beam jitter indicates that there are several independent mechanisms driving the beam motion. We use model independent analysis to correlate various dominant modes of beam jitter and compare them to simulations. We also compare the dominant modes before and after intervention work on the DLLRF timing system, and determine the relevant changes in beam motion.
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TUPOW028	Comparison of Model vs. Reality for VELA	gun, cathode, simulation, solenoid	1810
	M.S. Toplis, J.W. McKenzie, B.D. Muratori, D.J. Scott, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	The Versatile Electron Linear Accelerator (VELA) is a facility designed to provide a high quality electron beam for accelerator systems development, as well as industrial and scientific applications. Currently, the RF gun can deliver short bunches, of the order of 100 fs to a few ps, with a charge of up to 250 pC, at the longer bunch lengths, and up to 4.5 MeV/c beam momentum. A model for the injector has been developed in ASTRA, together with a suite of scripts to create scans of the available parameters around an empirically found arbitrarily optimal working point. The space of parameters consists of everything that can be changed in the control room, and ranges from bunch charge to laser spot size on the cathode, together with all magnet settings where and if necessary. The various scans facilitate the task of identifying where exactly the accelerator is in terms of parameters and trends. Initial comparisons of screen images are made between the model and reality. Ultimately, the goal of the model is to robustly and repeatably establish a desired operating setup on a daily basis from an unknown switch on condition.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW028
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TUPOW036	Recent Developments and Operational Status of the Compact ERL at KEK	operation, linac, emittance, gun	1835
	T. Obina, M. Adachi, S. Adachi, T. Akagi, M. Akemoto, D.A. Arakawa, S. Araki, S. Asaoka, M. Egi, K. Enami, K. Endo, S. Fukuda, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, K. Hozumi, A. Ishii, X.J. Jin, E. Kako, Y. Kamiya, H. Katagiri, R. Kato, H. Kawata, Y. Kobayashi, Y. Kojima, Y. Kondo, T. Konomi, A. Kosuge, T. Kume, T. Matsumoto, H. Matsumura, H. Matsushita, S. Michizono, T. Miura, T. Miyajima, H. Miyauchi, S. Nagahashi, H. Nakai, H. Nakajima, N. Nakamura, K. Nakanishi, K. Nakao, K.N. Nigorikawa, T. Nogami, S. Noguchi, S. Nozawa, T. Ozaki, F. Qiu, H. Sagehashi, H. Sakai, S. Sakanaka, S. Sasaki, K. Satoh, Y. Seimiya, T. Shidara, M. Shimada, K. Shinoe, T. Shioya, T. Shishido, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, T. Takenaka, O. Tanaka, Y. Tanimoto, N. Terunuma, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, J. Urakawa, K. Watanabe, M. Yamamoto, N. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida KEK, Ibaraki, Japan R. Hajima, M. Mori, R. Nagai, N. Nishimori, M. Sawamura, T. Shizuma QST, Tokai, Japan M. Kuriki Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
	The Compact Energy Recovery Linac (cERL) at KEK is a test accelerator in order to develop key components to realize remarkable ERL performance as a future light source. After the beam commissioning in December 2013, the legal current limit has been increased step-by-step like 1 uA, 10 uA, and 100 uA. Survey for the source of beam losses has been conducted in each step, and the study on beam dynamics and tuning has also been carried out. As a next step, 1 mA operation is scheduled in February 2016. In parallel to the increase in beam current, a laser Compton scattering (LCS) system which can provide high-flux X-ray to a beamline has been successfully commissioned. We report recent progress in various kinds of beam tuning: improvement of electron gun performance, high bunch charge operation, mitigation of beam losses, LCS optics tuning and bunch compression for THz radiation.
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TUPOW041	Optimization Studies for the Beam Dynamic in the RF Linac of the ELI-NP Gamma Beam System	electron, 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.
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TUPOW042	Expected Gamma Spectra at ELI-NP-GBS	photon, polarization, electron, 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.
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TUPOW046	Development and Upgrade Plan of an X-ray Source Based on Laser Compton Scattering in Laser Undulator Compact X-ray Source(LUCX)	electron, 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.
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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	electron, 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.
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TUPOW052	LLNL Laser-Compton X-ray Characterization	electron, 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.
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TUPOW053	Measurement of Terahertz Generation in a Metallic, Corrugated Beam Pipe	radiation, electron, experiment, dipole	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
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TUPOW054	Characterization of a Sub-THz Radiation Source Based on a 3 MeV Electron Beam and Future Plans	electron, radiation, experiment, quadrupole	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
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TUPOY003	Novel Approach to Utilize Proton Beams from High Power Laser Accelerators for Therapy	proton, acceleration, target, radiation	1905
	U. Masood, M. Baumann, W. Enghardt, L. Karsch, J. Pawelke, S. Schürer OncoRay, Dresden, Germany M. Baumann German Cancer Research Center (DKFZ), Heidelberg, Germany M. Baumann German Cancer Consortium (DKTK), Dresden, Germany T.E. Cowan, U. Schramm Technische Universität Dresden, Dresden, Germany T.E. Cowan, W. Enghardt, T. Herrmannsdoerfer, J. Pawelke, U. Schramm HZDR, Dresden, Germany K.M. Hofmann, J.J. Wilkens Technische Universität München, Klinikum rechts der Isar & Physics Department, Munich, Germany F. Kroll Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany
	Funding: Supported by German BMBF, nos. 03Z1N511 and 03Z1O511 & DFG cluster of excellence MAP. Protons provide superior radiotherapy benefits to patients, but immense size and cost of the system limits it to only few centers worldwide. Proton acceleration on μm scale via high intensity laser is promising to reduce size and costs of proton therapy, but associated beamlines are still big and massive. Also, in contrast to conventionally accelerated quasi-continuous mono-energetic pencil beams, laser-driven beams have distinct beam properties, i.e. ultra-intense pico-sec bunches with large energy spread and large divergences, and with low repetition rate. With new lasers with petawatt power, protons with therapy related energies could be achieved, however, the beam properties make it challenging to adapt them directly for medical applications. We will present our compact beamline solution including energy selection and divergence control, and a new beam scanning and dose delivery system with specialized 3D treatment planning system for laser-driven proton beams. The beamline is based on high field iron-less pulsed magnets and about three times smaller than the conventional systems, and can provide high quality clinical treatment plans. U. Masood et al, Applied Phys B, 117(1):41-52, 2014 ** K.M. Hofmann et al, Medical Physics, 42(9):5120-5129, 2015
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TUPOY027	Beam Dynamics Studies into Grating-based Dielectric Laser-driven Accelerators	electron, 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.
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MOXBA01

Beam Commissioning of PAL-XFEL

gun, undulator, linac, cathode

6

J.H. Han
PAL, Pohang, Kyungbuk, Republic of Korea

The Pohang Accelerator Laboratory X-ray Free electron Laser (PAL-XFEL) project aims at the generation of X-ray FEL radiation for photon users. The machine consists of a 10 GeV normal-conducting S-band linear accelerator (linac) and two undulator beamlines initially. The hard X-ray beamline will provide FEL radiation between 0.6 and 0.1 nm or shorter. The soft X-ray line will provide FEL radiation between 4.5 and 1 nm. The linac and hard X-ray beamline construction was complete by the end of 2015. The installation of the soft X-ray line is ongoing. High power RF conditioning of the linac started in late autumn 2015. Beam commissioning of the linac started in April 2016. We report the beam commissioning status.

Slides MOXBA01 [4.978 MB]

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MOYBA01

Limits and Possibilities of Laser Wakefield Accelerators

electron, 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]

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MOPMB003

Comparison of Coherent Smith-Purcell Radiation and Coherent Transition Radiation

radiation, electron, 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.

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MOPMB010

Compton Polarimetry at ELSA - Beamline and Detector Optimization

photon, polarization, electron, 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.

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MOPMB013

Time-resolved Spectral Observation of Coherent THz Pulses at DELTA

radiation, electron, 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.

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MOPMB015

Technical Design Considerations About the SINBAD-ARES Linac

linac, gun, electron, 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.

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MOPMB017

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

radiation, electron, simulation, linac

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.

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MOPMB018

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

linac, electron, simulation, 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).

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MOPMB019

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

emittance, electron, quadrupole, linac

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.

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MOPMB026

Frequency and Time Domain Measurement of Coherent Transition Radiation

electron, 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).

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MOPMB027

Beam Parameter Measurement After Relocation of S-Band Linear Accelerator

electron, linac, gun, simulation

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.

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MOPMB029

Development Status of Linear Focal Cherenkov Ring Camera

electron, vacuum, 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.

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MOPMB030

Development of an EO Sampling Method for THz Pulse Detection

radiation, polarization, electron, 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.

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MOPMB040

Design of the Beam Diagnostics System for a New IR-FEL Facility at NSRL

diagnostics, FEL, cavity, emittance

181

J.H. Wei, 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: Work supported by National Natural Science Foundation of China (21327901, 11105141, 11575181)
A new IR-FEL has been commissioned at NSRL. This facility provides a final electron energy from 20 to 70 MeV, beam bunch with a macro-pulse length of 5~10 μs and a general micro-pulse repetition rate of 238 MHz, pulsed radiation with up to 100 mJ at about 0.3%~3% FWHM bandwidth. So a diagnostics system is necessary to monitor the performance of the bunch and the character of the FEL radiation, such as the beam position and profile, emittance, energy spread, laser intensity, etc. The beam diagnostics system mainly consists of Flags, a diagnostics beam line, BPMs, pop-in monitors and a FEL monitor system. This paper introduces the construction of this diagnostics system.
Corresponding author: ylyang@ustc.edu.cn

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MOPMB054

A High Sensitivity Faraday Cup for Ultrashort Electron Bunches

electron, simulation, gun, 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.

