IPAC2014 - List of Keywords (electron)

Paper	Title	Other Keywords	Page
MOYAA01	Innovative Ideas for Single-pass FELs	FEL, operation, undulator, photon	12
	T. Hara RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
	SASE FELs are a powerful light source in short wavelengths from VUV to X-ray regions to investigate matters and phenomena. SASE was first experimentally obtained in 2000 at DESY TTF with an output wavelength of 10⁹ nm. Subsequently, FLASH, LCLS and SACLA have achieved lasing in VUV, soft X-rays and hard X-rays. Although SASE has already been widely used for many application experiments in broad scientific fields, its spiky spectrum and time structures due to the lack of longitudinal coherence sometimes become problematic. To improve its longitudinal coherence, various ideas have been proposed and some of them are already demonstrated experimentally, such as a self-seeded scheme, high-gain harmonic generation (HGHG) and echo-enabled harmonic generation (EEHG). There is also another direction of developments to enhance the capability and potentiality of SASE, for example short pulse generation and two-color lasing. This talk will review recent innovative ideas of short wavelength FELs together with their experimental results.
	Slides MOYAA01 [10.701 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOYAA01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOZB02	Advances in Photocathodes for Accelerators	emittance, cathode, laser, experiment	48
	L. Cultrera Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	This talk reviews advances in photocathode technology for accelerators: cathodes demonstrating record average currents and deliverable charge, possessing ultra-low intrinsic emittance and sub-picosecond response time. It addresses the grand challenge to combine all these useful properties into a single photoemitter - one that is being actively pursued by the research community.
	Slides MOZB02 [4.354 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOZB02
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO001	Upgrade Status of Injector LINAC for SuperKEKB	positron, linac, emittance, gun	59
	T. Miura, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, Y. Funakoshi, K. Furukawa, T. Higo, H. Honma, R. Ichimiya, N. Iida, M. Ikeda, E. Kadokura, H. Kaji, K. Kakihara, T. Kamitani, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, F. Miyahara, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, Y. Ohnishi, S. Ohsawa, F. Qiu, M. Satoh, T. Shidara, A. Shirakawa, H. Sugimoto, T. Suwada, T. Takenaka, M. Tanaka, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou KEK, Ibaraki, Japan D. Satoh TIT, Tokyo, Japan
	The SuperKEKB collider is under construction to achieve 40-times higher luminosity than that of previous KEKB collider. The injector LINAC should provide high-intensity and low-emittance beams of 7-GeV electron and 4-GeV positron for SuperKEKB based on a nano-beam scheme. A photocathode RF-gun for low emittance electron beam has been already installed and the commissioning has started. The construction of positron capture section using a flux-concentrator and the dumping ring for low emittance positron beam is in progress. The simultaneous top-up injections to four storage-rings including photon factories is also required. In the upstream of dumping ring, the compatible optics between positron and electron has been designed. In the downstream of dumping ring, RF phase, focusing, and steering magnets will be switched by pulse to pulse against each beam-mode for optimising beam-transportation. This paper describes recent upgrade status toward the SuperKEKB.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO001
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO003	Towards Stable Acceleration in Linacs	klystron, acceleration, bunching, linac	65
	A. Dubrovskiy Private Address, Geneve, Switzerland
	Ultra-stable and -reproducible high-energy particle beams with short bunches are needed in novel linear accelerators and, in particular, in the Compact Linear Collider CLIC. A passive beam phase stabilization system based on a bunch compression with a negative transfer matrix element R56 and acceleration at a positive off-crest phase is proposed. The motivation and expected advantages of the proposed scheme are outlined.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO003
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO005	Progress on the Interaction Region Design and Detector Integration at JLab’s MEIC	detector, ion, collider, focusing	71
	V.S. Morozov, P.D. Brindza, A. Camsonne, Y.S. Derbenev, R. Ent, D. Gaskell, F. Lin, P. Nadel-Turonski, M. Ungaro, Y. Zhang, Z.W. Zhao JLab, Newport News, Virginia, USA C. Hyde, K. Park Old Dominion University, Norfolk, Virginia, USA M.K. Sullivan SLAC, Menlo Park, California, USA Z.W. Zhao UVa, Charlottesville, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357. One of the unique features of JLab's Medium-energy Electron-Ion Collider (MEIC) is a full-acceptance detector with a dedicated, small-angle, high-resolution detection system, capable of covering a wide range of momenta (and charge-to-mass ratios) with respect to the original ion beam to enable access to new physics. We present an interaction region design developed with close integration of the detection and beam dynamical aspects. The dynamical aspect of the design rests on a symmetry-based concept for compensation of non-linear effects. The optics and geometry have been optimized to accommodate the detection requirements and to ensure the interaction region's modularity for ease of integration into the collider ring lattices. As a result, the design offers an excellent detector performance combined with the necessary provisions for non-linear dynamical optimization.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO005
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO006	Preservation of Electron Polarization in the MEIC Collider Ring	polarization, collider, injection, solenoid	74
	F. Lin, Y.S. Derbenev, V.S. Morozov, Y. Zhang JLab, Newport News, Virginia, USA D.P. Barber DESY, Hamburg, Germany
	Funding: U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357. A highly longitudinally-polarized (over 70%) electron beam is required by the nuclear physics programme of the Medium Energy Electron-Ion Collider (MEIC) at Jefferson Lab (JLab). To achieve this goal, a highly vertically-polarized electron beam is injected from the CEBAF. The polarization will be vertical in the arcs to avoid spin diffusion, and longitudinal at the collision points. The polarization rotation will be accomplished by using a total of four spin rotators, each of which consists of a set of solenoids and dipoles, placed at the ends of two arcs. The polarization configuration cancels the 1st order spin perturbation in the solenoids for the off-momentum particles and significantly reduces the synchrotron sideband resonances. In order to compensate the net Sokolov-Ternov depolarization effect, especially at higher energies, a continuous injection of a polarized electron beam from the CEBAF is being considered. We consider to perform a moderate spin matching in some key regions to extend the polarization lifetime so that the continuous injection can work more efficiently, while not imposing a burden on the optics design of the collider ring.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO006
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO007	GPU-Accelerated Long-Term Simulations of Beam-Beam Effects in Colliders	GPU, luminosity, simulation, collider	77
	B. Terzić, F. Lin, V.S. Morozov, Y. Roblin, H. Zhang JLab, Newport News, Virginia, USA M. Aturban, D. Ranjan, M. Zubair ODU CS, Norfolk, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. We present an update on the development of the new code for long-term simulation of beam-beam effects in particle colliders. The underlying physical model relies on a matrix-based arbitrary-order particle tracking (including a symplectic option) for beam transport and the generalized Bassetti-Erskine approximation for beam-beam interaction. The computations are accelerated through a parallel implementation on a hybrid GPU/CPU platform. With the new code, previously computationally prohibitive long-term simulations become tractable. The new code will be used to model the proposed Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO007
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO011	Employing Twin Crabbing Cavities to Address Variable Transverse Coupling of Beams in the MEIC*	solenoid, proton, cavity, coupling	80
	A. Castilla DCI-UG, León, Mexico A. Castilla, J.R. Delayen, V.S. Morozov, T. Satogata JLab, Newport News, Virginia, USA A. Castilla, J.R. Delayen, V.S. Morozov, T. Satogata ODU, Norfolk, Virginia, USA
	Funding: *Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The design strategy of the Medium Energy Electron-Ion Collider (MEIC) at Jefferson Lab contemplates both matching of the emittance aspect ratios and a 50 mrad crossing angle along with crab crossing scheme for both electron and ion beams over the energy range (√s=20-70 GeV) to achieve high luminosities at the interaction points (IPs). However, the desired locations for placing the crabbing cavities may include regions where the transverse degrees of freedom of the beams are coupled with variable coupling strength that depends on the collider rings’ magnetic elements (solenoids and skew quadrupoles). In this work we explore the feasibility of employing twin rf dipoles that produce a variable direction crabbing kick to account for a range of transverse coupling of both beams.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO011
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO012	Simulating Fast Beam-Ion Instability Studies in FFAG-Based ERHIc Rings	ion, simulation, linac, lattice	83
	G. Wang, V. Litvinenko, Y. Luo 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. In an electron accelerator, ions generated from the residual gas by the circulating electrons act back to the trailing electrons. Under unfavorable conditions this feed-back can cause unstable motion of the electron bunches, the process known as the fast beam ion instability. Current eRHIC design has two FFAG rings transporting 21 electron beams at 11 different energies. In this study, we use numerical simulation to investigate the fast ion instability in this complicated system, compare the simulation results with theory and discuss possible measures to mitigate the instability.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO012
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO013	Present Status of Coherent Electron Cooling Proof-of-Principle Experiment	ion, cavity, gun, experiment	87
	V. Litvinenko, Z. Altinbas, D.R. Beavis, S.A. Belomestnykh, I. Ben-Zvi, K.A. Brown, J.C. Brutus, A.J. Curcio, L. DeSanto, C. Folz, D.M. Gassner, H. Hahn, Y. Hao, C. Ho, Y. Huang, R.L. Hulsart, M. Ilardo, J.P. Jamilkowski, Y.C. Jing, F.X. Karl, D. Kayran, R. Kellermann, N. Laloudakis, R.F. Lambiase, G.J. Mahler, M. Mapes, W. Meng, R.J. Michnoff, T.A. Miller, M.G. Minty, P. Orfin, A. Pendzick, I. Pinayev, F. Randazzo, T. Rao, J. Reich, T. Roser, J. Sandberg, T. Seda, B. Sheehy, J. Skaritka, L. Smart, K.S. Smith, L. Snydstrup, A.N. Steszyn, R. Than, C. Theisen, R.J. Todd, J.E. Tuozzolo, E. Wang, G. Wang, D. Weiss, M. Wilinski, T. Xin, W. Xu, A. Zaltsman BNL, Upton, Long Island, New York, USA G.I. Bell, J.R. Cary, K. Paul, I.V. Pogorelov, B.T. Schwartz, A.V. Sobol, S.D. Webb Tech-X, Boulder, Colorado, USA C.H. Boulware, T.L. Grimm, R. Jecks, N. Miller Niowave, Inc., Lansing, Michigan, USA A. Elizarov SUNY SB, Stony Brook, New York, USA M.A. Kholopov, P. Vobly BINP SB RAS, Novosibirsk, Russia P.A. McIntosh, A.E. Wheelhouse STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: Work supported by Stony Brook University and by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The Coherent Electron Cooling Proof of Principle (CeC PoP) system is being installed in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. It will demonstrate the ability of relativistic electrons to cool a single bunch of heavy ions in RHIC. This technique may increase the beam luminosity by as much as tenfold. Within the scope of this experiment, a 112 MHz 2 MeV Superconducting Radio Frequency (SRF) electron gun coupled with a cathode stalk mechanism, two normal conducting 500 MHz single-cell bunching cavities, a 704 MHz 20 MeV 5-cell SRF cavity and a helical undulator will be used. In this paper, we provide an overview of the engineering design for this project, test results and discuss project status and plansd.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO013
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO015	Advances in Coherent Electron Cooling	hadron, FEL, bunching, kicker	91
	V. Litvinenko, Y. Hao, Y.C. Jing, D. Kayran, G. Wang BNL, Upton, Long Island, New York, USA G.I. Bell, I.V. Pogorelov, B.T. Schwartz, A.V. Sobol, S.D. Webb Tech-X, Boulder, Colorado, USA D.L. Bruhwiler RadiaSoft LLC, Boulder, Colerado, USA A. Elizarov SUNY SB, Stony Brook, New York, USA D.F. Ratner SLAC, Menlo Park, California, USA O.A. Shevchenko BINP SB RAS, Novosibirsk, Russia
	This paper will be focused on advances and challenges in cooling of high-energy hadron – and potentially heavy lepton-beams. Such techniques are required to improve quality of hadron beams and for increasing the luminosity in hadron and electron-hadron colliders. In contrast with light leptons, which have very strong radiation damping via synchrotron radiation, the hadrons radiate very little (even in 7TeV LHC) and require additional cooling mechanism to control growth of their emittances. I will discuss the physics principles of revolutionary, but untested, technique: the coherent electron cooling (CeC). Further, current advances and novel CeC schemes will be presented as well as the status of preparation at Brookhaven National Laboratory for the CeC demonstration experiment.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO015
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO024	The Beam Test for the Ti Extraction Window Damage	extraction, experiment, radiation, kicker	119
	T. Mimashi, N. Iida, M. Kikuchi KEK, Ibaraki, Japan
	For the SuperKEKB beam abort system, the Ti extraction window will be used. The damage of the extraction window was estimated with KEKB electron beam. Thin Ti plate and Ti alloy plate were tested as candidates of extraction window material. The damages were observed as a function of beam current. From this experiment, the maximum charge density at the extraction window is determined.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO024
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO036	Beam Life Time and Stability Studies for ELENA	antiproton, emittance, simulation, vacuum	154
	J. Resta-López, O. Karamyshev, D. Newton, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom O. Karamyshev, D. Newton, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom J. Resta-López IFIC, Valencia, Spain
	Funding: Work supported by the EU under Grant Agreement 624854 and the STFC Cockcroft Institute Core Grant No. ST/G008248/1. The Extremely Low ENergy Antiproton ring (ELENA) is a small synchrotron equipped with an electron cooler, which shall be constructed at CERN to decelerate antiprotons to energies as low as 100 keV. At such low energies it is very important to carefully take contributions from electron cooling and heating effects (e.g. on the residual gas) into account. Detailed investigations into the ion kinetics under consideration of effects from electron cooling and scattering on the residual gas have been carried out using the BETACOOL code. In this contribution a consistent explanation of the different physical effects acting on the beam in ELENA is given. Beam lifetime, equilibrium momentum spread and emittance are all estimated based on numerical simulations. Finally, optimum machine settings are presented as a result of optimization studies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO036
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO054	Commissioning progress of the Femto-slicing Project at SOLEIL	laser, wiggler, radiation, synchrotron	206
	M. Labat, H.B. Abualrob, P. Betinelli-Deck, A. Buteau, N. Béchu, L. Cassinari, M.-E. Couprie, F. Dohou, C. Herbeaux, Ph. Hollander, J.-F. Lamarre, C. Laulhé, A. Lestrade, J. Lüning, O. Marcouillé, J.L. Marlats, T. Moreno, P. Morin, A. Nadji, L.S. Nadolski, D. Pédeau, P. Prigent, S. Ravy, J.P. Ricaud, M. Ros, P. Roy, M.G. Silly, F. Sirotti, K. Tavakoli, M.-A. Tordeux, D. Zerbib SOLEIL, Gif-sur-Yvette, France
	The femtoslicing project at SOLEIL is currently under commissioning. It will enable to serve several beamlines with 100 fs FWHM long pulses of soft and hard X-rays with reasonable flux and with a 1 kHz repetition rate. It is based on the interaction of a femtosecond Ti:Sa laser with electrons circulating in the magnetic field of a modulator wiggler, that provides the electron beam energy modulation on the length scale of the laser pulse. The optimization of the interaction is performed using two dedicated diagnostics stations. The first one, operating in the Infra-Red (IR) is installed in the tunnel and allows the adjustment of the temporal, spectral and spatial overlap between the laser and the electron beam. The second one, located in the IR-THz AILES beamline, measures the intensity of the terahertz (THz) radiation emitted by the local dip structure produced in the core electron beam after interaction. This second setup provides refined optimization of the interaction. This paper describes the layout of these diagnostics and gives first results and characterization of the slicing experiment at SOLEIL.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO054
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO061	Study of the Beam Lifetime at the Synchrotron Light Source DELTA	scattering, synchrotron, vacuum, simulation	222
	M.A. Jebramcik, H. Huck, S. Khan, R. Molo DELTA, Dortmund, Germany
	DELTA is a 1.5-GeV synchrotron light source operated by the TU Dortmund University. The beam lifetime, which is a critical issue for user operation of a light source, was studied experimentally and by simulation for different operation modes, i.e. single-bunch and multibunch fill patterns and for different beam currents. The electron loss rate is dominated by residual-gas scattering (Coulomb scattering and Bremsstrahlung) and by electron-electron scattering (Touschek effect). Since these processes depend in different ways on the momentum acceptance of the storage ring, a variation of the RF cavity voltage allows to disentangle their respective contributions to the total loss rate. The experimental results lead to a consistent picture for different operation modes with a characteristic dependence of the residual-gas pressure on the beam current.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO061
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO066	Status of FLUTE	laser, gun, linac, diagnostics	231
	M. Schuh, I. Birkel, A. Borysenko, A. Böhm, N. Hiller, E. Huttel, S. Höninger, V. Judin, S. Marsching, A.-S. Müller, A.-S. Müller, A.-S. Müller, S. Naknaimueang, M.J. Nasse, R. Rossmanith, R. Ruprecht, M. Schwarz, M. Weber, P. Wesolowski KIT, Karlsruhe, Germany R.W. Aßmann, M. Felber, K. Flöttmann, M. Hoffmann, H. Schlarb DESY, Hamburg, Germany H.-H. Braun, R. Ganter, V. Schlott, L. Stingelin PSI, Villigen PSI, Switzerland
	FLUTE, a new linac-based test facility and THz source is currently being built at the Karlsruhe Institute of Technology (KIT) in collaboration with DESY and PSI. It consists of an RF photo gun and a traveling wave linac accelerating electrons to beam energies of ~41 MeV in the charge range from a few pC up to 3 nC. The electron bunch will then be compressed in a magnetic chicane in the range of 1 - 300 fs, depending on the charge, in order to generate coherent THz radiation with high peak power. An overview of the simulation and hardware status is given in this contribution.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO066
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO067	Analytic Calculation of Electric Fields of Coherent THz Pulses	radiation, synchrotron, synchrotron-radiation, shielding	234
	M. Schwarz, P. Basler, M. Guenther, A.-S. Müller, M. von Borstel KIT, Karlsruhe, Germany M.T. Schmelling MPI-K, Heidelberg, Germany
	The coherently emitted electric field pulse of a short electron bunch is obtained by summing the fields of the individual electrons, taking phase differences due to different longitudinal positions into account. For an electron density, this sum becomes an integral over the charge density and frequency spectrum of the emitted radiation, which, however, is difficult to evaluate numerically. In this paper, we present a fast analytic method valid for arbitrary bunch shapes. We also include shielding effects of the beam pipe and consider ultra-short bunches, where the high frequency part of the coherent synchrotron spectrum is cut-off not by the inverse bunch length but by the critical frequency of synchrotron radiation. Our technique is applied to bunches, simulated simulated for the linac-based FLUTE accelerator test facility at KIT.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO067
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO073	Design of Iranian Light Source Facility RF Shielded Bellows	impedance, vacuum, storage-ring, wakefield	252
	H. Ghasem IPM, Tehran, Iran J. Etemad Moghadam ILSF, Tehran, Iran
	Total impedance is one of the most effective parameters for proper operation of an accelerator system. This quantity is evaluated with the summation of individual component impedance of the vacuum pipe and is desired to be as low as possible. The bellows have very significant effects on total impedance of the accelerator systems particularly synchrotron light source storage rings. Design of the bellow for Iranian Light Source Facility (ILSF) with a practical approach for fabrication has been down. Minimization of the total impedance budget, loss factor and the resulting wake field due to the passage of 400 mA electron beam is the main goal of our design.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO073
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO078	The SPARC_LAB Thomson Source Commissioning	laser, photon, linac, emittance	267
	C. Vaccarezza, D. Alesini, M.P. Anania, M. Bellaveglia, E. Chiadroni, D. Di Giovenale, G. Di Pirro, M. Ferrario, A. Gallo, G. Gatti, R. Pompili, S. Romeo, F. Villa INFN/LNF, Frascati (Roma), Italy A. Bacci, C. Curatolo, D.T. Palmer, V. Petrillo, A.R. Rossi, L. Serafini, P. Tomassini Istituto Nazionale di Fisica Nucleare, Milano, Italy P. Cardarelli, G. Di Domenico, M. Gambaccini INFN-Ferrara, Ferrara, Italy A. Cianchi INFN-Roma II, Roma, Italy P. Delogu INFN-Pisa, Pisa, Italy F. Filippi, A. Giribono INFN-Roma, Roma, Italy B. Golosio, P. Oliva INFN-Cagliari, Monserrato (Cagliari), Italy A. Mostacci Rome University La Sapienza, Roma, Italy
	The SPARC_LAB Thomson source is presently under commissioning at LNF. An electron beam of energy between 30-150 MeV collides head-on with the laser pulse provided by the Ti:Sapphire laser FLAME, characterized in this phase by a length of 6 ps FWHM and by an energy ranging between 1 and 5 J. The key features of this system are the wide range of tunability of the X-rays yield energy, i.e. 20-500 keV, and the availability of a coupled quadrupole and solenoid focusing system, allowing to reach an electron beam size of 10-20 microns at the interaction point. The experimental results obtained in the February 2014 shifts are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO078
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO083	Design Study of High Brilliant Optics at the SPring-8 Storage Ring	emittance, photon, brilliance, optics	283
	Y. Shimosaki, T. Aoki, K. Fukami, K.K. Kaneki, K. Kobayashi, M. Masaki, C. Mitsuda, H. Ohkuma, M. Shoji, K. Soutome, S. Takano, M. Takao JASRI/SPring-8, Hyogo-ken, Japan
	At the SPring-8 storage ring, design study of beam optics concentrating particularly on increasing brilliance, not flux density, is in progress besides continuous efforts of increasing both brilliance and flux density for the user optics. The natural emittances are theoretically reduced from 2.41 nmrad at 8 GeV to 2.27 nmrad (8 GeV), 1.78 nmrad (7 GeV) and 1.33 nmrad (6 GeV) by utilizing an emittance damping effect by the insertion devices. The designed optics has experimentally been examined at 6 GeV, and the electron beam parameters have been confirmed by measurements at the diagnostics beamlines. * Y. Shimosaki et al., “New Optics with Emittance Reduction at the SPring-8 Storage Ring”, IPAC13, MOPEA027.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO083
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO091	Fundamental Limits of Velocity Bunching of High-brightness Electron Beams	bunching, emittance, cavity, gun	304
	A. Opanasenko, V.V. Mytrochenko NSC/KIPT, Kharkov, Ukraine V.A. Goryashko, V. Zhaunerchyk Uppsala University, Uppsala, Sweden P.M. Salen FYSIKUM, AlbaNova, Stockholm University, Stockholm, Sweden
	The interest in superradiant THz sources based on the coherent transition, synchrotron or undulator radiation grows continuously and such sources require high-quality electron bunches with low emittance, high charge and sub-picosecond (sub-ps) duration. Since accelerator-based THz sources are usually driven by relatively low energy electron bunches of a few tens of MeV, space-charge makes bunch compression to sub-ps level very challenging. In the present work we investigate the feasibility of ballistic bunching down to sub-ps duration while preserving the transverse phase-space quality. We found that in order to compensate for the nonlinear dependency of the arrival time on the energy as well as bunch deformations induced by space-charge effects, one needs to apply a nonlinear energy chirp. This chirp permits to maximize the bunch compression and can be realized by exciting a cavity with higher harmonics of the fundamental frequency. Issues related to synchronizing the harmonics are discussed and the analytical analysis is complemented by simulations with PARMELA.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO091
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO105	Study of Ultra-low Emittance Design for SPEAR3	dipole, emittance, sextupole, quadrupole	337
	M.-H. Wang, R.O. Hettel, X. Huang, T. Rabedeau, J.A. Safranek, K. Tian SLAC, Menlo Park, California, USA
	Funding: Work supported by the US Department of Energy under contract number: DE-AC02-76SF00515 Since its 2003 construction, the SPEAR3 synchrotron light source at SLAC has continuously improved its performance by raising beam current, top-off injection, small alpha and smaller emittance. This makes SPEAR3 one of the most productive light sources in the world. Now to further enhance the operation of SPEAR3, we are looking into the possibility of converting SPEAR3 to a multi-bend achromat storage ring within its site constraint.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO105
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO109	Beam Loss Studies for the KEK Compact-ERL	scattering, simulation, cavity, beam-losses	349
	O. Tanaka, T. Furuya, K. Harada, N. Nakamura, H. Sakai, M. Shimada, K. Umemori KEK, Ibaraki, Japan E. Cenni Sokendai, Ibaraki, Japan
	Beam losses due to eﬀects of Touschek, residual gas, intra-beam scattering, and field emission were studied for the KEK compact Energy Recovery Linac (cERL), which is now under commissioning. By studying the beam losses of cERL, we can better understand the loss mechanisms, estimate the beam loss rates, and localize potentially dangerous areas of the beamline for the future 3GeV ERL project. The goal is to achieve a safety low-emittance and high-current beams operation which can help contribute to the beam loss study under 3GeV ERL project. We used existing and modiﬁed ELEGANT routine to perform the simulations. We also developed a MATLAB data analysis algorithm to handle the large amount of information that is outputted from the program. The data obtained then compared with the theoretical estimation to judge the computation’s accuracy.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO109
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO114	Particle Tracking Simulations with FLUKA for DESY FLASH and EXFEL	radiation, neutron, simulation, photon	363
	V.G. Khachatryan, V.H. Petrosyan, A. Sargsyan, A.V. Tsakanian CANDLE SRI, Yerevan, Armenia
	The objective of the study is the simulation of the produced secondary radiation properties when the electron beam halo particles hit collimator walls. Using particle tracking simulation code FLUKA the European XFEL electron beam interaction with the titanium collimator and copper absorber of the undulator intersections as well as FLASH beam interaction with the tapered collimator were simulated. Absorbed dose spatial distribution in the material of the collimators was simulated for the total secondary radiation and its important photon and neutron components. Residual dose rate after irritation of the collimator material by the electron beam was calculated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO114
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO115	A Low Energy Electron-Scrapersystem for the S-DALINAC Injector	linac, acceleration, controls, target	366
	L.E. Jürgensen, T. Bahlo, C. Burandt, F. Hug, T. Kürzeder, N. Pietralla, T. Schösser, C. Ungethüm TU Darmstadt, Darmstadt, Germany
	Funding: Work supported by DFG through SFB 634 The S-DALINAC is the superconducting linear accelerator of the Institut für Kernphysik at Technische Universität Darmstadt. It delivers an electron beam with energies up to 130 MeV. In order to improve the energy spread and the energy stability of the beam for further acceleration a new scrapersystem has been developed and installed between the 10 MeV injector and the main linac. The system was designed to ensure an energy spread of dE < 10^-03. After installation several tests have taken place, the results will be presented in this work.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO115
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME013	A Python Poisson Solver for 3D Space Charge Computations in Structures with Arbitrary Shaped Boundaries	simulation, rfq, space-charge, ion	406
	G. Pöplau, C. Potratz COMPAEC e.G., Rostock, Germany
	Numerical techniques in the field of particle accelerators are mainly driven by the design of next-generation accelerators: The need for higher simulation complexity and the necessity for more and more specialized algorithms arises from the ever increasing need to include a broader range of physical effects and geometrical details in a computer simulation. This, on the other hand requires fast and reliable simulation tools for a limited user base. Therefore, new approaches in simulation software development are necessary to provide useful tools that are well-suited for the task at hand and that can be easily maintained and adapted by a small user community. We show how Python can be used to solve numerical problems arising from particle accelerator design efficiently. As model problem, the computation of space charge effects of a bunch in RFQs including the vane geometry was chosen and a suited solver was implemented in Python.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME013
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME019	Study of a Fast Convolution Method for Solving the Space Charge Fields of Charged Particle Bunches	simulation, space-charge, ion, electromagnetic-fields	418
	D. Zheng, A. Markoviḱ, G. Pöplau, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
	The kernel of beam dynamics simulations using the particle-in-cell (PIC) model is the solution of Poisson's equation for the electric potential. A very common way to solve Poisson's equation is to use the convolution of charge density and Green's function, the so-called Green's function method. Additionally, the integrated Green's function method* is being used in order to achieve a higher accuracy. For both methods, the convolutions are done using fast Fourier transform based on the convolution theorem. However, the construction of the integrated Green's function and the further convolution is still very time-consuming. The computation can be accelerated without loosing precision if the calculation of Green’s function values is limited to that part of the computational domain with non-zero grid charge density. In this paper we present a general numerical study of these Green's function methods for computing the potential of different bunches: The results can also be used in other simulation codes to improve efficiency. * J. Qiang, S. Lidia, R. D. Ryne, and C. Limborg-Deprey, “A Three-Dimensional Quasi-Static Model for High Brightness Beam Dynamics simulation,” Phys. Rev. ST Accel. Beams, vol 9, 044204 (2006).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME023	A High Precision Particle-moving Algorithm for Particle-in-cell Simulation of Plasma	simulation, cyclotron, plasma, experiment	427
	X.F. Li, D.Z. Chen, D. Li, H.K. Yue HUST, Wuhan, People's Republic of China
	A new particle-moving algorithm for particle-in-cell simulation of plasma is developed based on the Linear Multistep Method. The conventional and the new algorithms are investigated by numerical experiments, which are conducted in three typical fashions of the electron motions in electromagnetic fields, that is, cyclotron in homogeneous magnetic field, drift in field and motions in inhomogeneous magnetic field. The new algorithm not only improves the accuracy but also relaxes the time step condition for the simulation. It can increase the computation efficiency.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME023
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME025	New Possibilities of MultP-M Code	simulation, multipactoring, RF-structure, operation	433
	M. Gusarova, S. Khudyakov, I.I. Petrushina, Ya.V. Shashkov MEPhI, Moscow, Russia
	Implementation and Testing of the new module package for geometry import of the MultP-M 3D code for multipacting prediction was performed. The results of simulations for the coaxial line specimen using this new module are presented. These results are compared with analytical calculations and experimental data.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME025
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME026	IBS Simulations with Compute Unified Device Architecture (CUDA) Technology	scattering, simulation, GPU, factory	436
	S.A. Glukhov, E.B. Levichev, S.A. Nikitin, P.A. Piminov, D.N. Shatilov, S.V. Sinyatkin BINP SB RAS, Novosibirsk, Russia
	A program code for 6D tracking has been developed taking into account IBS (Intra-Beam Scattering) and Touschek effect and using Monte-Carlo method. The simulation algorithm has been developed on the basis of well-known IBS theory presented in (). The resulting program can be executed using GPGPU devices (General-Purpose Graphics Processing Units) supporting CUDA technology (Compute Unified Device Architecture). J. Le Duff, Single and multiple Touschek effects // Published in In Rhodos 1993, Advanced accelerator physics, vol. 2 573-586. CERN Geneva - CERN-95-06 (95/11,rec. Mar.96) 1993. p. 573-586.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME026
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME029	Simulation of Low Energy Charged Particle Beams	simulation, cyclotron, extraction, quadrupole	442
	O. Karamyshev, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom O. Karamyshev, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom
	Low energy particle beams pose specific challenges to simulation codes and experiments alike as a number of effects become important that can often be neglected at higher beam energies, including e.g. space-charge or fringe field effects. The optimization of low energy charged particle beam transport through arbitrary electromagnetic fields is the purpose of a code aimed at tracking low-energy particles from the sub-eV to the MeV energy range with high precision. The code is based on Matlab/Simulink and able to use 3-dimensional field maps from either Finite Elements Method (FEM) solvers, such as Comsol, OPERA 3D or CST particle studio, fields calculated by the code itself, or field maps from measurements. This contribution describes the code structure and presents its performance limitations. It also gives a summary of results obtained from beam dynamics simulations of cyclotrons injection systems, storage ring extraction systems, electrostatic and magnetic beamlines, as well as from photocathode optimization studies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME029
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME033	Beam Dynamics in an Electron Lens with the Warp Particle-in-cell Code	simulation, collider, gun, solenoid	451
	G. Stancari Fermilab, Batavia, Illinois, USA V. Moens EPFL, Lausanne, Switzerland S. Redaelli CERN, Geneva, Switzerland
	Funding: Fermi Research Alliance, LLC operates Fermilab under Contract DE-AC02-07CH11359 with the US Department of Energy. Research supported in part by US LARP and EU FP7 HiLumi LHC, Grant Agreement 284404. Electron lenses are a mature technique for beam manipulation in colliders and storage rings. In an electron lens, a pulsed, magnetically confined electron beam with a given current-density profile interacts with the circulating beam to obtain the desired effect. Electron lenses were used in the Fermilab Tevatron collider for beam-beam compensation, for abort-gap clearing, and for halo scraping. They will be used in RHIC at BNL for head-on beam-beam compensation, and their application to the Large Hadron Collider for halo control is under development. At Fermilab, electron lenses will be implemented as lattice elements for nonlinear integrable optics. The design of electron lenses requires tools to calculate the kicks and wakefields experienced by the circulating beam. We use the Warp particle-in-cell code to study generation, transport, and evolution of the electron beam. For the first time, a fully 3-dimensional code is used for this purpose.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME033
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME043	Modeling and Simulation of Beam-induced Plasma in Muon Cooling Devices	plasma, simulation, cavity, ion	466
	K. Yu SBU, Stony Brook, USA M. Chung, A.V. Tollestrup, K. Yonehara Fermilab, Batavia, Illinois, USA B.T. Freemire IIT, Chicago, Illinois, USA V. Samulyak BNL, Upton, Long Island, New York, USA V. Samulyak SUNY SB, Stony Brook, New York, USA
	Understanding of the interaction of muon beams with plasma in muon cooling devices is important for the optimization of the muon cooling process. We have developed numerical algorithms and parallel software for self-consistent simulation of the plasma production and its interaction with particle beams and external fields. Simulations support the experimental program on the hydrogen gas filled RF cavities in the Mucool Test Area (MTA) at Fermilab. Computational algorithms are based on the electromagnetic particle-in-cell (PIC) code SPACE combined with a probabilistic, macroparticle-based implementation of atomic physics processes such as the absorption of the incident particles, ionization of the absorber material, and the generation and evolution of secondary particles in dense, neutral gas. In particular, we have proposed a novel algorithm for dealing with repetitive incident beam, enabling simulations of long time scale processes. Benchmarks and simulations of the experiments on gas-filled RF cavities and prediction for future experiments are discussed. * kwangmin.yu@stonybrook.edu ** rosamu@bnl.gov
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME043
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME044	Upgrade of the Machine Interlock System for the ELBE Accelerator Facility	PLC, vacuum, controls, status	469
	M. Justus, M. Freitag, B. Lange, P. Michel, W. Sorge, R. Steinbrück, H. Tietze HZDR, Dresden, Germany
	The ELBE facility with its 40 MeV C.W. LINAC has recently received an upgrade in terms of new secondary radiation sources and beam lines, while advancing the accelerator infrastructure towards 1.6 mA C.W. operation (1.0 mA before). Therefore, the machine interlock system (MIS) was redesigned in parts to meet the new timing requirements resulting from the increased overall beam power. It comprises fast beam loss detection and a PLC based beam line equipment protection system (EPS), both tripping the key components of the electron sources. The former tripping system using PLC interrupts was replaced by an in-house developed staggered CPLD based system with optical transmission and a PROFINET IO interface for control system integration. The EPS is distributed on several PLCs and has been improved in terms of M2M communication. Further, the vacuum inrush protection was completely renewed using brought-in equipment. This contribution depicts the technical features and performance of the MIS subsystems, as well as the actual status within the upgrade project.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME044
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME051	Turbo Generators for Powering the HV-solenoids at the HESR Electron Cooler	solenoid, high-voltage, power-supply, acceleration	492
	A. Hofmann, K. Aulenbacher, M.W. Bruker, J. Dietrich, T. Weilbach HIM, Mainz, Germany M.I. Bryzgunov, A.P. Denisov, V.M. Panasyuk, V.V. Parkhomchuk, V.B. Reva BINP SB RAS, Novosibirsk, Russia
	New experiments at the planned 'High Energy Storage Ring' (HESR) require magnetised electron cooling. One of the challenges is the powering of the HV-solenoids, because they are located on HV-sections, which sit on an electrical potential inside a high voltage vessel. We discuss a Multi-MV system where the solenoids are powered by a series of cascade transformers which are in turn supplied by turbogenerators. The usage of SF6 as turbine fluid is desirable from the viewpoint of operational stability and may also lead to energy efficient operation of the turboexpanders since a Organic Rankine-cycle (so-called ORC-process) may be used instead of electrically driven compressors. The paper gives an overview of the turbo generator and ORC project: an introduction, a status report and a road map will be given.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME051
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME067	Kicker Development at the ELBE Facility	kicker, positron, gun, SRF	520
	G.S. Staats FZD, Dresden, Germany A. Arnold, H. Büttig, T. Kirschke, M. Kuntzsch, P. Michel, J. Teichert, H. Vennekate, A. Wagner, R. Xiang HZDR, Dresden, Germany R. Krause-Rehberg, A. Müller Martin-Luther-Universität, Naturwissenschaftliche Fakultät II, Halle (Saale), Germany
	Kicker-devices, also known as choppers, are of great interest for a multi-purpose electron accelerator like the ELBE at HZDR. They serve the following three main tasks: Firstly, they can be used to improve the time resolution for the positron beam line by removing certain parts of the bunch. As a second advantage they enable the machine to run two independent experiments at the same, as a chopper may split the beam into two separate parts. Lastly, a well-positioned kicker can reduce the dark current emitted by the SRF injector of the accelerator. Different designs for structures, deflecting the bunch in the beam line, have been simulated using CST Particle Studio. Here, no big difference to well-known strip line structures do exist. The next step is to design the supply electronics driving the kickers. As the ELBE accelerator runs at a high bunch repetition rate, the kicker has to keep up to this frequencies of up to 13 MHz. Hence, the high power levels needed for the operation may cause additional problems for the driver electronics. The poster is going to present the state of our development for all three tasks and our approaches to solve the corresponding challenges.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME067