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MOPMR013

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

electron, 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

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MOPMR026

Beam Instrumentation Performance during Commissioning of CERN's Linac-4 to 50 MeV and 100 MeV

emittance, linac, DTL, detector

293

U. Raich, T. Hofmann, F. Roncarolo
CERN, Geneva, Switzerland

Linac-4, a 140 MeV H-linear accelerator is designed to replace the aging 50 MeV proton Linac. It will consist of an H-source and 45 keV LEBT, an RFQ and 3 MeV MEBT with a chopper, 3 drift tube linac (DTL) tanks accelerating the beam to 12, 30 and 50 Mev, cavity coupled structures (CCDTL) accelerating it to 100 MeV and a pi mode structure bringing it to its design energy of 160 MeV. This paper reports on the commissioning of the DTL and CCDTL with 2 dedicated temporary measurement lines, the first one adapted to the 12 MeV beam while the second one is dedicated to characterize the 50 MeV and the 100 MeV beams. The beam diagnostic devices used in these lines is described as well as results obtained.

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MOPMR035

Bunch Length Measurements using a Transverse Deflecting Cavity on VELA

gun, cavity, electron, 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.

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MOPMR038

Design and Simulation Studies of the Novel Beam Arrival Monitor Pickup at Daresbury Laboratory

pick-up, impedance, simulation, FEL

334

A. Kalinin, S.P. Jamison, T.T. Thakker
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
R. Apsimon, G. Burt, A.C. Dexter
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom

We present the novel beam arrival monitor pickup design currently under construction at Daresbury Laboratory, Warrington, UK. The pickup consists of four flat electrodes in a transverse gap. CST Particle Studio simulations have been undertaken for the new pickup design as well as a pickup design from DESY, which is used as a reference for comparison. Simulation results have highlighted two advantages of the new pickup design over the DESY design; the signal bandwidth is 25 GHz, which is half that of the DESY design and the response slope is a factor of 1.6 greater. We discuss optimisation studies of the design parameters in order to maximise the response slope for bandwidths up to 50 GHz and present the final design of the pickup.

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MOPMR045

High Resolution and Dynamic Range Characterisation of Beam Imaging Systems

optics, electron, 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.

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MOPMR056

Single-shot THz Spectrometer for Measurement of RF Breakdown in mm-wave Accelerators

detector, vacuum, radiation, alignment

374

S.V. Kutsaev, A.Y. Murokh, M. Ruelas, E.A. Savin, H.L. To
RadiaBeam Systems, Santa Monica, California, USA
M. Dal Forno, V.A. Dolgashev
SLAC, Menlo Park, California, USA
V. Goncharik
Logicware Inc, New York, USA
E.A. Savin
MEPhI, Moscow, Russia

Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics, under contract DE-SC0013684
We present a new instrument designed to detect RF pulse shortening caused by vacuum RF breakdown in mm-wave particle accelerators. RF breakdown limits the performance of high gradient RF accelerators. To understand the properties of these breakdowns, it is necessary to have diagnostics that reliably detect RF breakdowns. In X-band or S-band accelerators, RF breakdowns are detected by measuring RF pulse shortening, vacuum burst, or, if current monitors are available, spikes in the field-emitted currents. In mm-wave accelerators, all of these methods are difficult to use. In our experiments, we could not measure RF pulse shortening directly with a crystal detector because the RF pulse is very short'just a few nanoseconds'and changes in the measured signal were masked by RF amplitude jitter. To overcome this limitation, we built a single-shot spectrometer with a frequency range of 117-125 GHz and a resolution of 0.1 GHz. The spectrometer should be able to measure the widening of the spectrum caused by the shortening of nanosecond-long pulses. We present design considerations, first experimental results obtained at FACET, and planned future improvements for the spectrometer.

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MOPMW036

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

cavity, electron, 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.

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MOPOR037

Beam Halo Measurements using Vibrating Wire at the KOMAC

experiment, proton, target, neutron

680

D. Choe, M. Chung, S.Y. Kim
UNIST, Ulsan, Republic of Korea
S.G. Arutunian, A.V. Margaryan
ANSL, Yerevan, Armenia
E.G. Lazareva
YSU, Yerevan, Armenia

In high-intensity particle accelerators, due to the fact that preventing beam loss plays a crucial role in con-ducting any experiments, it is important to measure and control the beam halo. Fortunately, it is feasible nowadays to measure the beam halo region thanks to the development of several sensitive beam scanning methods, including the vibrating wire technique. Since the vibrating wire is exceptionally sensitive to the heat deposition by the beam particles, it can be used to scanning the beam profile. This study will be concentrated on the precise beam profile measurement using the vibrating wire at the Korea Multi-Purpose Accelerator Complex (KOMAC) facility. First, we describe the best condition to construct beam profile measurement experiment. Finally, we present the results of the beam halo measurements performed with 20 MeV proton beam at the KOMAC facility

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MOPOW005

First Electron Beam Measurements on COXINEL

electron, 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.

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MOPOW006

Planning and Controlling of the Cold Accelerator Sections Installation in XFEL

status, electron, 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.

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MOPOW010

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

FEL, photon, operation, electron

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.

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MOPOW011

Operation of Free Electron Laser FLASH Driven by Short Electron Pulses

radiation, electron, undulator, simulation

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.

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MOPOW014

Measurements of Ultrasmall Charges with MCP Detector in FLASH Accelerator

detector, electron, undulator, photon

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.

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MOPOW015

Fermi Upgrade Plans

FEL, operation, electron, 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.

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MOPOW016

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

electron, 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.

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MOPOW017

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

electron, photon, 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.

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MOPOW019

Commissioning Status of the Extreme-Ultraviolet FEL Facility at SACLA

FEL, electron, undulator, booster

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.

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MOPOW023

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

FEL, electron, 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.

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MOPOW024

Harmonic Lasing Options for Dalian Coherent Light Source

FEL, radiation, electron, 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.

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MOPOW027

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

electron, radiation, FEL, 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.

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MOPOW028

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

electron, FEL, 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.

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MOPOW035

A Compact, Wavelength Tunable MW-THz FEL Amplifier

undulator, FEL, electron, 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).

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MOPOW039

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

electron, 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

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MOPOW045

Measurement of Advanced Dispersion-based Beam-tilt Correction

lattice, electron, FEL, photon

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.

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MOPOW049

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

FEL, electron, controls, 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.

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MOPOY048

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

electron, optics, FEL, 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.

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TUZA01

Soft X-ray Free Electron Laser at SINAP

FEL, undulator, electron, 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]

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TUZA02

Twin-bunch Two-colour FEL at LCLS

electron, 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]

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TUOCA01

LCLS Bunch Compressor Configuration Study for Soft X-ray Operation

bunching, electron, 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]

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TUOCA03

Commissioning of the European XFEL Injector

gun, emittance, controls, operation

1044

F. Brinker
DESY, Hamburg, Germany

The European XFEL Injector consists of an L-Band RF photoinjector, a TESLA type 1.3 GHz module, a 3rd harmonic RF section, a laser heater and an extensive diagnostic section to determine projected and slice properties of the beam. The commissioning of the complete system has been started in December 2015 after several years of construction. We will report on commissioning results and persepctives for the later XFEL operation.

Slides TUOCA03 [5.182 MB]

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TUXB01

High Power Radiation Sources using the Steady-state Microbunching Mechanism

radiation, storage-ring, FEL, focusing

1048

A. Chao, E. Granados, X. Huang, D.F. Ratner
SLAC, Menlo Park, California, USA
H.W. Luo
NTHU, Hsinchu, Taiwan

The mechanism of steady-state microbunching (SSMB) was proposed for providing high power coherent radiation using electron storage rings. The mechanism follows closely the RF bunching in conventional storage rings, except that the energy modulation of by an RF system at a microwave wavelength is replaced by a seeded laser in an undulator at an optical wavelength. No FEL mechanism, and thus no FEL energy heating, is invoked. The basic idea is firstly to make the beam microbunched so that its radiation becomes coherent, and secondly to make the microbunching a steady state so that the coherent radiation is maintained at every turn. The combination of the high repetition rate of a storage ring and the enhanced radiation power by a factor of N (the number of electrons in the microbunches within one coherence length) opens the possibility as well as challenges of very high power SSMB sources. To explore its potential reach, we apply SSMB to the infrared, deep ultraviolet and EUV regions and estimate their respective power levels using SPEAR3 as example. Several variants of the SSMB schemes are discussed. A proof-of-principle configuration without an identified testbed is also suggested.

Slides TUXB01 [1.602 MB]

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TUOBB03

CERN AWAKE Facility Readiness for First Beam

proton, plasma, electron, 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]

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TUOCB02

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

electron, 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]

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TUPMB006

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

electron, dipole, collimation, FEL

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.

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TUPMB011

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

undulator, simulation, electron, FEL

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.

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TUPMB013

PAL-XFEL Magnet Design and Magnetic Measurement

dipole, quadrupole, multipole, undulator

1136

H.S. Suh, S.-H. Jeong, Y.-G. Jung, H.-S. Kang, D.E. Kim, I.S. Ko, H.-G. Lee, S.B. Lee, B.G. Oh, K.-H. Park
PAL, Pohang, Kyungbuk, Republic of Korea

We have designed and tested magnets for PAL-XFEL of 10GeV in Pohang, Korea. These magnets consist of 6 families of 52 dipole magnets, 11 families of 236 quadrupole magnets, and 4 families of 10⁸ corrector magnets. Two hall probe benches are used to measure the magnetic field. This paper reviews the main parameters of these magnets and the results of magnetic field measurements.