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME073	Status of Injection Complex VEPP-5: Machine Commissioning and First Experience of Positron Storage	injection, positron, dumping, damping	538
	A.A. Starostenko, F.A. Emanov, E.S. Kazantseva, P.V. Logatchov BINP SB RAS, Novosibirsk, Russia
	The Injection complex VEPP-5 consist of S-band linear accelerators (270 and 420 MeV), positron convertor (at 270 MeV) and damping ring. The injection complex is in commission. Positron rate production about 6·10⁸ positrons/pulse and conversion yield 0.14/GeV was achieved. Storage ring positron beam current is 70mA was achieved.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME073
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI002	Design, Manufacture and Operation of the Beam Spoiler for Positron Target Protection	target, positron, alignment, linac	573
	L. Zang, K. Kakihara, T. Kamitani, K. Mikawa, F. Miyahara, T. Suwada KEK, Ibaraki, Japan
	In order to produce positrons, intensive pulsed electron beam is used to strike on a tungsten target. The energy deposition is distributed non-uniformly over the target, leading to a mechanical stress. As a result of large thermal gradient, the target could be potentially damaged. To avoid the target destruction, the peak energy deposition density (PEDD) in the target should be well below the critical limit (35J/g) based on the SLAC operational experience. With an expected primary electron spot size on the target of the SuperKEKB positron source, the PEDD will exceeds the limit. We will introduce a beam spoiler to enlarge the spot size by multiple scattering in thin beam screen and aluminum plate. It reduces the PEDD down to half of the limit. This paper describes the design of the spoiler and the beam screen system used in the positron beam commissioning of the SuperKEKB positron source started in 2014.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI002
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI003	Positron Yield Optimization by Adjusting the Components Offset and Orientation	positron, target, injection, simulation	576
	L. Zang, M. Akemoto, S. Fukuda, K. Furukawa, T. Higo, N. Iida, K. Kakihara, T. Kamitani, T. Miura, F. Miyahara, Y. Ogawa, H. Someya, T. Takatomi, K. Yokoyama KEK, Ibaraki, Japan S. Ushimoto Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
	In order to keep high luminosity beam collision condition at SuperKEKB, low emittance electron/positron injection and flexible pulse-to-pulse switching of these beam modes are essential requirements. While a primary electron beam strikes on a target to generate positrons, an injection electron beam passes through a small hole besides the target. Since the injection electron orbit should be on axis to avoid emittance growth, the target and the flux concentrator for positron focusing have a few millimeters offset from the axis. This offset positron generation gives significant degradation in the positron yield. In this paper, we will discuss positron yield improvement by proper orientation of the cut-in slit of the flux concentrator which yields un-symmetric field distribution and primary electron incident point. With particle tracking simulation taking three dimensional field distribution into account, an ideal positron trajectory giving optimum yield was found.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI003
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI004	SuperKEKB Positron Source Construction Status	positron, target, solenoid, operation	579
	T. Kamitani, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, Y. Funakoshi, K. Furukawa, T. Higo, H. Honma, N. Iida, M. Ikeda, E. Kadokura, H. Kaji, K. Kakihara, H. Katagiri, M. Kikuchi, H. Koiso, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Mimashi, T. Miura, F. Miyahara, T. Mori, A. Morita, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, Y. Ohnishi, S. Ohsawa, M. Sato, T. Shidara, A. Shirakawa, M. Suetake, H. Sugimoto, T. Suwada, T. Takatomi, T. Takenaka, M. Tanaka, M. Tawada, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou KEK, Ibaraki, Japan D. Satoh TIT, Tokyo, Japan
	The KEKB positron source is under the upgrade for SuperKEKB. The previous positron production target and capture section have been removed and the new system is constructed at a location forty meters upstream to have sufficient energy margin for beam injection to the newly introduced damping ring. A flux concentrator is introduced in the new capture section to make an adiabatic matching system. Large aperture (30mm in diameter) S-band accelerating structures are introduced in the capture section and in the subsequent accelerator module to enlarge the transverse phase space acceptance. The beam focusing system of quadrupoles is also upgraded for a comparable beam acceptance to that of the capture section. This paper reports on the status of the SuperKEKB positron source construction and the preliminary positron beam commissioning.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI004
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI005	The AWAKE Experimental Facility at CERN	proton, plasma, laser, experiment	582
	E. Gschwendtner, T. Bohl, C. Bracco, A.C. Butterworth, S. Cipiccia, S. Döbert, V. Fedosseev, E. Feldbaumer, C. Heßler, W. Höfle, M. Martyanov, M. Meddahi, J.A. Osborne, A. Pardons, A.V. Petrenko, H. Vincke CERN, Geneva, Switzerland
	AWAKE, an Advanced Wakefield Experiment is launched at CERN to verify the proton driven plasma wakefield acceleration concept. Proton bunches at 400 GeV/c will be extracted from the CERN SPS and sent along a 750m long proton line to the plasma cell, a Rubidium vapour source, where the proton beam drives wakefields reaching accelerating gradients at the order of gigavolt per meter. A high power laser pulse will co-propagate within the proton bunch creating the plasma by ionizing the (initially) neutral gas. An electron beam will be injected into the plasma cell to probe the accelerating wakefield. The AWAKE experiment will be installed in the CNGS facility. First proton beam to the plasma cell is expected by end 2016. The design of the experimental area and the integration of the new beam-lines as well as the experimental equipment will be shown. The needed modifications of the infrastructure in the facility will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI005
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI006	Possible Uses of Gamma-rays at Future Intense Positron Sources	undulator, positron, synchrotron, software	586
	A.O. Alrashdi, I.R. Bailey Lancaster University, Lancaster, United Kingdom A.O. Alrashdi, I.R. Bailey, D. Newton Cockcroft Institute, Warrington, Cheshire, United Kingdom A.O. Alrashdi KACST, Riyadh, Kingdom of Saudi Arabia D. Newton The University of Liverpool, Liverpool, United Kingdom
	Funding: This research is funded in part by STFC grant ST/G008248/1 The baseline design of the ILC (International Linear Collider) positron source requires the production of an intense flux of gamma rays. In this paper we present an investigation of using the gamma ray beam of the ILC for additional applications, including nuclear physics. As a result of changing the collimator shape, as well as the parameters of the undulator magnets, we obtained spectra from numerical simulations using the HUSR/GSR software package. We present results from simulations and a discussion of possible future investigations in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI006
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI011	Control of Plasma Flux with Pulsed Solenoid for Laser Ion Source	ion, plasma, ion-source, laser	601
	S. Ikeda, K. Horioka TIT, Yokohama, Japan Y. Fuwa, S. Ikeda, M. Kumaki RIKEN, Saitama, Japan T. Kanesue, M. Okamura BNL, Upton, Long Island, New York, USA
	We discuss the behavior of laser-ablation plasma spreading through a pulsed solenoidal field to minimize the beam emittance of laser-ablation ion source (LIS). LIS is expected to produce high-flux and low emittance ion beams from various solid materials in vacuum because of the high drift velocity and low temperature of the ablation plasma due to the adiabatic expansion. However, the ion flux level from the ablation plasma into an extraction gap changes within a pulse and then the shape of the sheath boundary changes transiently. Then, the integrated emittance is larger than the stroboscopic emittance at a certain time slice. To prevent the transient effect, we tried to control the plasma flux with a pulsed solenoidal magnetic field. The field is expected to change the direction of the plasma flow like a lens. By changing the magnetic flux density according to the transient flux level of ablation plasma, we can expect to control the plasma flux at the extraction gap. To investigate the controllability of the plasma flow, we measured the plasma flux as a function of parameters of the pulsed magnetic field. We scanned ion probes along the beam.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI011
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI017	Status of AREAL RF Photogun Test Facility	gun, laser, operation, emittance	620
	B. Grigoryan, G.A. Amatuni, V.S. Avagyan, H. Avdishyan, H. Davtyan, A.A. Gevorgyan, L.H. Hakobyan, M. Ivanyan, V.G. Khachatryan, E.M. Laziev, A. Lorsabyan, M. Manukyan, I.N. Margaryan, N. Martirosyan, T.H. Mkrtchyan, S. Naghdalyan, V.H. Petrosyan, H. Poladyan, V. Sahakyan, A. Sargsyan, A.V. Tsakanian, V.M. Tsakanov, A. Vardanyan, V. V. Vardanyan, G.S. Zanyan CANDLE SRI, Yerevan, Armenia T.K. Sargsyan LT-PYRKAL cjsc, Yerevan, Armenia
	Advanced Research Electron Accelerator Laboratory (AREAL) is a 20 MeV laser driven RF linear accelerator which is being constructed in the CANDLE institute. The construction of phase-1 is finished and at present the machine commissioning is in progress. In phase-1 a photocathode RF gun provides a 5 MeV small emittance electron beam with the 100 pC bunch charge and variable electron bunch length from 0.5 to 8 ps. Two main operation modes are foreseen for this phase – single and multibunch regimes to satisfy experimental demands. We report the status of linac, first experience and nearest machine run schedule. The brief review of the facility, main parameters, performance and first results are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI017
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI019	In-situ Characterization of K2CsSb Photocathodes	cathode, laser, vacuum, ion	627
	M. Schmeißer, A. Jankowiak, T. Kamps, S.G. Schubert HZB, Berlin, Germany S.G. Schubert BNL, Upton, Long Island, New York, USA
	Funding: Work supported by German Bundesministerium für Bildung und Forschung contract 05K12CB2 PCHB and Land Berlin. Alkali antimonide photocathodes with high quantum efficiency hold the promise of delivering electrons for high-brightness injectors. A drift type spectrometer (momentatron) was attached to the HZB preparation system to allow in-situ characterization within short time after fabrication and possibly identify correlations between growth process and cathode performance parameters.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI020	Introducing GunLab – A Compact Test Facility for SRF Photoinjectors	gun, SRF, laser, cathode	630
	J. Völker, R. Barday, A. Jankowiak, T. Kamps, J. Rudolph, S.G. Schubert, S. Wesch HZB, Berlin, Germany A. Ferrarotto, T. Weis DELTA, Dortmund, Germany V.I. Shvedunov MSU, Moscow, Russia I.Yu. Vladimirov MSU SINP, Moscow, Russia
	Funding: Work supported by German Bundesministerium für Bildung und Forschung (BMBF contract 05K12CB2 PCHB and 05K10PEA), Land Berlin and grants of Helmholtz Association Superconducting radio-frequency photoelectron injectors (SRF photoinjectors) are a promising electron source for high brightness accelerators with high average current and short pulse duration like FELs and ERLs. For the upcoming ERL project BERLinPro we want to test and commission different SRF photoinjectors and examine the beam performance of photocathode materials in an independent test facility. Therefore we designed GunLab to characterize the beam parameters from the SRF photoinjectors in a compact diagnostics beamline. In GunLab we want to investigate the complete 6 dimensional phase space as a function of drive laser and RF setup parameters. In this work we present the design and the estimated performance of GunLab.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI020
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI021	Laser Systems Generating Short Polarized Electron Bunches at the S-DALINAC	laser, operation, experiment, cathode	633
	M. Espig, J. Enders, Y. Fritzsche, A. Kaiser, M. Wagner TU Darmstadt, Darmstadt, Germany
	Funding: Supported by DFG within CRC634 and by the state of Hesse through the LOEWE center HIC for FAIR. The source of polarized electrons at the superconducting Darmstadt electron linear accelerator S-DALINAC uses photo-emission from strained-layer superlattice-GaAs and bulk-GaAs photocathodes. This system is driven by either 3 GHz gain-switched diode lasers or a short-pulse Ti:Sapphire laser system. Highly polarized electrons are generated with laser light at 780 nm, while blue laser light is used for unpolarized high-current experiments. We present the existing pulsed laser systems and the planned developments for the diode laser system, including, e.g., impedance matching of the diode lasers, gain switching with short electrical pulses and pulsing with a Mach-Zehnder modulator. The pulsed operation is aimed at generating short electron bunches (< 50 ps) at the S-DALINAC with variable repetition rates from some MHz to 3 GHz.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI026	Complete Simulation of Laser Induced Field Emission from Nanostructures Using a DGTD, PIC and FEM Code	laser, simulation, cathode, space-charge	645
	A. Fallahi, F.X. Kärtner CFEL, Hamburg, Germany K.K. Berggren, R. Hobbs, F.X. Kärtner, P.D. Keathley, M.E. Swanwick, L.F. Velasquez-Garcia, Y. Yang MIT, Cambridge, Massachusetts, USA
	Funding: DARPA contract number N66001-11-1-4192 and the Center for Free-Electron Laser Science, DESY Hamburg. We present a general and efficient numerical algorithm for studying laser induced field emission from nanostructures. The method combines the Discontinuous Galerkin Time Domain (DGTD) method for solving the optical field profile, the Particle-In-Cell (PIC) method for capturing the electron dynamics and the Finite Element Method (FEM) for solving the static field distribution. The charge distribution is introduced to the time-domain method based on a modified Fowler-Nordheim field emission model, which accounts for the band-bending of the charge carriers at the emitter surface. This algorithm is capable of considering various effects in the emission process such as space-charge, Coulomb blockade and image charge. Simulation results are compared with experimental findings for optically driven electron emission from nanosharp Si-tips.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI026
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI027	Dark Current Studies at Relativistic Electron Gun for Atomic Exploration – REGAE	gun, cavity, vacuum, operation	649
	H. Delsim-Hashemi, K. Flöttmann DESY, Hamburg, Germany
	Electron diffraction is a tool for exploring structural dynamics of matter. The scattering cross section is orders of magnitude higher for electrons than for X-rays so that only a small number of electrons is required to achieve comparable results. However, the required electron beam quality is extraordinary. To study e. g. proteins a coherence length of 30 nm is required which translates into a transverse emittance of 5 nm at a spot size of 0.4mm. In addition short bunch lengths down to 10 fs and a temporal stability of the same order are required in order to study chemical reactions or phase transitions in pump probe type experiments. These are challenging parameters for an electron source, which demand improvements at many frontiers. Dark current degrades contrast of diffraction patterns in all experiments. Understanding dark-current generation and propagation can lead to better methods to decrease it. In this paper dark current studies that are performed at REGAE will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI027
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI028	Different Countermeasures of Electron Amplification in the Photocathode Unit	cathode, SRF, gun, simulation	652
	E.T. Tulu, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany A. Arnold HZDR, Dresden, Germany
	Funding: Federal Ministry for Research and Education BMBF; Project: 05K2013-HOPE Superconducting radio frequency (SRF) structures may be subjected to electron multipacting (MP). The electrons emitted from one of the structure’s wall under certain conditions are accelerated by the RF field, thereby they may impact the wall again based on the field pattern in the structure. Accordingly the number of electrons increases exponentially caused by secondary electron emission. The latter depends on the secondary emission coefficient of the surface material and the electron trajectory in the device under study. This phenomenon limits the accelerating gradient in the cavity, moreover, it might cause an impair of RF components and distortion of the RF signal. Therefore, there should be an efficient countermeasure to suppress MP in order to boost the performance of the SRF gun. In this paper, three techniques of suppression of MP from the vicinity of the cathode, such as DC-bias, geometric modification and the microstructure of the cathode's surface, in the Rossendorf SRF gun are presented. The simulation has been done using CST Microwave Studio® and CST Particle Studio®*. Eventually, the efficient suppression method would be chosen for this particular case. H.Padamsee, J. Knobloch and T. Hays, 1998, Ch. 10. E. T. Tulu, A. Arnold and U. van Rienen, 16th International Conference on SRF, Paris, France, 2013. * CST AG, http://www.cst.com.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI028
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI029	Spectrometer for Laser-pulsed Electrons from Field Emission Cathodes	cathode, laser, detector, controls	655
	S. Mingels, B. Bornmann, D. Lützenkirchen-Hecht, G. Müller, V. Porshyn Bergische Universität Wuppertal, Wuppertal, Germany
	Funding: German Federal Ministry of Education and Research (BMBF). Project number: 05K13PX2. In order to develop highly brilliant, pulsed electron sources based on photo-induced field emission (PFE), which combines advantages of photo and field emission (FE), a new measurement system was constructed at BUW. In an UHV system the electrons are extracted from a cold cathode by a mesh electrode under pulsed laser illumination (3.5 ns, 10 Hz, 0.5 – 5.9 eV, > 0.3 mJ) and so far analyzed by a CW-spectrometer. Quantum efficiency investigations of flat metal (Au, Ag of different surface orientations) and semiconductor crystals (n- and p-Si, GaN) yielded the expected work functions and revealed first hints for PFE effects. However, the kinetic energy of the electrons could not be measured with the CW-spectrometer. In addition, the achievable electric field (< 20 MV/m) was limited by parasitic FE. Hence, the system is presently upgraded with a spectrometer (resolution < 3 meV) that can handle electron pulses and a dust reduced environment is installed at the load lock. First results acquired with the upgraded apparatus on PFE cathodes will be presented at the conference. B. Bornmann et al., Rev. Sci. Instrum. 83, 013302 (2012). ** S. Mingels et al., Proc. FEL2013, New York, USA, p. 339.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI029
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI030	Basic Design of a 20K C-band 2.6-cell Photocathode RF Gun	cavity, gun, simulation, vacuum	658
	T. Tanaka, M. Inagaki, K. Nakao, K. Nogami, T. Sakai LEBRA, Funabashi, Japan M.K. Fukuda, T. Takatomi, J. Urakawa, M. Yoshida KEK, Ibaraki, Japan T.S. Shintomi Nihon University, Tokyo, Japan
	Funding: This research was supported by the Photon and Quantum Basic Research Coordinated Development Program of the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT). A cryocooled C-band photocathode RF gun operating at 20K is under design at Nihon University. The RF gun is of BNL-type 2.6-cell pillbox cavity with a resonant frequency of 5712 MHz. With high-purity Oxygen-free copper used as the cavity material, the quality factor of the cavity is expected to be approximately 60000 from theoretical prediction of the anomalous skin effect at low temperatures. Considering the cooling capacity, initial operation of the RF gun is assumed at a duty factor of 0.01%. The cavity elements designed for low-power test is in preparation for machining. The low-power test at room temperature is scheduled early spring in 2014 before assembled at KEK by means of diffusion bonding technique. Since it is intended for the basic understanding and measurements of low temperature RF properties, the cavity is not equipped with structures for the photocathode assembling or the RF input coupler. The cavity design and the results of RF properties measured at room temperature before diffusion bonding will be reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI030
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI031	Multi-alkali Photocathode R&D	cathode, laser, vacuum, experiment	661