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TUPMB038

Degradation of the Insulation of the LHC Main Dipole Cable when Exposed to High Temperatures

dipole, superconducting-magnet, operation, high-voltage

1186

V. Raginel, B. Auchmann, D. Kleiven, R. Schmidt, A.P. Verweij, D. Wollmann
CERN, Geneva, Switzerland

Funding: Research supported by the High Luminosity LHC project
The energy stored in the LHC beams is substantial and requires a complex machine protection system to protect the equipment. Despite efficient beam absorbers, several failure modes lead to some limited beam impact on superconducting magnets. Thus it is required to understand the damage mechanisms and limits of superconducting magnets due to instantaneous beam impact. This becomes even more important due to the future upgrade of CERNs injector chain for the LHC that will lead to an increase of the beam brightness. A roadmap to perform damage tests on magnet parts has been presented previously*. The polyimide insulation of the superconducting cable is identified as one of the critical elements of the magnet. In this contribution, the experimental setup to measure the insulation degradation of LHC main dipole cables due to exposure to high temperature is described. Compressed stacks of insulated Nb-Ti cables have been exposed to a heat treatment within an Argon atmosphere. After each heat treatment, high-voltage measurements verified the dielectric strength of the insulation. The results of this experiment provide an upper damage limit of superconducting magnets due to beam impact.
* Experimental Setups to Determine the Damage Limit of Superconducting Magnets for Instantaneous Beam Losses, V. Raginel et al, IPAC'15

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TUPMR030

Progress on RFQ Fabrication for RISP Accelerator

rfq, vacuum, alignment, cavity

1308

B.-S. Park, B.H. Choi, I.S. Hong
IBS, Daejeon, Republic of Korea

The 81.25MHz Radio Frequency Quadrupole(RFQ), which was designed to accelerate various ion beams from the energy of 10 keV/u to 500 keV/u, is under development for the Rare Isotope Science Project(RISP). The 5 meter long RFQ consists of 9 sections and the total weight is roughly 16 tons. Each sections of RFQ aligned and installed by using a laser tracker on a supporter system. In this paper, the fabrication status of the RISP RFQ and the scheme of installation were described in detail.
This work was supported by the RISP of IBS funded by the Ministry of Science, ICT and Future Planning(MSIP) and the National Research Foundation(NRF) of Korea(2013M7A1A1075764).

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TUPMR052

Commissioning Preparation of the AWAKE Proton Beam Line

proton, plasma, experiment, extraction

1374

J.S. Schmidt, B. Biskup, C. Bracco, B. Goddard, R. Gorbonosov, M. Gourber-Pace, E. Gschwendtner, L.K. Jensen, O.R. Jones, V. Kain, S. Mazzoni, M. Meddahi
CERN, Geneva, Switzerland

The AWAKE experiment at CERN will use a proton bunch with an momentum of 400 GeV/c from the SPS to drive large amplitude wakefields in a plasma. This will require a ~830 m long transfer line from the SPS to the experiment. The prepa- rations for the beam commissioning of the AWAKE proton transfer line are presented in this paper. They include the detailed planning of the commissioning steps, controls and beam instrumentation specifications as well as operational tools, which are developed for the steering and monitoring of the beam line. The installation of the transfer line has been finished and first beam is planned in summer 2016.

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TUPMW003

Integration, Configuration and Coordination: from Project to Reality, at CERN

ECR, database, survey, status

1407

M. Barberan Marin, S. Bartolome-Jimenez, M. Bernardini, T.W. Birtwistle, S. Chemli, J.-P. Corso, J. Coupard, K. Foraz, S. Grillot, Y. Muttoni, A.-L. Perrot
CERN, Geneva, Switzerland

The rigorous process in place at CERN to approve and follow-up the implementation of any modification of the LHC machine and its Injectors is presented in this paper. Our methodology implies the support of three teams, in charge of the configuration management, the scheduling and safety coordination, and the 3D integration studies. At each stage of the project the support of the three teams evolves, to provide the adequate support in the preparation phase and during the technical stops and long shutdowns. The formal roles and the processes used to govern the interaction of the Integration, Configuration and Coordination teams, and their relation to the project teams during the preparation and implementation phases, for activities to be performed in LHC and its injector chain are described and discussed.

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TUPMY015

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

electron, gun, acceleration, 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.

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TUPMY016

Design of a Collection and Selection System for High Energy Laser-driven Ion Beams

ion, dipole, quadrupole, proton

1581

F. Schillaci, L. Allegra, A. Amato, L. Andò, G.A.P. Cirrone, M. Costa, G. Cuttone, G. De Luca, G. Gallo, J. Pipek, F. Romano
INFN/LNS, Catania, Italy
G. Korn, D. Margarone, V. Scuderi
ELI-BEAMS, Prague, Czech Republic
M. Maggiore
INFN/LNL, Legnaro (PD), Italy

Funding: ELI-Beamlines Contract n.S14-187, LaserGen(CZ.1.07/2.3.00/30.0057), Ministry of Education of Czech Rep.(reg. No.CZ.1.05/1.1.00/02.0061), the FZU, AVCR, v.v.i and the project financed by ESF and Czech Rep.
Laser-target acceleration represents a very promising alternative to conventional accelerators for several potential applications, from the nuclear physics to the medical ones. However, some extreme features, not suitable for multidisciplinary applications, as the wide energy and angular spreads are typical of optically accelerated ion beams. Therefore, beyond the improvements at the laser-target interaction level, a lot of efforts have been recently devoted to the development of specific beam-transport devices in order to obtain controlled and reproducible output beams. In this framework, a three years contract has been signed between INFN-LNS (IT) and Eli-Beamlines-IoP (CZ) to provide the design and the realization of a complete transport beam-line, named ELIMED, dedicated to the transport, diagnostics and dosimetry of laser-driven ion beams. The transport devices will be composed by a set of super-strong permanent magnet quadrupoles able to collect and focus laser driven ions up to 70MeV/u, and a magnetic chicane made of conventional electromagnetic dipole to select particles within a narrow energy range. Here, the design and development of these magnetic systems is described.

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TUPMY017

Laser Driven Dielectric Accelerator in the Non-relativistic Energy Region

acceleration, electron, 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.

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TUPMY018

Recent Progress of Proton Acceleration at Peking University

electron, 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.

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TUPMY019

CLAPA Proton Beam Line in Peking University

proton, target, plasma, ion

1592

J.G. Zhu, J.E. Chen, C. Lin, H.Y. Lu, W.J. Ma, L. Tao, X.Q. Yan, K. Zhu
PKU, Beijing, People's Republic of China

Comparing with the conventional accelerator, the laser plasma accelerator can accelerate ions more effectively and greatly reduce the scale and cost. A laser accelerator− Compact Laser Plasma Accelerator (CLAPA) is being built at Institute of Heavy Ion physics of Peking University. According to the beam parameters from proof of principle experiments and theoretical simulations, we design the beam line for ions transport which is being built now and in the near future we will carry out experimental study with it. The beam line is mainly constituted by quadrupole and analyzing magnets . The quadrupole triplet lens collects protons generated from the target, while the analyzing magnet system will choose the protons with proper energy. The transport is simulated by program TRACK. The beam line is designed to deliver proton beam with the energy of 1~ 40MeV, energy spread of ±1% and 106-8 protons per pulse to satisfy the requirement of different experiments. The transmission efficiency is about 94% when the energy spread is ±1%.

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TUPMY023

Advanced Gabor Lens Lattice for Laser Driven Hadron Therapy and Other Applications

lattice, collimation, ion, cavity

1595

J.K. Pozimski, M. Aslaninejad, P.A. Posocco
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

Funding: Funding was provided by the Imperial Confidence in Concept scheme.
The application of laser accelerated ion beams in hadron therapy requires a beam optics with unique features. Due to the spectral and spatial distribution of laser accelerated protons a compact ion optical system with therapy applications, based on Gabor space charge lenses for collecting, focusing and energy filtering the laser produced proton beam, has significant advantages compared with other setups. While a passive momentum selection could improve already the usability of laser driven hadron, we show that an advanced lattice utilizing additional RF cavities not only will deliver a momentum spread smaller than conventional accelerators, but also will increases the dose delivered. Furthermore, a possible near term application in the field of radio nuclide production is presented.

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TUPMY026

Electron Beam Generation and Injection From a Pyroelectric Crystal Array

acceleration, electron, 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).

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TUPMY028

Ultra-high Gradient Acceleration in Nano-crystal Channels

electron, plasma, 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)

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TUPMY030

Measurements of Transmitted Electron Beam Extinction through Si Crystal Membranes

electron, emittance, scattering, 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.

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TUPMY036

Drive Generation and Propagation Studies for the Two Beam Acceleration Experiment at the Argonne Wakefield Accelerator

kicker, simulation, power-supply, wakefield

1629

N.R. Neveu, M.E. Conde, D.S. Doran, W. Gai, G. Ha, C.-J. Jing, W. Liu, J.G. Power, D. Wang, C. Whiteford, E.E. Wisniewski
ANL, Argonne, Illinois, USA
S.P. Antipov, C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
G. Ha
POSTECH, Pohang, Kyungbuk, Republic of Korea
N.R. Neveu
IIT, Chicago, Illinois, USA
D. Wang
TUB, Beijing, People's Republic of China

Funding: Work supported by by the U.S. Department of Energy under contract No. DE-AC02-06CH11357.
Simplified staging in a two beam accelerator (TBA) has been accomplished at the Argonne Wakefield Accelerator (AWA) facility. This layout consists of a drive beamline and witness beamline operating synchronously. The drive photoinjector linac produces a 70 MeV drive bunch train of eight electron bunches (charge per bunch between 5-40 nC) that pass through decelerating structures in each TBA stage. The witness linac produces an 8 MeV witness bunch that passes through the accelerating structures in each TBA stage. Recent effort has been focused on improving the uniformity of the UV laser pulses that generate the bunch trains. Current work at the AWA is focused on the transition from simplified staging to full staging. A kicker will be designed and installed to direct bunch trains to one TBA stage only. Preliminary calculations and simulation results are presented.

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TUPMY041

Delivery Status of the ELI-NP Gamma Beam System

gun, solenoid, linac, vacuum

1635

S. Tomassini, D. Alesini, A. Battisti, R. Boni, F. Cioeta, A. Delle Piane, E. Di Pasquale, G. Di Pirro, A. Falone, A. Gallo, S.I. Incremona, V.L. Lollo, A. Mostacci, S. Pioli, R. Ricci, U. Rotundo, A. Stella, C. Vaccarezza, A. Vannozzi, A. Variola
INFN/LNF, Frascati (Roma), Italy
A. Bacci, D.T. Palmer, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano, Italy
N. Bliss
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
F. Cardelli
INFN-Roma1, Rome, Italy
K. Cassou, Z.F. Zomer
LAL, Orsay, France
G. D'Auria
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
A. Giribono, V. Pettinacci
INFN-Roma, Roma, Italy
C. Hill
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
L. Palumbo
Rome University La Sapienza, Roma, Italy
L. Piersanti
University of Rome La Sapienza, Rome, Italy

The ELI-NP GBS is a high intensity and monochromatic gamma source under construction in Magurele (Romania). The design and construction of the Gamma Beam System complex as well as the integration of the technical plants and the commissioning of the overall facility, was awarded to the Eurogammas Consortium in March 2014. The delivery of the facility has been planned in for 4 stages and the first one was fulfilled in October 31st 2015. The engineering aspects related to the delivery stage 1 are presented.

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TUPOR019

RF Injector Beam Dynamics Optimization and Injected Beam Energy Constraints for LCLS-II

cavity, emittance, electron, 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.

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TUPOW004

Status of the STAR Project

electron, 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.

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TUPOW008

Generation of Short Bunch Electron Beam from Compact Accelerator for Terahertz Radiation

electron, 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.

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TUPOW025

First Beam Test of the High Brightness Photo-injector at NSRRC

gun, linac, electron, 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.

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TUPOW027

Model Independent Analysis of Beam Jitter on VELA

cathode, timing, distributed, gun

1806

J.K. Jones, K.D. Dumbell, A.J. Moss, E.W. Snedden
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The Versatile Electron Linear Accelerator (VELA) is a facility designed to provide high quality electron beams for accelerator systems development, as well as industrial and scientific applications. A key performance indicator for many applications is the inherent beam jitter on the machine (temporal, momentum and positional). Analysis of this beam jitter indicates that there are several independent mechanisms driving the beam motion. We use model independent analysis to correlate various dominant modes of beam jitter and compare them to simulations. We also compare the dominant modes before and after intervention work on the DLLRF timing system, and determine the relevant changes in beam motion.

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TUPOW028

Comparison of Model vs. Reality for VELA

gun, cathode, simulation, solenoid

1810

M.S. Toplis, J.W. McKenzie, B.D. Muratori, D.J. Scott, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The Versatile Electron Linear Accelerator (VELA) is a facility designed to provide a high quality electron beam for accelerator systems development, as well as industrial and scientific applications. Currently, the RF gun can deliver short bunches, of the order of 100 fs to a few ps, with a charge of up to 250 pC, at the longer bunch lengths, and up to 4.5 MeV/c beam momentum. A model for the injector has been developed in ASTRA, together with a suite of scripts to create scans of the available parameters around an empirically found arbitrarily optimal working point. The space of parameters consists of everything that can be changed in the control room, and ranges from bunch charge to laser spot size on the cathode, together with all magnet settings where and if necessary. The various scans facilitate the task of identifying where exactly the accelerator is in terms of parameters and trends. Initial comparisons of screen images are made between the model and reality. Ultimately, the goal of the model is to robustly and repeatably establish a desired operating setup on a daily basis from an unknown switch on condition.

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TUPOW036

Recent Developments and Operational Status of the Compact ERL at KEK

operation, linac, emittance, gun

1835

T. Obina, M. Adachi, S. Adachi, T. Akagi, M. Akemoto, D.A. Arakawa, S. Araki, S. Asaoka, M. Egi, K. Enami, K. Endo, S. Fukuda, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, K. Hozumi, A. Ishii, X.J. Jin, E. Kako, Y. Kamiya, H. Katagiri, R. Kato, H. Kawata, Y. Kobayashi, Y. Kojima, Y. Kondo, T. Konomi, A. Kosuge, T. Kume, T. Matsumoto, H. Matsumura, H. Matsushita, S. Michizono, T. Miura, T. Miyajima, H. Miyauchi, S. Nagahashi, H. Nakai, H. Nakajima, N. Nakamura, K. Nakanishi, K. Nakao, K.N. Nigorikawa, T. Nogami, S. Noguchi, S. Nozawa, T. Ozaki, F. Qiu, H. Sagehashi, H. Sakai, S. Sakanaka, S. Sasaki, K. Satoh, Y. Seimiya, T. Shidara, M. Shimada, K. Shinoe, T. Shioya, T. Shishido, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, T. Takenaka, O. Tanaka, Y. Tanimoto, N. Terunuma, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, J. Urakawa, K. Watanabe, M. Yamamoto, N. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida
KEK, Ibaraki, Japan
R. Hajima, M. Mori, R. Nagai, N. Nishimori, M. Sawamura, T. Shizuma
QST, Tokai, Japan
M. Kuriki
Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan

The Compact Energy Recovery Linac (cERL) at KEK is a test accelerator in order to develop key components to realize remarkable ERL performance as a future light source. After the beam commissioning in December 2013, the legal current limit has been increased step-by-step like 1 uA, 10 uA, and 100 uA. Survey for the source of beam losses has been conducted in each step, and the study on beam dynamics and tuning has also been carried out. As a next step, 1 mA operation is scheduled in February 2016. In parallel to the increase in beam current, a laser Compton scattering (LCS) system which can provide high-flux X-ray to a beamline has been successfully commissioned. We report recent progress in various kinds of beam tuning: improvement of electron gun performance, high bunch charge operation, mitigation of beam losses, LCS optics tuning and bunch compression for THz radiation.

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TUPOW041

Optimization Studies for the Beam Dynamic in the RF Linac of the ELI-NP Gamma Beam System

electron, 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.

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TUPOW042

Expected Gamma Spectra at ELI-NP-GBS

photon, polarization, electron, 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.

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TUPOW046

Development and Upgrade Plan of an X-ray Source Based on Laser Compton Scattering in Laser Undulator Compact X-ray Source(LUCX)

electron, 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.

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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

electron, 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.

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TUPOW052

LLNL Laser-Compton X-ray Characterization

electron, 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.

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TUPOW053

Measurement of Terahertz Generation in a Metallic, Corrugated Beam Pipe

radiation, electron, experiment, dipole

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.

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TUPOW054

Characterization of a Sub-THz Radiation Source Based on a 3 MeV Electron Beam and Future Plans

electron, radiation, experiment, quadrupole

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.

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TUPOY003

Novel Approach to Utilize Proton Beams from High Power Laser Accelerators for Therapy

proton, acceleration, target, radiation

1905

U. Masood, M. Baumann, W. Enghardt, L. Karsch, J. Pawelke, S. Schürer
OncoRay, Dresden, Germany
M. Baumann
German Cancer Research Center (DKFZ), Heidelberg, Germany
M. Baumann
German Cancer Consortium (DKTK), Dresden, Germany
T.E. Cowan, U. Schramm
Technische Universität Dresden, Dresden, Germany
T.E. Cowan, W. Enghardt, T. Herrmannsdoerfer, J. Pawelke, U. Schramm
HZDR, Dresden, Germany
K.M. Hofmann, J.J. Wilkens
Technische Universität München, Klinikum rechts der Isar & Physics Department, Munich, Germany
F. Kroll
Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany

Funding: Supported by German BMBF, nos. 03Z1N511 and 03Z1O511 & DFG cluster of excellence MAP.
Protons provide superior radiotherapy benefits to patients, but immense size and cost of the system limits it to only few centers worldwide. Proton acceleration on μm scale via high intensity laser is promising to reduce size and costs of proton therapy, but associated beamlines are still big and massive. Also, in contrast to conventionally accelerated quasi-continuous mono-energetic pencil beams, laser-driven beams have distinct beam properties, i.e. ultra-intense pico-sec bunches with large energy spread and large divergences, and with low repetition rate. With new lasers with petawatt power, protons with therapy related energies could be achieved, however, the beam properties make it challenging to adapt them directly for medical applications. We will present our compact beamline solution including energy selection and divergence control, and a new beam scanning and dose delivery system with specialized 3D treatment planning system for laser-driven proton beams. The beamline is based on high field iron-less pulsed magnets and about three times smaller than the conventional systems*, and can provide high quality clinical treatment plans**.
* U. Masood et al, Applied Phys B, 117(1):41-52, 2014
** K.M. Hofmann et al, Medical Physics, 42(9):5120-5129, 2015

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TUPOY027

Beam Dynamics Studies into Grating-based Dielectric Laser-driven Accelerators

electron, 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.

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TUPOY040

Advancements in Single-shot Electron Diffraction on VELA at Daresbury Laboratory

electron, 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.