	Y. Seimiya, M. Kuriki, N. Yamamoto HU/AdSM, Higashi-Hiroshima, Japan
	Multi-alkali photocathode has excellent features: high quantum efficiency, long lifetime, and excitation by visible light, for example green laser. The multi-alkali cathode is considered to be one of the best candidate of the high brightness electron source of the advanced electron accelerator such as ERL and FEL. We study conditions of multi-alkali evaporations, such as thicknesses, substrate temperature, and evaporation rate, and examine the cathode performances, such as quantum efficiency and extractable current density. Antimony (Sb), potassium (K), and cesium (Cs) are used in our evaporation system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI031
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI032	A STUDY ON ROBUSTNESS OF NEA-GAAS PHOTOCATHODE*	cathode, vacuum, experiment, emittance	664
	K. Uchida, R. Kaku, M. Kuriki, K. Miyoshi, Y. Seimiya, N. Yamamoto HU/AdSM, Higashi-Hiroshima, Japan H. Iijima Tokyo University of Science, Tokyo, Japan
	Electron source is one of the most important component in the advanced linac. There is a strong demand on the high performance cathode, such as small emittance, high brightness, and short pulse generation. NEA-GaAs photo-cathode is a unique technology which is capable for generating highly polarized and extremely low emittance beam. Quantum efficiency (QE) of the cathode is high in near IR region, so it is favor to generate a high current density beam. These advantages are originated to the Negative Electron Affinity (NEA) surface, but it is fragile so the operational lifetime is limited. A study on a robust NEA surface cathode is reported. According to the hetero-junction model, Cs-Te thin film deposited on GaAs forms a robust NEA surface. We performed the Cs-Te evaporation experiment on a clean GaAs cathode and measured QE spectra. We found that some sample showed a high quantum efficiency up to 900nm wavelength which strongly suggested a NEA surface formation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI032
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI034	Development of temporal response measurement system for transmission-type spin-polarized photocathodes	cavity, laser, resonance, linear-collider	670
	T. Inagaki, M. Hosaka, Y. Takashima, N. Yamamoto Nagoya University, Nagoya, Japan M. Adachi KEK, Ibaraki, Japan X.G. Jin Institute for Advanced Research, Nagoya, Japan M. Katoh, T. Konomi UVSOR, Okazaki, Japan Y. Okano IMS, Okazaki, Japan
	Spin polarized electron beam is essential for "International Linear Collider". In Nagoya University, transmission-type spin-polarized photocathodes have been developed, and the quantum efficiency of 0.5 % and the polarization of 90 % were achieved,. Recently, we succeeded in making the active layer several times thicker with keeping the spin polarization on the GaAs/GaAsP strain-compensated superlattice photocathode*. Increasing the thickness of the active layer is very advantageous for high quantum efficiency, but might be disadvantageous for pulse response. In order to investigate the pulse response, we have developed a pulse length measurement system by using an RF deflecting cavity. In the measurement, magnetic field induced on the beam axis kicks electron pulse transversely and the pulse length is projected to the transverse plane, which is measured by knife-edge method. The pump laser pulses are provided by a Ti:sapphire laser oscillator. By using a pulse stretcher, the pulse width of the pump laser can be changed in the range between 130 fs and 20 ps. In the poster session, we will describe the details of the measurement system and the most recent experimental results. T. Nakanishi, The XXI International LINAC Conference(1998) Xiuguang Jin, Japanese Journal of Applied Physics 51 (2012) 108004 * Xiuguang Jin, Applied Physics Express 6 (2013) 015801
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI034
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI035	Development of the Photocathode LiTi2O4 and Evaluations of the Initial Emittance	cathode, laser, emittance, cavity	673
	R. Inagaki, M. Hosaka, Y. Takashima, N. Yamamoto Nagoya University, Nagoya, Japan T. Hitosugi, S. Shiraki Tohoku Uneversity, WPI-AIMR, Sendai, Japan E. Kako, Y. Kobayashi, S. Yamaguchi KEK, Ibaraki, Japan M. Katoh, T. Konomi, T. Tokushi UVSOR, Okazaki, Japan Y. Okano IMS, Okazaki, Japan
	In UVSOR, the X-ray free electron laser (XFEL) based on linear accelerator with high pulse repetition about 1MHz has been designed as a candidate for the next radiation sources. We thought a combination of superconducting RF cavity and photocathode is an optimal electron gun for the new accelerator. For this electron gun, we propose a back-illuminated multi-alkali* photocathode with transparent superconductor LiTi2O4*. The reason for using LiTi2O4 is to reflect RF by using feature of penetration depth of superconductor, which is defined from London equation. This feature protects optical components from RF damage. However, LiTi2O4 is a new material and properties are not clear. We have measured the basic properties of this photocathode, such as magnetic susceptibility measurement and photoelectron spectrometry, etc. In this conference, we will explain the detail of the concept and advantage of this cathode, and show the result measured about the basic properties of this photocathode focusing on the initial emittance measurement. A. V. Lyashenko et al. JINST 4 P07005 (2009) ** Kumatani et al. APL 101 (2012) 123103″
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI035
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI036	Pulse Radiolysis Using Terahertz Probe Pulses	laser, radiation, gun, linac	676
	K. Kan, M. Gohdo, T. Kondoh, K. Norizawa, I. Nozawa, A. Ogata, T. Toigawa, J. Yang, Y. Yoshida ISIR, Osaka, Japan
	Pulse radiolysis, which utilizes a pump electron beam and a probe pulse, is a powerful tool that can be used for the time-resolved observation of ultrafast radiation-induced phenomena. Recently, double-decker pulse radiolysis* using visible probe pulses were demonstrated based on a photocathode RF gun driven by two UV pulses, which enabled synchronized pump electron beam and visible probe pulses. In this study, pulse radiolysis using terahertz (THz) probe pulses which were realized by the “double-decker” electron beams and dynamics of transient quasi-free electrons in semiconductors are presented. * K. Kan et al., Rev. Sci. Instrum. 83, 073302 (2012).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI036
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI037	Development of Iridium Cerium Photocathode for the Generation of High-Charge Electron Beam	laser, cathode, gun, linac	679
	D. Satoh TIT, Tokyo, Japan N. Hayashizaki RLNR, Tokyo, Japan T. Natsui, M. Yoshida KEK, Ibaraki, Japan
	We developed an iridium cerium cathode material made by new production method for multi-purpose electron source. For multi-purpose electron source, we focused on the Ir5Ce compound which has a high melting point (> 2100 K) and a low work function (2.57 eV). This material has some excellent properties as both a thermionic cathode and a photocathode. For example, Ir5Ce thermionic cathode can generate one-order higher electrical current than a LaB6 cathode at the same temperature. Another advantage is that an Ir5Ce thermionic cathode has a lifetime two orders longer than that of a LaB6 thermionic cathode under the same conditions. Moreover, we discovered that this material has a reasonably high quantum efficiency (2.70 × 10−3 @213nm at 1000°C) and long-lifetime (> LaB6) as a photocathode. Our research shows that Ir5Ce compound is optimum material for a thermionic cathode and photocathode. We focused on this good emission properties under the high temperature and we tried to develop a backside electron beam heating system and demonstrate a laser pre-pulse heating for a high current thermionic gun system or high charge photocathode gun.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI037
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI038	Study on Quantum Efficiency of NEA-GaAs with Various Thermal Treatments; The Increase in Quantum Efficiency by the Low Temperature Treatment.	ion, site, experiment, vacuum	682
	K. Hayase, R. Chiba, H. Iijima, Y. Inagaki, T. Meguro Tokyo University of Science, Tokyo, Japan
	Negative electron affinity (NEA) surface are formed by deposition of Cs atoms on p-GaAs, and the drastic increase in the electron emission is observed by the Yo-Yo method. It is necessary to remove oxide layers of GaAs surface for the NEA surface formation, therefore the thermal treatment was carried out prior to the NEA activation. We have discussed the quantum efficiency (QE) with different thermal history. GaAs surfaces cleaned with organic solvents were thermally treated with the temperature sequence of 773K, 823K, and 723K. The NEA activation was carried out at every temperature. The QE less than 1% was obtained with 773K of treatment temperature on the initial surface. Then the QE increased at 10% after treatment at higher 823K. Successive increase of the QE to 13% was observed with a reduced temperature treatment at 723K. The GaAs surfaces after the thermal treatment in the high temperature region with the NEA activation are different from the as-cleaned-GaAs surfaces probably in stoichiometry or morphology due to desorption of As and Ga atoms. The role of thermal treatment with NEA activation is the modification of surface properties important for elevating the QE.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI038
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI039	Ultra-short Electron Bunch Generation using Energy-chirping Cell Attached RF Electron Gun	gun, cavity, simulation, radiation	685
	K. Sakaue, Y. Koshiba, M. Mizugaki, M. Washio Waseda University, Tokyo, Japan R. Kuroda AIST, Tsukuba, Ibaraki, Japan T. Takatomi, J. Urakawa KEK, Ibaraki, Japan
	Funding: Work supported by JSPS Grant-in-Aid for Young Scientists (B) 23740203 and Scientific Research (A) 10001690 We have been developing an Energy-Chirping-Cell attached RF electron gun (ECC-RF-Gun) for generating ultra-short electron bunches. ECC-RF-Gun has extra cell at the end of gun cavity in order to chirp the bunch energy. Such a bunch can be compressed by the velocity difference though the drift space. We have already installed it to our accelerator system and successfully observed a coherent synchrotron/transition radiation at 0.3THz. It is clear that the bunch length was short enough to generate 0.3THz, which corresponds to less than 500fs bunch length was achieved if we assume the gaussian shape. In this conference, the principle of ECC-RF-Gun, the recent results of bunch length measurement and future prospective will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI039
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI040	Design and Analysis of an Electron Beam in an Electron Gun for X-Ray Radiotherapy	gun, cathode, emittance, simulation	688
	J.C. Lee, J.-S. Chai, M. Ghergherehchi, H.S. Kim, Y.S. Lee, S. Shin, Y.H. Yeon SKKU, Suwon, Republic of Korea B.N. Lee KAERI, Dae-jeon, Republic of Korea
	Funding: This work was supported by (IT R&D program of MSIP/KEIT [10043897] and MOTIE [13-DU-EE-12]) in KOREA. Electron linear accelerators are used as x-ray generators for diagnosing the human body. In this paper conceptual design of electron beam for compact electron gun was calculated by using EGN2w and CST-Particle Studio codes. The structure of the electron gun was used for Pierce and diode type and the specification of electron beam was selected as 500 cGy/min. Specifications of designed electron gun were focused on current, beam size and normalized emittance. Optimized beam current, diameter and normalized emittance are 226.88 mA, 0.689 mm (Full width) and 1.03π mm• mrad, respectively by using two simulation codes. Accuracy of simulation was verified by comparison of emitted beam current which has error of 0.74%. * Subhash C. Sharma et al., Journal of applied clinical medical physics, 8, 3 (2007) 119-125. * Yuichiro Kamino et al., Med. Phys. 34 (2007) 1797-1808.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI040
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI041	Electrons Injectors with Cathode Diameter of 6/15mm and New Cup Energy Input on the Wave E11 for Accelerators	cathode, Windows, gun, target	692
	K.G. Simonov, E.A. Alkhimenko, T.A. Batkova, S.I. Grishin, A.V. Mamontov, G.I. Pravdikovskaya, E.A. Stroykov ISTOK, Moscow Region, Russia A.I. Shapovalov MRTI RAS, Moscow, Russia
	RPC "Istok" has created a number of electron injectors with voltage of 20-60kV and cathode diameter of 6-15mm of diode and triode designs. Injectors use the impregnated cathodes; the injector design allows rapid replacement of cathode assemblies. Injectors have been widely used in linear electron accelerators in Russia and Ukraine, in particular, in the sterilization accelerator center of JSC "MRTI RAS", Moscow, in the accelerator of the Russian Eye and Plastic Surgery Centre, Ufa. Have been proposed new input energy windows on the E11 wave, providing significant levels of transmission of the pulse power at high average power levels. Have been created two types of windows at 10-cm range, in which the ceramic disk made of ecologically clean alumina ceramic with diameter of 103mm and thickness of 13mm is used. In the first type of windows the heat transfer is provided from the peripheral portion, and in the second type of window – both from peripheral and central portions of the ceramic disk. These windows are used in accelerator of FSUE "NIIEFA" (St.Petersburg), installed at Izhora mill for testing the welding seals of atomic reactors and in accelerator of JSC "MRTI RAS".
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI041
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI044	Feasibility Study of an Ultrafast Electron Diffraction System in NSRRC	gun, injection, cathode, emittance	701
	P. Wang, K.C. Leou NTHU, Hsinchu, Taiwan N.Y. Huang, W.K. Lau, A.P. Lee NSRRC, Hsinchu, Taiwan
	It has been suggested that the MeV beam generated from a laser-driven photo-cathode rf gun can be used for ultrafast electron diffraction (UED). The feasibility of operating the NSRRC photo-cathode rf gun system for ultrashort bunch generation is being investigated. The results of space-charge tracking calculations show that a low emittance, few hundred femtoseconds MeV beam with reasonable bunch charge can be generated for single shot UED experiments. In this report, a preliminary design of this UED system will be discussed. X.J. Wang et al., in Proceedings of PAC'03, p.420.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI044
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI045	Beam Diagnostics E-GUN Test Stand at TARLA	gun, emittance, radiation, cathode	704
	Ç. Kaya, A.A. Aksoy, A. Aydin, V. Karakilic, Ö. Karslı, E. Kazancı, B. Koc, S. Kuday, E.Ç. Polat, I. Sara, M. Yildiz Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey S. Özkorucuklu Istanbul University, Istanbul, Turkey
	Funding: Work supported by Turkish State Planning Organization (Grant No: DPT2006K-120470) Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) facility, which is essentially proposed to generate oscillator mode FEL in 3-250 microns wavelengths range, will consist of totally normal conducting injector system with 250 keV beam energy, two superconducting RF accelerating modules in order to accelerate the beam 15-40 MeV. Continuous wave (CW) electron beam will provided by TARLA thermionic electron gun (E-GUN). Various aspects of the Thermionic EGUN test stand to deliver the necessary electron beam in terms of bunch charge, current, energy, emittance and profile for the beam diagnostic will be discussed. Primarily measurements results of electron beam energy loss and transverse orbit will be shown as well as beam image and shape measurements. On behalf of TARLA Collaboration
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI045
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI046	The Evolution of the Transverse Energy Distribution of Electrons from a GaAs Photocathode as a Function of its Degradation State	detector, cathode, laser, brightness	707
	L.B. Jones, B.L. Militsyn, T.C.Q. Noakes STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom H.E. Scheibler, A.S. Terekhov ISP, Novosibirsk, Russia
	The brightness of a photoelectron injector is fundamentally limited by the mean longitudinal and transverse energy distributions of the photoelectrons emitted from its photocathode, and the electron beam brightness is increased significantly if the mean values of these quantities are reduced. ASTeC have commissioned a Transverse Energy Spread Spectrometer (TESS – an experimental facility designed to measure these transverse and longitudinal energy distributions) which can be used for III-V semiconductor, alkali antimonide/telluride and metal photocathode research. GaAs photocathodes were activated in our photocathode preparation facility (PPF), then transferred to TESS under XHV conditions and progressively degraded through controlled exposure to oxygen. We present commissioning data and initial measurements showing the evolution of the transverse energy distribution of electrons from GaAs photocathodes as a function of their degradation state. Proc. FEL ’13, TUPPS033, 290-293 ** Proc. IPAC ’11, THPC129, 3185-3187
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI046
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI047	The Preparation of Atomically Clean Metal Surfaces for use as Photocathodes in Normally Conducting RF Guns	ion, gun, plasma, laser	711
	T.C.Q. Noakes, A.N. Hannah, K.J. Middleman, B.L. Militsyn, R. Valizadeh STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom S. Mistry Loughborough University, Leicestershre, United Kingdom
	Funding: Research supported by FP7 EuCard2 http://cern.ch/eucard2 This work reports a study of various alternative metal samples as candidate materials for use as photocathodes in normally conducting RF guns. Clean surfaces were prepared using Argon ion bombardment and quantum efficiency measured using a 265 nm UV LED light source with a picoammeter for drain current monitoring. Surface composition was studied using X-ray photoelectron spectroscopy and a Kelvin probe apparatus provided work function measurements. Data was taken both before and after annealing to 200°C, a temperature that is routinely achieved during RF gun vacuum baking. Ion bombardment typically leaves a very rough surface that can have a detrimental effect on beam emittance, so further work will focus on the use of Oxygen plasma cleaning of the best candidate alternative metals. An oxygen plasma treated Copper photocathode has been shown to produce an acceptable level of quantum efficiency in the VELA accelerator at Daresbury Laboratory.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI047
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI049	An Ultracold Electron Facility in Manchester	laser, emittance, space-charge, extraction	714
	Ö. Mete, R. Appleby, W. Bertsche, M.A. Harvey, G.X. Xia UMAN, Manchester, United Kingdom S. Chattopadhyay Cockcroft Institute, Warrington, Cheshire, United Kingdom A.J. Murray The University of Manchester, The Photon Science Institute, Manchester, United Kingdom
	An ultra-cold atom based electron source (UCAE) facility has been built in the Photon Science Institute (PSI), University of Manchester. In this paper, the key components and working principles of this source are introduced. Pre-commissioning status of this facility and the preliminary simulations results are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI049
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI050	Preliminary Study for an RF Photocathode based Electron Injector for AWAKE Project	emittance, laser, focusing, plasma	717
	Ö. Mete, G.X. Xia UMAN, Manchester, United Kingdom G. Burt Cockcroft Institute, Lancaster University, Lancaster, United Kingdom S. Chattopadhyay Cockcroft Institute, Warrington, Cheshire, United Kingdom
	AWAKE project, a proton driven plasma wakefield acceleration (PDPWA) experiment is approved by CERN. The PDPWA scheme consists of a seeding laser, a drive beam to establish the accelerating wakefields within the plasma cell; and a witness beam to be accelerated. The drive beam protons will be provided by the CERN's SPS. The plasma ionisation will be performed by a seeding laser and the drive beam protons to produce the accelerating wakefields. After establishing the wakefields, witness beam, namely, electron beam from a dedicated source should be injected into the plasma cell. The primary goal of this experiment is to demonstrate acceleration of a 5-15 MeV single bunch electron beam up to 1 GeV in a 10 m of plasma. This paper explores the possibility of an RF photocathode as the electron source for this PDPWA scheme based on the existing PHIN photoinjector at CERN. The modifications to the existing design, preliminary beam dynamics simulations in order to provide the required electron beam are presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI050
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI051	Measurements of the Longitudinal Energy Distribution of Low Energy Electrons	cathode, laser, experiment, simulation	720