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TUPOY046

Study on NRF-CT Imaging by Laser Compton Backscattering Gamma-rays in UVSOR

target, detector, photon, resonance

2007

H. Ohgaki, I. Daito, T. Kii, H. Zen
Kyoto University, Kyoto, Japan
T. Hayakawa, T. Shizuma
JAEA, Ibaraki-ken, Japan
M. Katoh, J. Yamazaki
UVSOR, Okazaki, Japan
Y. Taira, H. Toyokawa
AIST, Tsukuba, Japan

Funding: This work was supported by JSPS KAKENHI Grant Number 26289363, 24340060 and the Joint Studies Program (2014) of the Institute for Molecular Science.
Monochromatic gamma-ray beam in MeV energy region is suitable for non-destructive inspection of high density and massive objects because of its high penetrability. A specific nuclide can be detected by the process of Nuclear Resonance Fluorescence (NRF). A non-destructive inspection of Special Nuclear Materials hidden in a container cargo using NRF is proposed by Bertozzi*. Non-destructive detection of Pu inside of a spent nuclear fuel rod is also proposed for management of radioactive wastes, nuclear material accounting and safeguards**. We have developed 2D NRF imaging by using quasi-monochromatic gamma-ray beam in MeV energy region generated by Laser Compton Backscattering (LCS) method*** and proposed to develop an NRF-CT image in the ELI-NP where a high intensity LCS beam can be available in near future. To demonstrate and finalize the measurement system of the NRF-CT imaging by using LCS gamma-ray beam, we have started a study on NRF-CT imaging at the new LCS beamline in UVSOR. The LCS beamline can generate 5.4 MeV LCS gamma-rays with a flux of 1×10⁷ photons/s. We have measured the 5.291 MeV NRF gamma-rays from a lead target in this beamline and tried to take a NRF-CT image.
* W. Bertozzi et al., Nucl. Inst. Meth. B241, 820-825 (2005).
** B. Ludewigt et al., Proc. of 2010 ANS meeting (2010).
*** H. Toyokawa et al., JJAP, 50, 100209 (2011).

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WEXB01

Status, Plans and Potential Applications of the ELIMED Beam Line at ELI-Beamlines

ion, proton, acceleration, target

2077

G.A.P. Cirrone, L. Allegra, A. Amato, A. Amico, G. Candiano, A.C. Caruso, L. Cosentino, M. Costa, G. Cuttone, G. De Luca, G. Gallo, S. Gammino, G. Larosa, R. Leanza, R. Manna, V. Marchese, G. Milluzzo, G. Petringa, J. Pipek, P.S. Pulvirenti, F. Romano, S. Salamone, F. Schillaci, V. Scuderi
INFN/LNS, Catania, Italy
G. Korn, D. Margarone, V. Scuderi
ELI-BEAMS, Prague, Czech Republic

Charged particle acceleration using ultra-intense and ultra-short laser pulses has gathered a strong interest in the scientific community and it is now one of the most attractive topics in the relativistic laser-plasma interaction research. Indeed, it could represent the future of particle acceleration and open new scenarios in multidisciplinary fields, in particular, medical applications. One of the biggest challenges consists of using, in a future perspective, high intensity laser-target interaction to generate high-energy ions for therapeutic purposes, eventually replacing the old paradigm of acceleration, characterized by huge and complex machines. In this framework, INFN-LNS (Italian Institute of Nuclear Physics, Catania (I)) in collaboration with ELI-Beamline Institute (Dolny Brezany, CZ) will realise, within 2017 the ELIMED (ELI-Beamlines MEDical and multidisciplinary applications) beamline. ELIMED will be the first Users' addressed transport beamline dedicated to the medical and multidisciplinary studies with laser-accelerated ion beams.

Slides WEXB01 [29.683 MB]

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WEOAB01

Advanced Acceleration Mechanisms for Laser Driven Ions by PW-lasers

ion, acceleration, target, electron

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]

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WEOAB02

Record Performance of SRF Gun with CsK2Sb Photocathode

cathode, gun, electron, 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]

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WEOAB03

Photoemission Properties of LaB6 and CeB6 Under Various Temperature and Incident Photon Energy Conditions

cathode, photon, electron, 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]

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WEPMB018

Multipactor Simulations in 650 MHz Superconducting Spoke Cavity for an Electron Accelerator

cavity, electron, simulation, multipactoring

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.

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WEPMB025

Fabrication of Superconducting Spoke Cavity for Laser Compton Scattered Photon Sources

cavity, photon, simulation, linac

2177

M. Sawamura, R. Hajima
QST, Tokai, Japan
H. Hokonohara, Y. Iwashita, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
T. Kubo, T. Saeki
KEK, Ibaraki, 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.
We have launched a 5-year research program to develop superconducting spoke cavity for laser Compton scattered (LCS) photon sources. For realizing a wide use of LCS X-ray and γ-ray sources in academic and industrial applications, we adopt the super-conducting spoke cavity to electron beam drivers. The spoke cavity has advantages such as relative compactness in comparison with an elliptical cavity of the same frequency, robustness with respect to manufacturing inaccuracy due to its strong cell-to-cell coupling, the better packing in a linac to install couplers on outer conductor. On the other hand the spoke cavity has disadvantage of more complicated structure than an elliptical cavity. Though our proposal design for the photon source consists of the 325 MHz spoke cavities in 4K operation, we have begun to fabricate the half scale model of 650 MHz spoke cavity in order to accumulate our cavity production experience by effective utilization of our limited resources. In this paper, we present our fabrication status.

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WEPMB049

Transverse Defocusing Study in LPWA Channel for Linear and Bubble Modes

plasma, electron, 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

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WEPMR014

RF Design of a High Average Beam-Power SRF Electron Source

electron, cavity, SRF, 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.

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WEPMR015

Surface Topography Techniques at Cornell University: Optical Inspection and Surface Replica

cavity, SRF, controls, GUI

2292

G.M. Ge, F. Furuta, D. Gonnella, D.L. Hall, G.H. Hoffstaetter, M. Liepe, T.I. O'Connell, J. Sears
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Surface imperfections significantly limit the performance of superconducting radio frequency (SRF) cavities. The development of surface topography techniques aims to locate the surface flaws in an SRF cavity and profile their geometry details. This effort plays an important role of quality control in cavity productions as well as provides contour information of the defects for understanding quench mechanisms. The surface topography techniques at Cornell University include an optical inspection system and surface replica technique. In this paper, we present the details of the techniques and show features found in the SRF cavities at Cornell.

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WEPMY003

Simulations of the Acceleration of Externally Injected Electrons in a Plasma Excited in the Linear Regime

electron, plasma, 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.

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WEPMY004

Development of an Injector and a Magnetic Transfer Line in the Framework of Cilex

electron, 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.

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WEPMY005

Upgrades of the Experimental Setup for Electron Beam Self-modulation Studies at PITZ

plasma, electron, 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.

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WEPMY006

A High Transformer Ratio Scheme for PITZ PWFA Experiments

plasma, wakefield, acceleration, simulation

2551

G. Loisch, M. Groß, H. Huck, A. Oppelt, Y. Renier, F. Stephan
DESY Zeuthen, Zeuthen, Germany
A. Aschikhin, A. Martinez de la Ossa, J. Osterhoff
DESY, Hamburg, Germany
M. Hochberg, M. Sack
KIT, Karlsruhe, Germany

In the field of plasma wakefield acceleration (PWFA) significant progress has been made throughout the recent years. However, an important issue in building plasma based accelerators that provide particle bunches suitable for user applications will be a high transformer ratio, i.e. the ratio between maximum accelerating field in the witness and maximum decelerating fields in the driver bunch. The transformer ratio for symmetrical bunches in an overdense plasma is naturally limited to 2*. Theory and simulations show that this can be exceeded using asymmetrical bunches. Experimentally this was proven in RF-structures**, but not in PWFA. To study transformer ratios above this limit in the linear regime of a plasma wake, an experimental scheme tailored to the unique capabilities of the Photoinjector Test Facility Zeuthen PITZ, a 20-MeV electron accelerator at DESY, is being investigated. This includes analytical plasma wakefield calculations, numerical simulations of beam transport and plasma wakefields, as well as preparatory studies on the photocathode laser system and the plasma sources.
* K. L. F. Bane, P. B. Wilson and T. Weiland, AIP Conference Proceedings 127, p. 875, 1984
** C. Jing et al., Physical Review Letters 98, 144801, 2007

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WEPMY007

Plasma Density Profile Characterization for Resonant Plasma Wakefield Acceleration Experiment at SPARC_LAB

plasma, electron, 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.

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WEPMY011

Compact Laser Plasma Accelerator at Peking University

plasma, acceleration, electron, 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)

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WEPMY013

A Spatially Separated Two Frequency RF Gun Design for Beam Brightness Improvement

gun, emittance, cavity, brightness

2572

Z. Zhang, C.-X. Tang, Z. Zhang
TUB, Beijing, People's Republic of China
H.J. Qian
LBNL, Berkeley, California, USA

Recent theoretical and experimental studies shows that transverse beam brightness of photoinjector can be improved by cigar beam photoemission, and beam peak current are then increased with a RF buncher following the gun. We apply this concept to a S-band photoinjector by adding a harmonic RF buncher closely to a S-band RF gun, forming a compact spatially separated two frequency RF gun, targeting a 200 pC beam with emittance < 0.2 mm·mrad and 30 A peak current. Both S/X-band and S/C-band combinations are considered, and an optimized solution with 30 A peak current and 0.1 mm·mrad slice emittance are presented.

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WEPMY014

Feasibility Study of a Laser-Driven High Energy Electron Acceleration in a Long Up-Ramp Density

electron, plasma, 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).

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WEPMY015

Numerical Studies on Tunable Coherent Radiations with a Laser-Plasma Accelerator

electron, plasma, 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).

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WEPMY019

AWAKE, the Advanced Proton Driven Plasma Wakefield Acceleration Experiment

plasma, wakefield, electron, 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.

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WEPMY020

Integration of a Terawatt Laser at the CERN SPS Beam for the AWAKE Experiment on Proton-Driven Plasma Wake Acceleration

plasma, proton, electron, 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.

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WEPMY036

Laser Ablation Ion Source for Highly Charge-State Ion Beams

ion, extraction, plasma, target

2632

N. Munemoto, K. Horioka
TIT, Yokohama, Japan
K. Okamura, S. Takano, K. Takayama
KEK, Ibaraki, Japan
K. Okamura, K. Takayama
Sokendai, Ibaraki, Japan

The KEK Laser ablation ion source (KEK-LAIS) is un-der development in order to generate highly ionized metal and fully ionized carbon ions for future applica-tions*. Laser ablation experiments have been carried out by using Nd-YAG laser (0.75 J/pulse, 20 ns) at the KEK test bench. Basic parameters such as a charge-state spec-trum and momentum spectrum of the plasma and extract-ed ion beam current have been obtained. Extraction of C ions from the LAIS is described.
* N.Munemoto et al., Rev. Sci. Inst. 85, 02B922 (2014)

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WEPMY039

Time Response Measurements for Transmission-Type GaAs/GaAsP Superlattice Photocathodes

electron, 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.

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WEPMY040

Fabrication of Two Dimensional Nano-Scale Photocathode Arrays in Transparent Conductor for High Coherence Beam Generation

electron, 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.

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WEPOR017

A Micrometric Positioning Sensor for Laser-Based Alignment

experiment, alignment, target, vacuum

2700

G. Stern, H. Mainaud Durand, D. Piedigrossi, M. Sosin
CERN, Geneva, Switzerland
A. Geiger, S. Guillaume
ETH, Zurich, Switzerland

The Compact Linear Collider requires 10 μm accuracy over 200m for the alignment of its components. Since current techniques based on stretched wire or water level are difficult to implement, other options are under study. We propose a laser alignment system using positioning sensors made of camera/shutter assemblies. The goal is to implement such a positioning sensor. The corresponding studies comprise design and calibration as well as investigations of measurement accuracy and precision. On the one hand, we describe mathematically the laser beam propagation, its interaction with the shutter and image processing. On the other hand, we present experiments done with the prototype of a positioning sensor. As a result, we give practical suggestions to build the positioning sensors and we describe a calibration protocol to be applied to all sensors before measuring. In addition, we deliver estimates for measurement accuracy and precision. Our work provides the first steps towards a full alignment system.

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WEPOR032

Power Recycling of Burst-mode Laser Pulses for Laser Particle Interactions

cavity, resonance, experiment, ion

2739

Y. Liu, A. Rakhman
ORNL, Oak Ridge, Tennessee, USA
A. Rakhman
UTK, Knoxville, Tennessee, USA

Funding: This work has been partially supported by U.S. DOE grant DE-FG02-13ER41967. ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE.
A number of laser-particle interaction experiments such as the laser assisted hydrogen ion beam stripping or X-/γ-ray generations via inverse-Compton scattering involve light sources operating in a burst mode to match the temporal structure of the particle beam. As the small cross-section in the laser-particle interaction process results in negligible laser power loss, it is desirable to make the interaction inside an optical cavity to recycle the laser power. In many cases, conventional cavity locking techniques will not work since the burst normally has very small duty factor and low repetition rate and it is impossible to generate an effective control signal. In this talk, we report on the development of a doubly-resonant optical cavity scheme and its locking technique that enables a simultaneous resonance of two laser beams with different spectra and/or temporal structures. We demonstrate that such a cavity can be used to recycle burst-mode ultra-violet laser pulses with arbitrary burst lengths and repetition rates. System implementation, technical challenges, experimental results and applications will be described.
* V. Danilov et al., Phys. Rev. ST Accel. Beams 10, 053501 (2007).
** K. Sakaue et al., Rev. Sci. Instrum. 80, 123304 (2009).
*** A. Rakhman, M. Notcutt, and Y. Liu, Opt. Lett. 40, 5562 (2015).

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WEPOR034

Design and Evaluation of a Broad Band microTCA.4 Based Downconverter

LLRF, controls, radio-frequency, electron

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.

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WEPOR060

MTCA.4-based Beam Line Stabilization Application

FPGA, detector, controls, optics

2808

K.P. Przygoda
TUL-DMCS, Łódź, Poland
C. Gerth, H. Schlarb, B. Steffen
DESY, Hamburg, Germany

We want to summarize the beam line stabilization application with MTCA.4 electronics. Presented solution is based on the compact 2U MTCA.4 crate integrating sensor and actuator cards. The optical beam position sensor is based on quadrupole SI PIN photodiode connected to low cost AMC based FMC carrier equipped with ADC card. The optical beam position correction is done using picomotorized stages equipped with active piezo elements and high voltage RTM piezo driver. The data processing and digital feedback units are implemented using Spartan 6 FPGA. The control algorithm has been optimized for low latency and high precision computations. The control electronics performance has been tested using single beam line test stand consisted of commercial laser diode drivers, supported optics and motorized stages. The first results are demonstrated and future possible applications are briefly discussed.

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WEPOW013

Coherent Harmonic Generation in the Presence of Synchronized RF Phase Modulation at DELTA

electron, resonance, synchrotron, 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.

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WEPOW014

Spectral Studies of Ultrashort and Coherent Radiation Pulses at the DELTA Storage Ring

radiation, electron, 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.

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WEPOW019

SPring-8 Upgrade Project

undulator, emittance, operation, radiation

2867

H. Tanaka, T. Ishikawa
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
S. Goto, S. Takano, T. Watanabe, M. Yabashi
JASRI/SPring-8, Hyogo, Japan

Plans are underway for the upgrade of the SPring-8 facility, targeting completion in the early 2020's. Sustainability is a key guiding principle for the fourth-generation X-ray source - a beam emittance of around 100 pm.rad is pursued simultaneously with substantial energy-saving. The three key features of the design are (i) to replace the main dipole electric magnets with permanent magnets, (ii) to reduce the electron beam energy from 8 to 6 GeV, and (iii) to use the SACLA linac as an injector. Lowering the beam energy leads to reduction of (a) beam emittance, (b) magnetic fields, (c) the lengths of ID straight sections to maintain larger spaces for the magnets, and (d) the RF power consumption. Timeshare use of the SACLA linac enables beam injection to the upgraded ring with a low-emittance and short-pulsed beam as well as a reduction of injector power consumption by stopping the present injector consisting of a 1-GeV linac and a booster synchrotron. The outline of the upgrade plan will be reported with the current status of R&D started in 2015.

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WEPOW055

Bayesian Optimization of FEL Performance at LCLS

FEL, controls, interface, electron

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.

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WEPOY021

Nonlinear Phase Distortion in a Ti:Sapphire Optical Amplifier for Optical Stochastic Cooling

undulator, radiation, kicker, pick-up

3024

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.
Optical Stochastic Cooling (OSC) has been considered for future high-luminosity colliders as it offers much faster cooling time in comparison to the micro-wave stochastic cooling. The OSC technique relies on collecting and amplifying a broadband optical signal from a pickup undulator and feeding the amplified signal back to the beam. It creates a corrective kick in a kicker undulator. Owing to its superb gain qualities and broadband amplification features, Titanium:Sapphire medium has been considered as a gain medium for the optical amplifier (OA) needed in the OSC*. A limiting factor for any OA used in OSC is the possibility of nonlinear phase distortions. In this paper we experimentally measure phase distortions by inserting a single-pass OA into one leg of a Mach-Zehnder interferometer. The measurement results are used to estimate the reduction of the corrective kick a particle would receive due to these phase distortions in the kicker undulator.
* A. Zholents, and M. Zolotorev. Proc. PAC'97, 1805 (1998).

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WEPOY024

Beam Dynamics Simulations of the Thomx Linac

emittance, gun, solenoid, electron

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.

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WEPOY028

Laser Heater System Test at PAL-XFEL ITF

electron, 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.

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WEPOY038

Design of a Collection and Selection System for High Energy Laser-Driven Ion Beams

quadrupole, permanent-magnet, proton, ion

3070

F. Schillaci, G.A.P. Cirrone, G. Cuttone, D. Rifuggiato
INFN/LNS, Catania, Italy
M. Maggiore
INFN/LNL, Legnaro (PD), Italy

Laser-based accelerators are gaining interest in recent years as an alternative to conventional machines. Nowadays, energy and angular spread of the laser-driven beams are the main issues in application and different solutions for dedicated beam-transport lines have been proposed. In this context a system of permanent magnet quadrupoles has been realized, by INFN researchers in collaboration with SIGMAPHI company, to be used as a collection system for laser-driven protons up to 20 MeV. The definition of well specified characteristics, in terms of performances and field quality, of the magnetic lenses is crucial for the system realization and an accurate study of the beam dynamics. Hence, a method for studying the errors on the PMQ harmonic contents has been developed. It consists of different series of simulations in which magnetic and mechanical errors are introduced in the array and the harmonic content is analyzed to fix the tolerances necessary to have a good beam quality downstream the system. The method developed for the analysis of the PMQs errors and its validation is here described. The technique is general and can be easily extended to any magnetic lens.

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THOBA03

Start-to-end Calculations and Trajectory Correction for BERLinPro

linac, simulation, space-charge, timing

3167

B.C. Kuske, C.J. Metzger-Kraus
HZB, Berlin, Germany

Funding: Work funded by the Bundesministerium für Bildung und Forschung, Land Berlin and grants of the Helmholtz Association
BERLinPro is an ERL project under construction at the Helmholtz-Zentrum Berlin, with the goal to illuminate the challenges and promises of a high brightness 100 mA superconducting RF gun in combination with a 50 MeV return loop and energy recovery. Latest changes to the optics code OPAL allow for the first time to perform start-to-end tracking studies including space charge in a single run, without switching between codes. This opens the way to apply correction schemes to displaced trajectories in the complete machine and to study the effect of jitter sources, including the space charge dominated injector, on the machine performance parameters. Trajectory correction is discussed. Jitter is studied with respect to its potential impact on the recovery process and parameter changes before the dump.

Slides THOBA03 [5.903 MB]

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THOAB03

Ultrafast Electron Microscopy using 100 Femtosecond Relativistic-Energy Electron Beam

electron, emittance, gun, brightness

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.