	L.J. Devlin, O. Karamyshev, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom L.J. Devlin, O. Karamyshev, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom L.B. Jones, B.L. Militsyn, T.C.Q. Noakes STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: Work supported by STFC Cockcroft Core Grant No.ST/G008248/1 The Transverse Energy Spread Spectrometer (TESS) is an ASTeC experiment designed to measure the energy of electrons from different cathode materials. It is a dedicated test stand for future light sources. A full particle tracking code has been developed in the QUASAR Group, which simulates particle trajectories through TESS. Using this code it is possible to simulate different operational conditions of the experiment and cathode materials. The simulation results can then be benchmarked against experimental data to test the validity of the emission and beam transport model. Within this paper, results from simulation studies are presented and compared against experimental data as a collaboration within the Cockcroft Institute between ASTeC and the QUASAR Group for the case of measuring the longitudinal velocity distribution of electrons emitted from a gallium arsenide cathode using a grid structure as an energy filter.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI051
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI053	High Repetition Rate Ultrafast Electron Diffraction at LBNL	emittance, gun, experiment, laser	724
	D. Filippetto, M. Mellado Munoz, H.J. Qian, F. Sannibale, W. Wan, R.P. Wells, M.S. Zolotorev LBNL, Berkeley, California, USA
	Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231" Here we propose to use the APEX photo-gun as novel source for time-resolved electron diffraction studies. The electron source has been designed, built and successfully tested at LBNL. It combines a high accelerating field needed for bright beams, MeV electron energy essential for time resolution in gas-phase experiments and studies of bulk processes, together with continuous (CW) operations. Ultra-short electron pulses can be delivered with a maximum repetition rate of 186 MHz, enabling new science to be studied. We report the design of a dedicated electron diffraction beamline that fits in the space constraints of the APEX tunnel. Simulations of beam properties have been carried out with a genetic optimizer, showing 100 fs time resolution. Beam jitters in energy, time and position are currently being characterized, and a mitigation strategy via fast feedback loops is discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI053
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI055	APEX Present Experimental Results	cathode, gun, emittance, laser	730
	D. Filippetto, C.W. Cork, S. De Santis, L.R. Doolittle, G. Huang, R. Huang, W.E. Norum, C. F. Papadopoulos, G.J. Portmann, H.J. Qian, F. Sannibale, J.W. Staples, R.P. Wells LBNL, Berkeley, California, USA J. Yang TUB, Beijing, People's Republic of China
	Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231 The APEX electron source at LBNL combines high-repetition-rate and high beam brightness typical of photo-guns, delivering low emittance electron pulses at MHz frequency. Proving the high beam quality of the beam is an essential step for the success of the experiment. It would enable high repetition rate operations for brightness-hungry applications such as X-Ray FELs, and MHz ultrafast electron diffraction. A full 6D characterization of the beam phase space at the gun beam energy (750 keV) is foreseen in the first phase of the project. Diagnostics for low and high current measurements have been installed and tested, measuring the performances of different cathode materials in a RF environment with mA average current. A double-slit system allows the characterization of beam emittance at high charge and full current (mA). An rf deflecting cavity and a high precision spectrometer allow the characterization of the longitudinal phase space. Here we present the latest results at low and high repetition rate, discussing the tools and techniques used.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI055
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI057	Photoemission from III-V Semiconductor Cathodes	cathode, vacuum, photon, scattering	736
	S.S. Karkare Cornell University, Ithaca, New York, USA I.V. Bazarov, L. Cultrera, W.J. Schaff Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA X.G. Jin Institute for Advanced Research, Nagoya, Japan Y. Takeda Nagoya University, Nagoya, Japan
	Quantum efficiencies (QE) and mean transverse energies (MTE) of GaAs photocathodes grown using various techniques: metal-organic vapor phase epitaxy (MOVPE), molecular beam epitaxy (MBE), and atomic polishing have been compared and found to be identical. GaAs and GaInP based samples grown at Nagoya University were activated and measured in the Cornell ERL photoinjector. These were found to be in agreement with the samples measured at the ERL injector in KEK.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI057
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI058	Metal Plasmonic Nanostructures Functionalized by Atomic Layer Deposition of MgO for Photocathode Applications	cathode, vacuum, resonance, emittance	739
	S.V. Baryshev, S.P. Antipov, A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio, USA M.R. Savina, A.V. Zinovev ANL, Argonne, Illinois, USA E. Thimsen University of Minnesota, Minneapolis, USA
	Funding: Euclid TechLabs LLC acknowledges support from the DOE SBIR program, grant No. DE-SC0009572. To create high current, long lasting electron sources capable of providing sub-ps bunches, new photocathode concepts are sought. Most recently, plasmonic nanostructured metal surfaces or flat metal surfaces activated by an ultrathin MgO are under great attention. We report on a photocathode design combining these two approaches. It consists of plasmonic Ag nanoparticles (NPs) functionalized by 3 MgO monolayers (MLs). Ag NPs were synthesized by an aerosol method and MgO was grown by atomic layer deposition (ALD). The NPs geometry was tuned to obtain broadband >50% absorption in the entire blue range as evidenced by UV-vis. spectroscopy. The WF of 3 MgO MLs/Ag NPs multilayer was reduced by 1 eV compared to bare NPs, from 5 to 4 eV, as evidenced by UPS and Kelvin probe. Reduction by 1 eV is maximal for this pair of materials, and agrees well with experimental and theoretical findings. While the effect on WF is indeed significant, a special handling protocol for Ag before depositing MgO is a must. It would preserve a clean Ag surface with a WF of nearly 4 eV to achieve 3 eV upon ALD of MgO. This and other issues are under study to promote photocathode applications.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI058
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI064	First Test Results from SRF Photoinjector for the R&D ERL at BNL	gun, SRF, cathode, cavity	748
	D. Kayran, Z. Altinbas, D.R. Beavis, S.A. Belomestnykh, I. Ben-Zvi, J. Dai, S. Deonarine, D.M. Gassner, R.C. Gupta, H. Hahn, L.R. Hammons, C. Ho, J.P. Jamilkowski, P. Kankiya, N. Laloudakis, R.F. Lambiase, V. Litvinenko, G.J. Mahler, L. Masi, G.T. McIntyre, T.A. Miller, D. Phillips, V. Ptitsyn, T. Rao, T. Seda, B. Sheehy, K.S. Smith, A.N. Steszyn, T.N. Tallerico, R. Than, R.J. Todd, E. Wang, D. Weiss, M. Wilinski, W. Xu, A. Zaltsman BNL, Upton, Long Island, New York, USA S.A. Belomestnykh, I. Ben-Zvi, J. Dai, L.R. Hammons, V. Litvinenko, V. Ptitsyn Stony Brook University, Stony Brook, USA
	Funding: This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE and DOE grant at Stony Brook, DE-SC0005713. An ampere class 20 MeV superconducting Energy Recovery Linac (ERL) is presently under commissioning at Brookhaven National Laboratory (BNL). This facility enables testing of concepts relevant for high-energy coherent electron cooling, electron-ion colliders, and high repetition rate Free-Electron Lasers. The ERL will be capable of providing electron beams with sufficient quality to produce high repetition rate THz and X-ray radiation. When completed the SRF photoinjector will provide 2 MeV energy and 300 mA average beam current. The injector for the R&D ERL was installed in 2012, this includes a 704MHz SRF gun* with multi-alkali photocathode, cryo-system upgrade and a novel emittance preservation zigzag-like low energy merger system. We describe the design and major components of the R&D ERL injector then report the first experimental results and experiences learned in the first stage of beam commissioning of the BNL R&D ERL. * Wencan Xu et al., “Commissioning SRF gun for the R&D ERL at BNL”, IPAC2013 proceedings, WEPWO085.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI064
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI066	External Neutron Source for Research Reactor Based on Linear Accelerator and Beryllium Target	target, neutron, radiation, experiment	754
	V.P. Struev, A.A. Bogdanov, A.G. Golovkina, Yu.V. Kiselev, I.V. Kudinovich, A.I. Laikin, S.M. Rubanov KSRC, St. Petersburg, Russia A.G. Golovkina, I.V. Kudinovich St. Petersburg State University, St. Petersburg, Russia
	Nuclear research reactor “U-3” of Krylov State Research Center was operated as an experimental tool to study a radiation shield of small nuclear power plants, radiation resistance of its equipment including control system elements. Reactor thermal output power is 50 kW. Currently reactor modernization is being carried out, in the framework of which neutron lighting system that consists of a linear electron accelerator “UEL-10D” (10 MeV) and a beryllium target is implemented. At the present time the neutron yield from the target experiments are going on, some obtained experimental results are presented. Optimal target sizes with a view to neutron yield were defined.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI066
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI067	Beam Cooling Systems and Activities at GSI and FAIR	experiment, ion, pick-up, antiproton	757
	C. Dimopoulou GSI, Darmstadt, Germany
	Efficient and versatile beam cooling (electron and stochastic cooling) has been an indispensable ingredient for beam preparation and physics experiments at the GSI accelerator complex. The hot secondary beams emerging from the production targets can hardly be used, unless they are cooled. Beam stacking of low-abundant species relies on cooling. Cooling enables high-precision experiments with stored beams, counteracts the heating during internal target operation and controls decelerated beams. New challenges lie ahead within the FAIR project like (i) the ongoing integration downstream of the ESR of the low-energy CRYRING with its electron cooler, (ii) the developments for the demanding CR stochastic cooling system, (iii) the stacking scenarios with RF and stochastic cooling in the HESR/RESR. The function and parameters of the existing and future beam cooling systems are summarized. We report on the latest hardware developments as well as on improvements of the controls and operation software. Recent highlights and results from beam manipulations with cooling at GSI are shown. In focus are those benchmarking experiments, where the concepts for the new FAIR systems are verified. C. Dimopoulou on behalf of the GSI Beam Cooling Department, of the GSI Stored Beams Division and of the FAIR Project Team.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI067
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI070	2MeV Electron Cooler for COSY and HESR – First Results	proton, experiment, operation, heavy-ion	765
	V. Kamerdzhiev, U. Bechstedt, F.M. Esser, O. Felden, R. Gebel, A.J. Halama, F. Klehr, G. Langenberg, A. Lehrach, B. Lorentz, R. Maier, D. Prasuhn, K. Reimers, M. Retzlaff, R. Stassen, H. Stockhorst, R. Tölle FZJ, Jülich, Germany N. Alinovskiy, T.V. Bedareva, E.A. Bekhtenev, O.V. Belikov, V.N. Bocharov, V.V. Borodich, M.I. Bryzgunov, A.V. Bubley, V.A. Chekavinskiy, V.G. Cheskidov, B.A. Dovzhenko, A.I. Erokhin, M.G. Fedotov, A.D. Goncharov, K. Gorchakov, V.K. Gosteev, I.A. Gusev, G.V. Karpov, Y.I. Koisin, M.N. Kondaurov, V.R. Kozak, A.M. Kruchkov, A.D. Lisitsyn, I.A. Lopatkin, V.R. Mamkin, A.S. Medvedko, V.M. Panasyuk, V.V. Parkhomchuk, I.V. Poletaev, V.A. Polukhin, A.Yu. Protopopov, D.N. Pureskin, A.A. Putmakov, V.B. Reva, P.A. Selivanov, E.P. Semenov, D.V. Senkov, D.N. Skorobogatov, N.P. Zapiatkin BINP SB RAS, Novosibirsk, Russia J. Dietrich HIM, Mainz, Germany T. Katayama Nihon University, Narashino, Chiba, Japan L.J. Mao IMP, Lanzhou, People's Republic of China
	The 2 MeV electron cooler was installed in the COSY ring in the spring 2013. The new system enables electron cooling in the whole energy range of COSY. The electron beam is guided by longitudinal magnetic field all the way from the electron gun to the collector. This well-proven optics scheme was chosen because of the wide electron energy range of 0.025-2 MeV. The electrostatic accelerator consists of 33 individual sections of identical design. Electrical power to each section is provided by a cascade transformer. Electron beam commissioning and first studies using proton and deuteron beams were carried out. Electron cooling of proton beam up to 1662 MeV kinetic energy was demonstrated. Maximum electron beam energy achieved so far amounted to 1.25 MeV. Voltage up to 1.4 MV was demonstrated. The cooler was operated with electron current up to 0.5 A. The paper provides insights into the recent progress in high energy electron cooling at COSY and perspectives for the HESR ring at FAIR.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI070
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI073	Status of the HESR Electron Cooler Test Set-up	gun, diagnostics, solenoid, vacuum	771
	M.W. Bruker, K. Aulenbacher, J. Dietrich, S. Friederich, T. Weilbach HIM, Mainz, Germany K. Aulenbacher IKP, Mainz, Germany
	For the High Energy Storage Ring (HESR) at FAIR, it is planned to install an electron cooling device with a beam current of 3 A and a beam energy of 8 MeV. A test set-up was built at Helmholtz-Insitut Mainz (HIM) to conduct a feasibility study. One of the main goals of the test set-up is to evaluate the gun design proposed by TSL (Uppsala) with respect to vacuum handling, electric and magnetic fields, and the resulting beam parameters. Another purpose of the set-up is to reduce recuperation losses to less than 10^-5. To measure this quantity and to mitigate collection losses, a Wien filter has been designed and installed. Beam diagnostics will be carried out with a COSY-style beam position monitor. The latest progress of the project is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI073
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI074	Conceptual Project Relativistic Electron Cooler for FAIR/HESR	proton, high-voltage, acceleration, cathode	774
	V.V. Parkhomchuk, M.I. Bryzgunov, A.P. Denisov, V.M. Panasiuk, V.B. Reva BINP SB RAS, Novosibirsk, Russia K. Aulenbacher, J. Dietrich HIM, Mainz, Germany V. Kamerdzhiev FZJ, Jülich, Germany
	To develop a 4 MeV relativistic electron cooling system for the HESR storage ring, which is part of the future GSI facility FAIR, is proposed to further boost the luminosity even with strong heating effects of high-density internal targets. In addition the upgrade to 8 MeV of the relativistic electron cooler is essential for the future Electron Nucleon Collider (ENC@FAIR) project. The basic feature of the design are the power for magnet field coils at accelerating and decelerating column is generated by turbines (one option under investigation in this research group) operated on SF6 gas under pressure
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI074
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI075	COSY 2 MeV Cooler: Design, Diagnostic and Commissioning	controls, gun, ion, diagnostics	777
	V.B. Reva, N. Alinovskiy, T.V. Bedareva, E.A. Bekhtenev, O.V. Belikov, V.N. Bocharov, V.V. Borodich, M.I. Bryzgunov, A.V. Bubley, V.A. Chekavinskiy, V.G. Cheskidov, B.A. Dovzhenko, A.I. Erokhin, M.G. Fedotov, A.D. Goncharov, K. Gorchakov, V.K. Gosteev, I.A. Gusev, A.V. Ivanov, G.V. Karpov, Y.I. Koisin, M.N. Kondaurov, V.R. Kozak, A.D. Lisitsyn, I.A. Lopatkin, V.R. Mamkin, A.S. Medvedko, V.M. Panasyuk, V.V. Parkhomchuk, I.V. Poletaev, V.A. Polukhin, A.Yu. Protopopov, D.N. Pureskin, A.A. Putmakov, P.A. Selivanov, E.P. Semenov, D.V. Senkov, D.N. Skorobogatov, N.P. Zapiatkin BINP SB RAS, Novosibirsk, Russia J. Dietrich DELTA, Dortmund, Germany V. Kamerdzhiev, L.J. Mao FZJ, Jülich, Germany
	The 2 MeV electron cooling system for COSY-Julich was proposed to further boost the luminosity in presence of strong heating effects of high-density internal targets. The 2 MeV cooler is also well suited in the start up phase of the High Energy Storage Ring (HESR) at FAIR in Darmstadt. It can be used for beam cooling at injection energy and for testing new features of the high energy electron cooler for HESR. The COSY cooler is designed on the classic scheme of low energy coolers like cooler CSRm, CSRe, LEIR that was produced in BINP before. The electron beam is transported inside the longitudinal magnetic field along whole trajectory from an electron gun to a collector. This optic scheme is stimulated by the wide range of the working energies 0.025-2 MeV. The electrostatic accelerator consists of 33 individual unify section. Each section contains two HV power supply and power supply of the magnetic coils. The electrical power to each section is provided by a cascade transformer. This report describes the cooler design, diagnostics, control system and the result of the commissioning in BINP and FZJ at the different energies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI075
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI088	Beam Transport Experiments Using Gabor Lenses	beam-transport, experiment, focusing, space-charge	818
	K. Schulte, M. Droba, S. Klaproth, O. Meusel, D. Noll, U. Ratzinger IAP, Frankfurt am Main, Germany
	A prototype Gabor lens has successfully been tested at the GSI High Current Test Injector (HOSTI). The experiments comprised the investigation of an emittance dominated and a space-charge dominated beam transport. In particular, the high-current measurements represent a necessary step towards evaluating the focusing performance of the lens and to gain experience in a real accelerator environment. Besides the evaluation of the technical feasibility, the behavior of the electron cloud was characterized by the parameter analysis of the confined non-neutral plasma during beam transport measurements as well as subsequently performed diagnostic experiments. This contribution will present experimental results as well as numerical studies on an improved Gabor lens design for the possible application at the GSI High Current Injector (HSI) in the context of an upgrade program for FAIR. K. Schulte et al., Proc. of IPAC'13, Shanghai, China, 2013, THPWO021 **L. Dahl, Proc. of HIAT’09, Venice, Italy, 2009, FR-01
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI088
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOAA03	Extra Low ENergy Antiproton ring ELENA: From the Conception to the Implementation Phase	experiment, antiproton, emittance, extraction	910
	C. Carli, W. Bartmann, P. Belochitskii, H. Breuker, F. Butin, T. Eriksson, S. Maury, S. Pasinelli, G. Tranquille CERN, Geneva, Switzerland W. Oelert Johannes Gutenberg University Mainz, Institut für Physik, Mainz, Germany
	The Extra Low Energy Antiproton ring (ELENA) is a CERN project aiming at constructing a small 30 m circumference synchrotron to further decelerate antiprotons from the Antiproton Decelerator AD from 5.3 MeV to 100 keV. Controlled deceleration in a synchrotron equipped with an electron cooler to reduce emittances in all three planes will allow the existing AD experiments to increase substantially their antiproton capture efficiencies and render new experiments possible. The ELENA design is now well advanced and the project is moving to the implementation phase. Component design and construction are taking place at present for installation foreseen during the second half of 2015 and beginning of 2016 followed by ring commissioning until the end of 2016. New electrostatic transfer lines to the experiments will be installed and commissioned during the first half of 2017 followed by the first physics operation with ELENA. Basic limitations like Intra Beam Scattering limiting the emittances obtained under electron cooling and direct space charge effects will be reviewed and the status of the project will be reported.
	Slides TUOAA03 [4.963 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOAA03
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUYA01	First Experience with Electron Lenses for Beam-beam Compensation in RHIC	solenoid, emittance, hadron, proton	913
	W. Fischer, Z. Altinbas, D. Bruno, M.R. Costanzo, X. Gu, J. Hock, A.K. Jain, Y. Luo, C. Mi, R.J. Michnoff, T.A. Miller, A.I. Pikin, T. Samms, Y. Tan, R. Than, P. Thieberger, S.M. White BNL, Upton, Long Island, New York, USA
	Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH10886 with the U.S. Department of Energy. The head-on beam-beam interaction is the dominant luminosity limiting effect in polarized proton operation in RHIC. To mitigate this effect two electron lenses were installed in the two RHIC rings. We summarize the hardware and electron beam commissioning results to date, and report on the first experience with the electron-hadron beam interaction. In 2014 RHIC is operating with gold beams only. In this case the luminosity is not limited by head-on beam-beam interactions and compensation is not necessary. The goals of this year’s commissioning efforts are a test of all instrumentation; the demonstration of electron and gold beam overlap; the demonstration of electron beam parameters that are sufficiently stable to have no negative impact on the gold beam lifetime; and the measurement of the tune footprint compression from the beam overlap. With these demonstrations, and a lattice with a phase advance that has a multiple of 180 degrees between the beam-beam interaction and electron lens locations, head-on beam-beam compensation can be commissioned in the following year with proton beams.
	Slides TUYA01 [11.776 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUYA01

Paper

Title

Other Keywords

Page

MOYAA01

Innovative Ideas for Single-pass FELs

FEL, operation, undulator, photon

12

T. Hara
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan

SASE FELs are a powerful light source in short wavelengths from VUV to X-ray regions to investigate matters and phenomena. SASE was first experimentally obtained in 2000 at DESY TTF with an output wavelength of 10⁹ nm. Subsequently, FLASH, LCLS and SACLA have achieved lasing in VUV, soft X-rays and hard X-rays. Although SASE has already been widely used for many application experiments in broad scientific fields, its spiky spectrum and time structures due to the lack of longitudinal coherence sometimes become problematic. To improve its longitudinal coherence, various ideas have been proposed and some of them are already demonstrated experimentally, such as a self-seeded scheme, high-gain harmonic generation (HGHG) and echo-enabled harmonic generation (EEHG). There is also another direction of developments to enhance the capability and potentiality of SASE, for example short pulse generation and two-color lasing. This talk will review recent innovative ideas of short wavelength FELs together with their experimental results.

Slides MOYAA01 [10.701 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOYAA01

Export •

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

MOZB02

Advances in Photocathodes for Accelerators

emittance, cathode, laser, experiment

48

L. Cultrera
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

This talk reviews advances in photocathode technology for accelerators: cathodes demonstrating record average currents and deliverable charge, possessing ultra-low intrinsic emittance and sub-picosecond response time. It addresses the grand challenge to combine all these useful properties into a single photoemitter - one that is being actively pursued by the research community.