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THPPA01

Demonstration of the Hollow Channel Plasma Wakefield Accelerator

plasma, positron, acceleration, wakefield

3202

S.J. Gessner, J.M. Allen, C.I. Clarke, J.-P. Delahaye, J.T. Frederico, S.Z. Green, C. Hast, M.J. Hogan, N. Lipkowitz, M.D. Litos, B.D. O'Shea, D.R. Walz, V. Yakimenko, G. Yocky
SLAC, Menlo Park, California, USA
E. Adli, C.A. Lindstrøm
University of Oslo, Oslo, Norway
W. An, C.E. Clayton, C. Joshi, K.A. Marsh, W.B. Mori, N. Vafaei-Najafabadi
UCLA, Los Angeles, California, USA
S. Corde, A. Doche
LOA, Palaiseau, France
W. Lu
TUB, Beijing, People's Republic of China

Funding: Work supported by DOE contract DE-AC02-76SF00515.
Over the past decade, there has been enormous progress in the field of beam and laser-driven plasma acceleration of electron beams. However, in order for plasma wakefield acceleration to be useful for a high-energy e⁺e^- collider, we need a technique for accelerating positrons in plasma as well. This is a unique challenge, because the plasma responds differently to electron and positron beams, with plasma electrons being pulled through the positron beam and creating a non-linear focusing force. Here, we demonstrate a technique called hollow channel acceleration that symmetrizes the wakefield response to beams of either charge. Using a transversely shaped laser pulse, we create an annular plasma with a fixed radius of 200 μm. We observe the acceleration of a positron bunch with energies up to 33.4 MeV in a 25 cm long channel, indicating an effective gradient greater than 100 MeV/m. This is the first demonstration of a technique that way be used for staged acceleration of positron beams in plasma.

Slides THPPA01 [5.647 MB]

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THPMB008

Compensation of Steerer Crosstalk between FLASH1 and FLASH2

betatron, electron, 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.

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THPMB026

Research on Low Secondary Electron Yield Materials for Future Accelerators

electron, vacuum, 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.

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THPMB027

Beam Transport Line of the LPA-FEL Facility Based on Transverse Gradient Undulator

FEL, undulator, radiation, beam-transport

3287

T. Liu, B. Liu, D. Wang, T. Zhang
SINAP, Shanghai, People's Republic of China
Z. Huang
SLAC, Menlo Park, California, USA
J.S. Liu
Shanghai Institute of Optics and Fine Mechanics, Shanghai, People's Republic of China

Free electron lasers (FELs) based on Laser Plasma Accelerators (LPAs) present a main research direction for achieving next generation compact advanced light sources. There are several major challenges of the LPA beam to generate high-brilliance FEL radiation including the large initial angular divergence and the large energy spread. Based on the LPA facility in SIOM that has successfully obtained quasi-monochromatic beam with the central energy of hundreds of MeV, a specific design of a beam transport line is proposed to realize FEL gain using Transverse Gradient Undulator to compensate the relatively large beam energy spread. This beamline uses a single dipole, several strong focusing quadrupoles and correcting sextupoles to match proper beta functions and linear dispersion from the LPA beam to FEL radiation. The corresponding experimental facility of LPA-FEL in SIOM has been set up and will perform first tests to generate FEL radiation.

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THPMB040

Charged Particle Transport, Gaussian Optics, Error Propagation: It's all the Same

optics, emittance, beam-transport, electron

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.

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THPMR004

Design of a Compact ion Beam Transport System for the BELLA Ion Accelerator

ion, target, quadrupole, proton

3391

Q. Ji, S.S. Bulanov, E. Esarey, W. Leemans, T. Schenkel, S. Steinke
LBNL, Berkeley, California, USA

Funding: This work was supported by LDRD funding from Lawrence Berkeley National Lab, provided by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The Berkeley Lab Laser Accelerator (BELLA) Center hosts a Ti:sapphire CPA laser providing laser pulses at petawatt-level peak power with a repetition rate of 1 Hz. High irradiances of 10²² W/cm² can be achieved with a short focal length beamline when the laser is focused to a spot of w₀ < 5 um. Under this condition, theoretical and particle-in-cell (PIC) simulations have shown that protons and helium ions at energies up to several hundred MeV/u can be expected from the interaction between BELLA laser pulses and different targets. High ion energies*, low energy spread with high controllability and stability, a new generation of ion accelerators using high performance laser-driven ion beam has numerous potential applications such as injectors for conventional accelerators, radiation therapy, as well as high energy density laboratory physics and material science studies. We will present a preliminary ion optics design to collect, transport, and focus the ions generated from the laser-driven ion accelerator, and beam dynamics results using the ion distribution from the PIC simulation.
* S.S. Bulanov et al, Physical Review Special Topics: Accelerators and Beams 18, 061302 (2015).

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THPMW041

Single Crystal Diamond X-ray Lens Development

optics, synchrotron, storage-ring, electron

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).

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THPMY001

Design and R&D for the SPring-8 Upgrade Storage Ring Vacuum System

vacuum, photon, storage-ring, radiation

3651

M. Oishi, T. Bizen, H. Ohkuma, M. Shoji, S. Takahashi, K. Tamura, Y. Taniuchi
JASRI/SPring-8, Hyogo-ken, Japan

Conceptual design report for the SPring-8 upgrade project (SPring-8-II) was published in November of 2014. Vacuum system for the targeted storage ring should handle some fateful boundary conditions, such as miniaturization of vacuum chamber and increase in number of photon absorbers resulting from the multi-bend achromat configuration. Furthermore, reuse of the existing tunnel brings the severe packing factor issue of vacuum components and the time constraints issue of one-year blackout. Considering the above circumstances, a concept of 12-m long vacuum chamber with welded integral structure was proposed to omit in-situ baking. The 12-m long chamber will be evacuated to ultra-high vacuum by ex-situ baking followed by NEG activation, and moved to the tunnel with special thin gate valves at both ends. Recently, the chamber material has been changed from aluminum alloy to stainless steel (SS) from the viewpoints of elimination of aluminum-SS transition space, beam vibration suppression, and superior outgassing property. Trial production of SS chamber is proceeding to establish appropriate manufacturing processes, while focusing on the accuracy of dimension and magnetic permeability.

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THPMY013

Laser-Beam Welding for a TPS Beam-Position Monitor

interface, controls, vacuum, target

3679

Y.T. Huang, C.-C. Chang, J.-R. Chen, G.-Y. Hsiung, S-N. Hsu
NSRRC, Hsinchu, Taiwan

The TPS beam-position monitor has two feedthroughs in one flange structure. The hermetic seal was formed with laser-beam welding (LBW). Nd-YAG LBW was adopted to weld a button electrode with a feedthrough; CO2 LBW served for a feedthrough and a flange, Fig. 1. A robotic arm was used for Nd-YAG LBW so that it could accomplish the complicated geometry of the welded joint. Although the CO2 laser was not coordinated with a robotic arm, fixtures were made to implement a circular welded joint the same as welding the feedthrough into a flange. For not only Nd-YAG but also CO2 LBW, the cover gas is the major key that avoids oxidation from atmospheric oxygen and maintains shiny weld beads. Taguchi methods were exploited to find the appropriate parameters for the Nd-YAG pulsed laser, for instance, the laser power, pulse-filling time, frequency etc.. This paper presents the process and details of laser-beam welding of two types for a beam-position monitor.
Laser beam weld, Nd-YAG, CO2, POWER, filling time, beam position monitor

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THPMY017

A Comparison of Surface Properties of Metallic Thin Film Photocathodes

electron, 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.

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THPMY029

Technical Overview of the PAL-XFEL Low-Conductivity Water Cooling System

controls, simulation, operation, ion

3718

B.H. Lee, H.-G. Kim, K.W. Kim, K.R. Kim, S.H. Kim, Y. C. Kim, H.M. Lee, M.S. Lee, H. Matsumoto, I. Mok, C.W. Sung, J. Yang
PAL, Pohang, Kyungbuk, Republic of Korea
J.H. Jeon
Taeyoung, Seoul, Republic of Korea
K.T. Kim
HMT, Pohang, Republic of Korea
I.S. Ko
POSTECH, Pohang, Kyungbuk, Republic of Korea

Pohang Accelerator Laboratory (PAL) started operation of an X-ray Free Electron Laser (XFEL) based on 10GeV linear accelerator in FY2015. For accurate temperature control of the various XFEL accelerator devices, a low-conductivity water (LCW) cooling system were installed. The LCW pump station generates LCW controlling the temperature variation within ±0.1°C. The LCW is supplied to klystrons including modulators and various control devices. On the other hand, the precision temperature controlled water to minimize temperature variation down to ±0.02°C. This water is supplied to accelerating columns, wave guide and SLED. Therefore, this paper shows the design, construction and operation of the LCW cooling system.

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THPMY039

RF Synchronization and Distribution for AWAKE at CERN

proton, electron, 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.

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THPMY040

Laser Cooling of Relativistic Highly Charged Ions at FAIR

ion, detector, synchrotron, vacuum

3747

D.F.A. Winters, O. Boine-Frankenheim, L. Eidam, T. Kühl, P.J. Spiller, T. Stöhlker
GSI, Darmstadt, Germany
T. Beck, G. Birkl, D. Kiefer, T. Walther
TU Darmstadt, Darmstadt, Germany
M.H. Bussmann, U. Schramm, M. Siebold
Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany
V. Hannen, D. Winzen
Westfälische Wilhelms-Universität Münster, Institut für Kernphysik, Münster, Germany
M. Löser
HZDR, Dresden, Germany
X. Ma, W.Q. Wen
IMP/CAS, Lanzhou, People's Republic of China

An overview of recent laser cooling activities with relativistic heavy ion beams at the ESR (GSI, Darmstadt, Germany) and the CSRe (IMP, Lanzhou, China) storage rings will be presented. Some of the latest results will be shown and new developments concerning xuv-detector systems and cw and pulsed laser systems will be addressed. Finally, plans for laser cooling (& spectroscopy) at the future facility FAIR in Darmstadt will be presented, focusing on the SIS100.