Slides MOZB02 [4.354 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOZB02

Export •

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

MOPRO001

Upgrade Status of Injector LINAC for SuperKEKB

positron, linac, emittance, gun

59

T. Miura, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, Y. Funakoshi, K. Furukawa, T. Higo, H. Honma, R. Ichimiya, N. Iida, M. Ikeda, E. Kadokura, H. Kaji, K. Kakihara, T. Kamitani, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, F. Miyahara, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, Y. Ohnishi, S. Ohsawa, F. Qiu, M. Satoh, T. Shidara, A. Shirakawa, H. Sugimoto, T. Suwada, T. Takenaka, M. Tanaka, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou
KEK, Ibaraki, Japan
D. Satoh
TIT, Tokyo, Japan

The SuperKEKB collider is under construction to achieve 40-times higher luminosity than that of previous KEKB collider. The injector LINAC should provide high-intensity and low-emittance beams of 7-GeV electron and 4-GeV positron for SuperKEKB based on a nano-beam scheme. A photocathode RF-gun for low emittance electron beam has been already installed and the commissioning has started. The construction of positron capture section using a flux-concentrator and the dumping ring for low emittance positron beam is in progress. The simultaneous top-up injections to four storage-rings including photon factories is also required. In the upstream of dumping ring, the compatible optics between positron and electron has been designed. In the downstream of dumping ring, RF phase, focusing, and steering magnets will be switched by pulse to pulse against each beam-mode for optimising beam-transportation. This paper describes recent upgrade status toward the SuperKEKB.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO001

Export •

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

MOPRO003

Towards Stable Acceleration in Linacs

klystron, acceleration, bunching, linac

65

A. Dubrovskiy
Private Address, Geneve, Switzerland

Ultra-stable and -reproducible high-energy particle beams with short bunches are needed in novel linear accelerators and, in particular, in the Compact Linear Collider CLIC. A passive beam phase stabilization system based on a bunch compression with a negative transfer matrix element R56 and acceleration at a positive off-crest phase is proposed. The motivation and expected advantages of the proposed scheme are outlined.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO003

Export •

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

MOPRO005

Progress on the Interaction Region Design and Detector Integration at JLab’s MEIC

detector, ion, collider, focusing

71

V.S. Morozov, P.D. Brindza, A. Camsonne, Y.S. Derbenev, R. Ent, D. Gaskell, F. Lin, P. Nadel-Turonski, M. Ungaro, Y. Zhang, Z.W. Zhao
JLab, Newport News, Virginia, USA
C. Hyde, K. Park
Old Dominion University, Norfolk, Virginia, USA
M.K. Sullivan
SLAC, Menlo Park, California, USA
Z.W. Zhao
UVa, Charlottesville, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357.
One of the unique features of JLab's Medium-energy Electron-Ion Collider (MEIC) is a full-acceptance detector with a dedicated, small-angle, high-resolution detection system, capable of covering a wide range of momenta (and charge-to-mass ratios) with respect to the original ion beam to enable access to new physics. We present an interaction region design developed with close integration of the detection and beam dynamical aspects. The dynamical aspect of the design rests on a symmetry-based concept for compensation of non-linear effects. The optics and geometry have been optimized to accommodate the detection requirements and to ensure the interaction region's modularity for ease of integration into the collider ring lattices. As a result, the design offers an excellent detector performance combined with the necessary provisions for non-linear dynamical optimization.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO005

Export •

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

MOPRO006

Preservation of Electron Polarization in the MEIC Collider Ring

polarization, collider, injection, solenoid

74

F. Lin, Y.S. Derbenev, V.S. Morozov, Y. Zhang
JLab, Newport News, Virginia, USA
D.P. Barber
DESY, Hamburg, Germany

Funding: U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357.
A highly longitudinally-polarized (over 70%) electron beam is required by the nuclear physics programme of the Medium Energy Electron-Ion Collider (MEIC) at Jefferson Lab (JLab). To achieve this goal, a highly vertically-polarized electron beam is injected from the CEBAF. The polarization will be vertical in the arcs to avoid spin diffusion, and longitudinal at the collision points. The polarization rotation will be accomplished by using a total of four spin rotators, each of which consists of a set of solenoids and dipoles, placed at the ends of two arcs. The polarization configuration cancels the 1st order spin perturbation in the solenoids for the off-momentum particles and significantly reduces the synchrotron sideband resonances. In order to compensate the net Sokolov-Ternov depolarization effect, especially at higher energies, a continuous injection of a polarized electron beam from the CEBAF is being considered. We consider to perform a moderate spin matching in some key regions to extend the polarization lifetime so that the continuous injection can work more efficiently, while not imposing a burden on the optics design of the collider ring.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO006

Export •

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

MOPRO007

GPU-Accelerated Long-Term Simulations of Beam-Beam Effects in Colliders

GPU, luminosity, simulation, collider

77

B. Terzić, F. Lin, V.S. Morozov, Y. Roblin, H. Zhang
JLab, Newport News, Virginia, USA
M. Aturban, D. Ranjan, M. Zubair
ODU CS, Norfolk, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
We present an update on the development of the new code for long-term simulation of beam-beam effects in particle colliders. The underlying physical model relies on a matrix-based arbitrary-order particle tracking (including a symplectic option) for beam transport and the generalized Bassetti-Erskine approximation for beam-beam interaction. The computations are accelerated through a parallel implementation on a hybrid GPU/CPU platform. With the new code, previously computationally prohibitive long-term simulations become tractable. The new code will be used to model the proposed Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO007

Export •

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

MOPRO011

Employing Twin Crabbing Cavities to Address Variable Transverse Coupling of Beams in the MEIC*

solenoid, proton, cavity, coupling

80

A. Castilla
DCI-UG, León, Mexico
A. Castilla, J.R. Delayen, V.S. Morozov, T. Satogata
JLab, Newport News, Virginia, USA
A. Castilla, J.R. Delayen, V.S. Morozov, T. Satogata
ODU, Norfolk, Virginia, USA

Funding: *Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The design strategy of the Medium Energy Electron-Ion Collider (MEIC) at Jefferson Lab contemplates both matching of the emittance aspect ratios and a 50 mrad crossing angle along with crab crossing scheme for both electron and ion beams over the energy range (√s=20-70 GeV) to achieve high luminosities at the interaction points (IPs). However, the desired locations for placing the crabbing cavities may include regions where the transverse degrees of freedom of the beams are coupled with variable coupling strength that depends on the collider rings’ magnetic elements (solenoids and skew quadrupoles). In this work we explore the feasibility of employing twin rf dipoles that produce a variable direction crabbing kick to account for a range of transverse coupling of both beams.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO011

Export •

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

MOPRO012

Simulating Fast Beam-Ion Instability Studies in FFAG-Based ERHIc Rings

ion, simulation, linac, lattice

83

G. Wang, V. Litvinenko, Y. Luo
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.
In an electron accelerator, ions generated from the residual gas by the circulating electrons act back to the trailing electrons. Under unfavorable conditions this feed-back can cause unstable motion of the electron bunches, the process known as the fast beam ion instability. Current eRHIC design has two FFAG rings transporting 21 electron beams at 11 different energies. In this study, we use numerical simulation to investigate the fast ion instability in this complicated system, compare the simulation results with theory and discuss possible measures to mitigate the instability.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO012

Export •

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

MOPRO013

Present Status of Coherent Electron Cooling Proof-of-Principle Experiment

ion, cavity, gun, experiment

87

V. Litvinenko, Z. Altinbas, D.R. Beavis, S.A. Belomestnykh, I. Ben-Zvi, K.A. Brown, J.C. Brutus, A.J. Curcio, L. DeSanto, C. Folz, D.M. Gassner, H. Hahn, Y. Hao, C. Ho, Y. Huang, R.L. Hulsart, M. Ilardo, J.P. Jamilkowski, Y.C. Jing, F.X. Karl, D. Kayran, R. Kellermann, N. Laloudakis, R.F. Lambiase, G.J. Mahler, M. Mapes, W. Meng, R.J. Michnoff, T.A. Miller, M.G. Minty, P. Orfin, A. Pendzick, I. Pinayev, F. Randazzo, T. Rao, J. Reich, T. Roser, J. Sandberg, T. Seda, B. Sheehy, J. Skaritka, L. Smart, K.S. Smith, L. Snydstrup, A.N. Steszyn, R. Than, C. Theisen, R.J. Todd, J.E. Tuozzolo, E. Wang, G. Wang, D. Weiss, M. Wilinski, T. Xin, W. Xu, A. Zaltsman
BNL, Upton, Long Island, New York, USA
G.I. Bell, J.R. Cary, K. Paul, I.V. Pogorelov, B.T. Schwartz, A.V. Sobol, S.D. Webb
Tech-X, Boulder, Colorado, USA
C.H. Boulware, T.L. Grimm, R. Jecks, N. Miller
Niowave, Inc., Lansing, Michigan, USA
A. Elizarov
SUNY SB, Stony Brook, New York, USA
M.A. Kholopov, P. Vobly
BINP SB RAS, Novosibirsk, Russia
P.A. McIntosh, A.E. Wheelhouse
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: Work supported by Stony Brook University and by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The Coherent Electron Cooling Proof of Principle (CeC PoP) system is being installed in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. It will demonstrate the ability of relativistic electrons to cool a single bunch of heavy ions in RHIC. This technique may increase the beam luminosity by as much as tenfold. Within the scope of this experiment, a 112 MHz 2 MeV Superconducting Radio Frequency (SRF) electron gun coupled with a cathode stalk mechanism, two normal conducting 500 MHz single-cell bunching cavities, a 704 MHz 20 MeV 5-cell SRF cavity and a helical undulator will be used. In this paper, we provide an overview of the engineering design for this project, test results and discuss project status and plansd.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO013

Export •

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

MOPRO015

Advances in Coherent Electron Cooling

hadron, FEL, bunching, kicker

91

V. Litvinenko, Y. Hao, Y.C. Jing, D. Kayran, G. Wang
BNL, Upton, Long Island, New York, USA
G.I. Bell, I.V. Pogorelov, B.T. Schwartz, A.V. Sobol, S.D. Webb
Tech-X, Boulder, Colorado, USA
D.L. Bruhwiler
RadiaSoft LLC, Boulder, Colerado, USA
A. Elizarov
SUNY SB, Stony Brook, New York, USA
D.F. Ratner
SLAC, Menlo Park, California, USA
O.A. Shevchenko
BINP SB RAS, Novosibirsk, Russia

This paper will be focused on advances and challenges in cooling of high-energy hadron – and potentially heavy lepton-beams. Such techniques are required to improve quality of hadron beams and for increasing the luminosity in hadron and electron-hadron colliders. In contrast with light leptons, which have very strong radiation damping via synchrotron radiation, the hadrons radiate very little (even in 7TeV LHC) and require additional cooling mechanism to control growth of their emittances. I will discuss the physics principles of revolutionary, but untested, technique: the coherent electron cooling (CeC). Further, current advances and novel CeC schemes will be presented as well as the status of preparation at Brookhaven National Laboratory for the CeC demonstration experiment.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO015

Export •

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

MOPRO024

The Beam Test for the Ti Extraction Window Damage

extraction, experiment, radiation, kicker

119

T. Mimashi, N. Iida, M. Kikuchi
KEK, Ibaraki, Japan

For the SuperKEKB beam abort system, the Ti extraction window will be used. The damage of the extraction window was estimated with KEKB electron beam. Thin Ti plate and Ti alloy plate were tested as candidates of extraction window material. The damages were observed as a function of beam current. From this experiment, the maximum charge density at the extraction window is determined.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO024

Export •

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

MOPRO036

Beam Life Time and Stability Studies for ELENA

antiproton, emittance, simulation, vacuum

154

J. Resta-López, O. Karamyshev, D. Newton, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
O. Karamyshev, D. Newton, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
J. Resta-López
IFIC, Valencia, Spain

Funding: Work supported by the EU under Grant Agreement 624854 and the STFC Cockcroft Institute Core Grant No. ST/G008248/1.
The Extremely Low ENergy Antiproton ring (ELENA) is a small synchrotron equipped with an electron cooler, which shall be constructed at CERN to decelerate antiprotons to energies as low as 100 keV. At such low energies it is very important to carefully take contributions from electron cooling and heating effects (e.g. on the residual gas) into account. Detailed investigations into the ion kinetics under consideration of effects from electron cooling and scattering on the residual gas have been carried out using the BETACOOL code. In this contribution a consistent explanation of the different physical effects acting on the beam in ELENA is given. Beam lifetime, equilibrium momentum spread and emittance are all estimated based on numerical simulations. Finally, optimum machine settings are presented as a result of optimization studies.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO036

Export •

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

MOPRO054

Commissioning progress of the Femto-slicing Project at SOLEIL

laser, wiggler, radiation, synchrotron

206

M. Labat, H.B. Abualrob, P. Betinelli-Deck, A. Buteau, N. Béchu, L. Cassinari, M.-E. Couprie, F. Dohou, C. Herbeaux, Ph. Hollander, J.-F. Lamarre, C. Laulhé, A. Lestrade, J. Lüning, O. Marcouillé, J.L. Marlats, T. Moreno, P. Morin, A. Nadji, L.S. Nadolski, D. Pédeau, P. Prigent, S. Ravy, J.P. Ricaud, M. Ros, P. Roy, M.G. Silly, F. Sirotti, K. Tavakoli, M.-A. Tordeux, D. Zerbib
SOLEIL, Gif-sur-Yvette, France

The femtoslicing project at SOLEIL is currently under commissioning. It will enable to serve several beamlines with 100 fs FWHM long pulses of soft and hard X-rays with reasonable flux and with a 1 kHz repetition rate. It is based on the interaction of a femtosecond Ti:Sa laser with electrons circulating in the magnetic field of a modulator wiggler, that provides the electron beam energy modulation on the length scale of the laser pulse. The optimization of the interaction is performed using two dedicated diagnostics stations. The first one, operating in the Infra-Red (IR) is installed in the tunnel and allows the adjustment of the temporal, spectral and spatial overlap between the laser and the electron beam. The second one, located in the IR-THz AILES beamline, measures the intensity of the terahertz (THz) radiation emitted by the local dip structure produced in the core electron beam after interaction. This second setup provides refined optimization of the interaction. This paper describes the layout of these diagnostics and gives first results and characterization of the slicing experiment at SOLEIL.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO054

Export •

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

MOPRO061

Study of the Beam Lifetime at the Synchrotron Light Source DELTA

scattering, synchrotron, vacuum, simulation

222

M.A. Jebramcik, H. Huck, S. Khan, R. Molo
DELTA, Dortmund, Germany

DELTA is a 1.5-GeV synchrotron light source operated by the TU Dortmund University. The beam lifetime, which is a critical issue for user operation of a light source, was studied experimentally and by simulation for different operation modes, i.e. single-bunch and multibunch fill patterns and for different beam currents. The electron loss rate is dominated by residual-gas scattering (Coulomb scattering and Bremsstrahlung) and by electron-electron scattering (Touschek effect). Since these processes depend in different ways on the momentum acceptance of the storage ring, a variation of the RF cavity voltage allows to disentangle their respective contributions to the total loss rate. The experimental results lead to a consistent picture for different operation modes with a characteristic dependence of the residual-gas pressure on the beam current.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO061

Export •

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

MOPRO066

Status of FLUTE

laser, gun, linac, diagnostics

231

M. Schuh, I. Birkel, A. Borysenko, A. Böhm, N. Hiller, E. Huttel, S. Höninger, V. Judin, S. Marsching, A.-S. Müller, A.-S. Müller, A.-S. Müller, S. Naknaimueang, M.J. Nasse, R. Rossmanith, R. Ruprecht, M. Schwarz, M. Weber, P. Wesolowski
KIT, Karlsruhe, Germany
R.W. Aßmann, M. Felber, K. Flöttmann, M. Hoffmann, H. Schlarb
DESY, Hamburg, Germany
H.-H. Braun, R. Ganter, V. Schlott, L. Stingelin
PSI, Villigen PSI, Switzerland

FLUTE, a new linac-based test facility and THz source is currently being built at the Karlsruhe Institute of Technology (KIT) in collaboration with DESY and PSI. It consists of an RF photo gun and a traveling wave linac accelerating electrons to beam energies of ~41 MeV in the charge range from a few pC up to 3 nC. The electron bunch will then be compressed in a magnetic chicane in the range of 1 - 300 fs, depending on the charge, in order to generate coherent THz radiation with high peak power. An overview of the simulation and hardware status is given in this contribution.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO066

Export •

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

MOPRO067

Analytic Calculation of Electric Fields of Coherent THz Pulses

radiation, synchrotron, synchrotron-radiation, shielding

234

M. Schwarz, P. Basler, M. Guenther, A.-S. Müller, M. von Borstel
KIT, Karlsruhe, Germany
M.T. Schmelling
MPI-K, Heidelberg, Germany

The coherently emitted electric field pulse of a short electron bunch is obtained by summing the fields of the individual electrons, taking phase differences due to different longitudinal positions into account. For an electron density, this sum becomes an integral over the charge density and frequency spectrum of the emitted radiation, which, however, is difficult to evaluate numerically. In this paper, we present a fast analytic method valid for arbitrary bunch shapes. We also include shielding effects of the beam pipe and consider ultra-short bunches, where the high frequency part of the coherent synchrotron spectrum is cut-off not by the inverse bunch length but by the critical frequency of synchrotron radiation. Our technique is applied to bunches, simulated simulated for the linac-based FLUTE accelerator test facility at KIT.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO067

Export •

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

MOPRO073

Design of Iranian Light Source Facility RF Shielded Bellows

impedance, vacuum, storage-ring, wakefield

252

H. Ghasem
IPM, Tehran, Iran
J. Etemad Moghadam
ILSF, Tehran, Iran

Total impedance is one of the most effective parameters for proper operation of an accelerator system. This quantity is evaluated with the summation of individual component impedance of the vacuum pipe and is desired to be as low as possible. The bellows have very significant effects on total impedance of the accelerator systems particularly synchrotron light source storage rings. Design of the bellow for Iranian Light Source Facility (ILSF) with a practical approach for fabrication has been down. Minimization of the total impedance budget, loss factor and the resulting wake field due to the passage of 400 mA electron beam is the main goal of our design.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO073

Export •

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

MOPRO078

The SPARC_LAB Thomson Source Commissioning

laser, photon, linac, emittance

267

C. Vaccarezza, D. Alesini, M.P. Anania, M. Bellaveglia, E. Chiadroni, D. Di Giovenale, G. Di Pirro, M. Ferrario, A. Gallo, G. Gatti, R. Pompili, S. Romeo, F. Villa
INFN/LNF, Frascati (Roma), Italy
A. Bacci, C. Curatolo, D.T. Palmer, V. Petrillo, A.R. Rossi, L. Serafini, P. Tomassini
Istituto Nazionale di Fisica Nucleare, Milano, Italy
P. Cardarelli, G. Di Domenico, M. Gambaccini
INFN-Ferrara, Ferrara, Italy
A. Cianchi
INFN-Roma II, Roma, Italy
P. Delogu
INFN-Pisa, Pisa, Italy
F. Filippi, A. Giribono
INFN-Roma, Roma, Italy
B. Golosio, P. Oliva
INFN-Cagliari, Monserrato (Cagliari), Italy
A. Mostacci
Rome University La Sapienza, Roma, Italy