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THPMY041

Neodymium and Ytterbium Hybrid Solid Laser of RF Gun for SuperKEKB

cavity, electron, 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.

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THPMY042

Laser Applications at Accelerators

network, electron, 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.

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THPOW003

Highlights on Metallic Photocathodes Used in SRF Gun

gun, cathode, SRF, emittance

3928

R. Xiang, A. Arnold, P.N. Lu, P. Michel, P. Murcek, J. Teichert, H. Vennekate
HZDR, Dresden, Germany
P.N. Lu, H. Vennekate
TU Dresden, Dresden, Germany

For the accelerator-based light sources and the electron colliders, the development of photoinjectors has become a key technology. Especially for the superconducting radio frequency cavity based injector (SRF Gun), the searching for better photocathodes is always a principal technical challenge. To use metallic photocathodes for ELBE SRF Gun is the primary choice to prevent cavity contamination. In this contribution, we will report the investigation of Magnesium (Mg) in ELBE SRF gun, including laser cleaning treatment and the measurement on quantum efficiency, Schottky effect, dark current and damage threshold.
The work is supported by the European Community under the FP7 programme (EuCARD-2 and LA3NET) and by the German Federal Ministry of Education and Research (BMBF) grant 05K12CR1.

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THPOW004

Pulse Response Measurements of NEA Photocathodes at Different Laser Wavelengths

electron, 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.

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THPOW005

A Study of CsK2Sb Multi-alkali Photocathode by Ultraviolet Photoelectron Spectroscopy at UVSOR

cathode, electron, 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.

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THPOW006

A Study of Operational Lifetime of CsK2Sb Photo-cathode

cathode, vacuum, electron, 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.

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THPOW007

Cs2Te Photocathode Response Time Measurements and Femtosecond Comb Electron Beam Generation as a Milestone Towards Pre-Bunched Thz Fel Realization

electron, radiation, 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.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW007

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THPOW009

Optimal Design of a Photocathode Electron Gun with High-brightness and High-repetition Rate Based on Genetic Algorithm

gun, impedance, electron, cavity

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.

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THPOW015

Study of the Performance of Cs2Te Cathodes in the PHIN RF Photoinjector using Long Pulse Trains

cathode, vacuum, operation, electron

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.

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THPOW016

Transverse Energy Spread Measurements from GaAs Photocathodes at Variable Wavelengths

electron, cathode, detector, 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.

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THPOW020

S-Band Photoinjector Investigations by Multiobjective Genetic Optimizer

emittance, brightness, gun, cathode

3979

H.J. Qian, D. Filippetto, F. Sannibale
LBNL, Berkeley, California, USA

Photoinjectors has witnessed great progress in the past few decades, with low duty cycle high gradient guns, such as normal conducting S/L band gun, pushing the peak beam brightness frontier, and CW guns, such as DC gun, SRF gun and VHF gun, pushing the average beam brightness frontier. Due to different degrees of complexity, pulsed high gradient photoinjectors are usually optimized by manual scans, while CW photoinjectors are optimized by multi-objective genetic optimizers. In this paper, a multi-objective genetic optimizer is used to revisit S-band photoinjector beam brightness optimizations, showing a trade-off between peak current and transverse emittance, with the optimized injector layout depending on bunch charge and peak current. For 200 pC case, the final beam core brightness at injector exit is close to cathode maximum brightness in the 'cigar beam' regime. Assuming a thermal emittance of 0.5 μm/mm and a beam charge of 200 pC, about 90 nm slice emittance at 20 A peak current is achieved.

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THPOW021

Generation of Homogeneous and Patterned Electron Beams using a Microlens Array Laser-Shaping Technique

electron, 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.

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THPOW023

Intrinsic Emittance Reduction in Transmission Mode Photocathodes

electron, emittance, scattering, 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.

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THPOW026

LLNL X-band RF Gun Results

electron, 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.

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THPOW027

Compact X-band Accelerator Controls for a Laser-Compton X-ray Source

controls, LabView, interface, timing

3996

D.J. Gibson, G.G. Anderson, C.P.J. Barty, R.A. Marsh
LLNL, Livermore, California, USA

Funding: This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
LLNL's compact, tunable, laser-Compton x-ray source has been built around an advanced X-band photogun and accelerator sections and two independent laser systems. In support of this source, a complete integrated control system has been designed and built from scratch to provide access to the critical control points and continues to grow to simplify operation of the system and to meet new needs of this research capability. In addition to a PLC-based machine protection component, a custom, LabView-based suite of control software monitors systems including low level and high power RF, vacuum, magnets, and beam imaging cameras. This system includes a comprehensive operator interface, automated and expandable arc detection to optimize rf conditioning of the high-gradient structures, and automated quad-scan-based emittance measurements to explore the beam tuning parameter space. An overview of this system is presented, including the latest upgrades to FPGA-based hardware for the RF system controls.

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THPOW030

ELI Eectron Beam Line for Laser-plasma-driven Undulator X-ray Source

electron, undulator, quadrupole, 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.

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THPOW042

Start-to-End Simulation on Terahertz Superradiation of Ultrashort Electron Bunch in an Undulator

radiation, undulator, simulation, electron

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.

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THPOW045

Development of PAL-XFEL Undulator System

undulator, FEL, electron, 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.

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THPOW054

Cumulative Damage of Ultrafast Laser Pulses

vacuum, experiment, site, electron

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.

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THPOW056

Fiber Laser Development for Dielectric Laser-driven Accelerator and Electron Beam Source

electron, 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)

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THPOW057

Direct High Power Laser Diagnostic Technique on Focused Electron Bunch

electron, 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.

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THPOW058

Drive Laser System for the DC-SRF Photoinjector at Peking University

SRF, electron, 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.

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THPOW059

UV Pulse Shaping with a-BBO Crystals for the Photocathode RF Gun

electron, 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.

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THPOY003

The Turn-key Control System for the ELI-NP Gamma Beam System

controls, EPICS, timing, electron

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.

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THPOY052

Current Status of HES (Hard X-ray EndStation)-2 Beamline at PAL-XFEL

detector, focusing, optics, diagnostics

4225

S. Kim, B. Kim, K.H. Nam, J. Park
PAL, Pohang, Republic of Korea

HES (Hard X-ray EndStation)-2 beamline is located at the hard X-ray experimental hall at PAL-XFEL. The main objective of HES-2 beamline is to deliver a hard X-ray FEL beam to target materials in such a manner that a coherent diffraction study is possible. This endstation is supposed to provide brilliant hard x-rays and to measure the diffraction patterns with forward scattering geometry. In particular, the instruments are designed for serial femtosecond X-ray crystallography (SFX) and coherent diffraction imaging (CDI). In this poster, we introduce HES-2 beamline at PAL-XFEL in terms of two perspectives: beamline instrumentation and sample environment. In the instrumentation part, the current status of HES-2 beamline is described in details. This includes beamline layout, x-ray optics, beam diagnositics and the upcoming commissioning plan for HES-2 beamline. In the sample environment part, we aim to present scientific goals based on the sample environments for CXI and SFX respectively. Finally, we discuss the feasible demo-experiments, which is expected to be done in 2016.

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THPOY054

An External Synchronization of PHIL to a High Power Femtosecond Laser

electron, 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.

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THPOY057

RF Timing Distribution and Laser Synchronization Commissioning of PAL-XFEL

timing, linac, LLRF, FEL

4234

C.-K. Min, S.H. Jung, H.-S. Kang, C. Kim, I.S. Ko, S.J. Park
PAL, Pohang, Kyungbuk, Republic of Korea

PAL-XFEL requires <100 fs synchronization of LLRF systems and optical lasers for stable operation and even lower jitter is favorable in higher performance and pump-probe experiments. The RF timing distribution system is based on a 476 MHz reference line, which is converted to 2.856 GHz at 16 locations over 1.5 km distance using phase-locked DRO. The 2.856 GHz signals are amplified and split to 10 outputs, which is connected to LLRFs, BAMs, and DCMs through low timing drift cables. The jitter between two different PLDRO units is estimated to ~1 fs from 1 Hz to 1 MHz. The synchronization jitter between a Ti:sapphire laser and the 2.856 GHz signal is measured less than 20 fs.

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THPOY059

Synchronization System for Tsinghua Thomson Scattering X-ray Source

controls, LLRF, scattering, low-level-rf

4237

J. Yang, Y.-C. Du, W.-H. Huang, D. Wang, L.X. Yan
TUB, Beijing, People's Republic of China
J.M. Byrd, L.R. Doolittle, Q. Du, G. Huang, R.B. Wilcox, Y.L. Xu
LBNL, Berkeley, California, USA

Tsinghua Thomson scattering X-ray Source (TTX) generates X-ray based on inverse thomson scattering method. The synchronization system for TTX includes reference distribution, normal conducting cavity Low Level RF control and Laser-RF synchronization. In collaboration with LBNL, we're working on a prototype synchronization system for TTX. Some test result based on Tsinghua Thomson scattering X-ray Source were obtained. In this paper we will show the synchronization system design and preliminary test result.

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THPOY060

Four Beam Generation for Simultaneous Four-Hall Operation at CEBAF

timing, electron, 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.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY060

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FRXBB01

Achieved Performance of an All X-band Photo-injector

gun, cathode, electron, 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]

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-FRXBB01

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FRXCB01

Two Beam Wakefield Acceleration at Argonne Wakefield Accelerator Facility

wakefield, acceleration, experiment, electron

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]

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-FRXCB01

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