The SPARC_LAB Thomson source is presently under commissioning at LNF. An electron beam of energy between 30-150 MeV collides head-on with the laser pulse provided by the Ti:Sapphire laser FLAME, characterized in this phase by a length of 6 ps FWHM and by an energy ranging between 1 and 5 J. The key features of this system are the wide range of tunability of the X-rays yield energy, i.e. 20-500 keV, and the availability of a coupled quadrupole and solenoid focusing system, allowing to reach an electron beam size of 10-20 microns at the interaction point. The experimental results obtained in the February 2014 shifts are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO078

Export •

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

MOPRO083

Design Study of High Brilliant Optics at the SPring-8 Storage Ring

emittance, photon, brilliance, optics

283

Y. Shimosaki, T. Aoki, K. Fukami, K.K. Kaneki, K. Kobayashi, M. Masaki, C. Mitsuda, H. Ohkuma, M. Shoji, K. Soutome, S. Takano, M. Takao
JASRI/SPring-8, Hyogo-ken, Japan

At the SPring-8 storage ring, design study of beam optics concentrating particularly on increasing brilliance, not flux density, is in progress besides continuous efforts of increasing both brilliance and flux density for the user optics. The natural emittances are theoretically reduced from 2.41 nmrad at 8 GeV to 2.27 nmrad (8 GeV), 1.78 nmrad (7 GeV) and 1.33 nmrad (6 GeV) by utilizing an emittance damping effect by the insertion devices. The designed optics has experimentally been examined at 6 GeV, and the electron beam parameters have been confirmed by measurements at the diagnostics beamlines.
* Y. Shimosaki et al., “New Optics with Emittance Reduction at the SPring-8 Storage Ring”, IPAC13, MOPEA027.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO083

Export •

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

MOPRO091

Fundamental Limits of Velocity Bunching of High-brightness Electron Beams

bunching, emittance, cavity, gun

304

A. Opanasenko, V.V. Mytrochenko
NSC/KIPT, Kharkov, Ukraine
V.A. Goryashko, V. Zhaunerchyk
Uppsala University, Uppsala, Sweden
P.M. Salen
FYSIKUM, AlbaNova, Stockholm University, Stockholm, Sweden

The interest in superradiant THz sources based on the coherent transition, synchrotron or undulator radiation grows continuously and such sources require high-quality electron bunches with low emittance, high charge and sub-picosecond (sub-ps) duration. Since accelerator-based THz sources are usually driven by relatively low energy electron bunches of a few tens of MeV, space-charge makes bunch compression to sub-ps level very challenging. In the present work we investigate the feasibility of ballistic bunching down to sub-ps duration while preserving the transverse phase-space quality. We found that in order to compensate for the nonlinear dependency of the arrival time on the energy as well as bunch deformations induced by space-charge effects, one needs to apply a nonlinear energy chirp. This chirp permits to maximize the bunch compression and can be realized by exciting a cavity with higher harmonics of the fundamental frequency. Issues related to synchronizing the harmonics are discussed and the analytical analysis is complemented by simulations with PARMELA.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO091

Export •

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

MOPRO105

Study of Ultra-low Emittance Design for SPEAR3

dipole, emittance, sextupole, quadrupole

337

M.-H. Wang, R.O. Hettel, X. Huang, T. Rabedeau, J.A. Safranek, K. Tian
SLAC, Menlo Park, California, USA

Funding: Work supported by the US Department of Energy under contract number: DE-AC02-76SF00515
Since its 2003 construction, the SPEAR3 synchrotron light source at SLAC has continuously improved its performance by raising beam current, top-off injection, small alpha and smaller emittance. This makes SPEAR3 one of the most productive light sources in the world. Now to further enhance the operation of SPEAR3, we are looking into the possibility of converting SPEAR3 to a multi-bend achromat storage ring within its site constraint.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO105

Export •

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

MOPRO109

Beam Loss Studies for the KEK Compact-ERL

scattering, simulation, cavity, beam-losses

349

O. Tanaka, T. Furuya, K. Harada, N. Nakamura, H. Sakai, M. Shimada, K. Umemori
KEK, Ibaraki, Japan
E. Cenni
Sokendai, Ibaraki, Japan

Beam losses due to eﬀects of Touschek, residual gas, intra-beam scattering, and field emission were studied for the KEK compact Energy Recovery Linac (cERL), which is now under commissioning. By studying the beam losses of cERL, we can better understand the loss mechanisms, estimate the beam loss rates, and localize potentially dangerous areas of the beamline for the future 3GeV ERL project. The goal is to achieve a safety low-emittance and high-current beams operation which can help contribute to the beam loss study under 3GeV ERL project. We used existing and modiﬁed ELEGANT routine to perform the simulations. We also developed a MATLAB data analysis algorithm to handle the large amount of information that is outputted from the program. The data obtained then compared with the theoretical estimation to judge the computation’s accuracy.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO109

Export •

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

MOPRO114

Particle Tracking Simulations with FLUKA for DESY FLASH and EXFEL

radiation, neutron, simulation, photon

363

V.G. Khachatryan, V.H. Petrosyan, A. Sargsyan, A.V. Tsakanian
CANDLE SRI, Yerevan, Armenia

The objective of the study is the simulation of the produced secondary radiation properties when the electron beam halo particles hit collimator walls. Using particle tracking simulation code FLUKA the European XFEL electron beam interaction with the titanium collimator and copper absorber of the undulator intersections as well as FLASH beam interaction with the tapered collimator were simulated. Absorbed dose spatial distribution in the material of the collimators was simulated for the total secondary radiation and its important photon and neutron components. Residual dose rate after irritation of the collimator material by the electron beam was calculated.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO114

Export •

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

MOPRO115

A Low Energy Electron-Scrapersystem for the S-DALINAC Injector

linac, acceleration, controls, target

366

L.E. Jürgensen, T. Bahlo, C. Burandt, F. Hug, T. Kürzeder, N. Pietralla, T. Schösser, C. Ungethüm
TU Darmstadt, Darmstadt, Germany

Funding: Work supported by DFG through SFB 634
The S-DALINAC is the superconducting linear accelerator of the Institut für Kernphysik at Technische Universität Darmstadt. It delivers an electron beam with energies up to 130 MeV. In order to improve the energy spread and the energy stability of the beam for further acceleration a new scrapersystem has been developed and installed between the 10 MeV injector and the main linac. The system was designed to ensure an energy spread of dE < 10^-03. After installation several tests have taken place, the results will be presented in this work.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO115

Export •

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

MOPME013

A Python Poisson Solver for 3D Space Charge Computations in Structures with Arbitrary Shaped Boundaries

simulation, rfq, space-charge, ion

406

G. Pöplau, C. Potratz
COMPAEC e.G., Rostock, Germany

Numerical techniques in the field of particle accelerators are mainly driven by the design of next-generation accelerators: The need for higher simulation complexity and the necessity for more and more specialized algorithms arises from the ever increasing need to include a broader range of physical effects and geometrical details in a computer simulation. This, on the other hand requires fast and reliable simulation tools for a limited user base. Therefore, new approaches in simulation software development are necessary to provide useful tools that are well-suited for the task at hand and that can be easily maintained and adapted by a small user community. We show how Python can be used to solve numerical problems arising from particle accelerator design efficiently. As model problem, the computation of space charge effects of a bunch in RFQs including the vane geometry was chosen and a suited solver was implemented in Python.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME013

Export •

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

MOPME019

Study of a Fast Convolution Method for Solving the Space Charge Fields of Charged Particle Bunches

simulation, space-charge, ion, electromagnetic-fields

418

D. Zheng, A. Markoviḱ, G. Pöplau, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany

The kernel of beam dynamics simulations using the particle-in-cell (PIC) model is the solution of Poisson's equation for the electric potential. A very common way to solve Poisson's equation is to use the convolution of charge density and Green's function, the so-called Green's function method. Additionally, the integrated Green's function method* is being used in order to achieve a higher accuracy. For both methods, the convolutions are done using fast Fourier transform based on the convolution theorem. However, the construction of the integrated Green's function and the further convolution is still very time-consuming. The computation can be accelerated without loosing precision if the calculation of Green’s function values is limited to that part of the computational domain with non-zero grid charge density. In this paper we present a general numerical study of these Green's function methods for computing the potential of different bunches: The results can also be used in other simulation codes to improve efficiency.
* J. Qiang, S. Lidia, R. D. Ryne, and C. Limborg-Deprey, “A Three-Dimensional Quasi-Static Model for High Brightness Beam Dynamics simulation,” Phys. Rev. ST Accel. Beams, vol 9, 044204 (2006).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME019

Export •

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

MOPME023

A High Precision Particle-moving Algorithm for Particle-in-cell Simulation of Plasma

simulation, cyclotron, plasma, experiment

427

X.F. Li, D.Z. Chen, D. Li, H.K. Yue
HUST, Wuhan, People's Republic of China

A new particle-moving algorithm for particle-in-cell simulation of plasma is developed based on the Linear Multistep Method. The conventional and the new algorithms are investigated by numerical experiments, which are conducted in three typical fashions of the electron motions in electromagnetic fields, that is, cyclotron in homogeneous magnetic field, drift in field and motions in inhomogeneous magnetic field. The new algorithm not only improves the accuracy but also relaxes the time step condition for the simulation. It can increase the computation efficiency.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME023

Export •

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

MOPME025

New Possibilities of MultP-M Code

simulation, multipactoring, RF-structure, operation

433

M. Gusarova, S. Khudyakov, I.I. Petrushina, Ya.V. Shashkov
MEPhI, Moscow, Russia

Implementation and Testing of the new module package for geometry import of the MultP-M 3D code for multipacting prediction was performed. The results of simulations for the coaxial line specimen using this new module are presented. These results are compared with analytical calculations and experimental data.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME025

Export •

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

MOPME026

IBS Simulations with Compute Unified Device Architecture (CUDA) Technology

scattering, simulation, GPU, factory

436

S.A. Glukhov, E.B. Levichev, S.A. Nikitin, P.A. Piminov, D.N. Shatilov, S.V. Sinyatkin
BINP SB RAS, Novosibirsk, Russia

A program code for 6D tracking has been developed taking into account IBS (Intra-Beam Scattering) and Touschek effect and using Monte-Carlo method. The simulation algorithm has been developed on the basis of well-known IBS theory presented in (*). The resulting program can be executed using GPGPU devices (General-Purpose Graphics Processing Units) supporting CUDA technology (Compute Unified Device Architecture).
* J. Le Duff, Single and multiple Touschek effects // Published in In Rhodos 1993, Advanced accelerator physics, vol. 2 573-586. CERN Geneva - CERN-95-06 (95/11,rec. Mar.96) 1993. p. 573-586.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME026

Export •

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

MOPME029

Simulation of Low Energy Charged Particle Beams

simulation, cyclotron, extraction, quadrupole

442

O. Karamyshev, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
O. Karamyshev, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Low energy particle beams pose specific challenges to simulation codes and experiments alike as a number of effects become important that can often be neglected at higher beam energies, including e.g. space-charge or fringe field effects. The optimization of low energy charged particle beam transport through arbitrary electromagnetic fields is the purpose of a code aimed at tracking low-energy particles from the sub-eV to the MeV energy range with high precision. The code is based on Matlab/Simulink and able to use 3-dimensional field maps from either Finite Elements Method (FEM) solvers, such as Comsol, OPERA 3D or CST particle studio, fields calculated by the code itself, or field maps from measurements. This contribution describes the code structure and presents its performance limitations. It also gives a summary of results obtained from beam dynamics simulations of cyclotrons injection systems, storage ring extraction systems, electrostatic and magnetic beamlines, as well as from photocathode optimization studies.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME029

Export •

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

MOPME033

Beam Dynamics in an Electron Lens with the Warp Particle-in-cell Code

simulation, collider, gun, solenoid

451

G. Stancari
Fermilab, Batavia, Illinois, USA
V. Moens
EPFL, Lausanne, Switzerland
S. Redaelli
CERN, Geneva, Switzerland

Funding: Fermi Research Alliance, LLC operates Fermilab under Contract DE-AC02-07CH11359 with the US Department of Energy. Research supported in part by US LARP and EU FP7 HiLumi LHC, Grant Agreement 284404.
Electron lenses are a mature technique for beam manipulation in colliders and storage rings. In an electron lens, a pulsed, magnetically confined electron beam with a given current-density profile interacts with the circulating beam to obtain the desired effect. Electron lenses were used in the Fermilab Tevatron collider for beam-beam compensation, for abort-gap clearing, and for halo scraping. They will be used in RHIC at BNL for head-on beam-beam compensation, and their application to the Large Hadron Collider for halo control is under development. At Fermilab, electron lenses will be implemented as lattice elements for nonlinear integrable optics. The design of electron lenses requires tools to calculate the kicks and wakefields experienced by the circulating beam. We use the Warp particle-in-cell code to study generation, transport, and evolution of the electron beam. For the first time, a fully 3-dimensional code is used for this purpose.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME033

Export •

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

MOPME043

Modeling and Simulation of Beam-induced Plasma in Muon Cooling Devices

plasma, simulation, cavity, ion

466

K. Yu
SBU, Stony Brook, USA
M. Chung, A.V. Tollestrup, K. Yonehara
Fermilab, Batavia, Illinois, USA
B.T. Freemire
IIT, Chicago, Illinois, USA
V. Samulyak
BNL, Upton, Long Island, New York, USA
V. Samulyak
SUNY SB, Stony Brook, New York, USA

Understanding of the interaction of muon beams with plasma in muon cooling devices is important for the optimization of the muon cooling process. We have developed numerical algorithms and parallel software for self-consistent simulation of the plasma production and its interaction with particle beams and external fields. Simulations support the experimental program on the hydrogen gas filled RF cavities in the Mucool Test Area (MTA) at Fermilab. Computational algorithms are based on the electromagnetic particle-in-cell (PIC) code SPACE combined with a probabilistic, macroparticle-based implementation of atomic physics processes such as the absorption of the incident particles, ionization of the absorber material, and the generation and evolution of secondary particles in dense, neutral gas. In particular, we have proposed a novel algorithm for dealing with repetitive incident beam, enabling simulations of long time scale processes. Benchmarks and simulations of the experiments on gas-filled RF cavities and prediction for future experiments are discussed.
* kwangmin.yu@stonybrook.edu
** rosamu@bnl.gov

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME043

Export •

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

MOPME044

Upgrade of the Machine Interlock System for the ELBE Accelerator Facility

PLC, vacuum, controls, status

469

M. Justus, M. Freitag, B. Lange, P. Michel, W. Sorge, R. Steinbrück, H. Tietze
HZDR, Dresden, Germany

The ELBE facility with its 40 MeV C.W. LINAC has recently received an upgrade in terms of new secondary radiation sources and beam lines, while advancing the accelerator infrastructure towards 1.6 mA C.W. operation (1.0 mA before). Therefore, the machine interlock system (MIS) was redesigned in parts to meet the new timing requirements resulting from the increased overall beam power. It comprises fast beam loss detection and a PLC based beam line equipment protection system (EPS), both tripping the key components of the electron sources. The former tripping system using PLC interrupts was replaced by an in-house developed staggered CPLD based system with optical transmission and a PROFINET IO interface for control system integration. The EPS is distributed on several PLCs and has been improved in terms of M2M communication. Further, the vacuum inrush protection was completely renewed using brought-in equipment. This contribution depicts the technical features and performance of the MIS subsystems, as well as the actual status within the upgrade project.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME044

Export •

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

MOPME051

Turbo Generators for Powering the HV-solenoids at the HESR Electron Cooler

solenoid, high-voltage, power-supply, acceleration

492

A. Hofmann, K. Aulenbacher, M.W. Bruker, J. Dietrich, T. Weilbach
HIM, Mainz, Germany
M.I. Bryzgunov, A.P. Denisov, V.M. Panasyuk, V.V. Parkhomchuk, V.B. Reva
BINP SB RAS, Novosibirsk, Russia

New experiments at the planned 'High Energy Storage Ring' (HESR) require magnetised electron cooling. One of the challenges is the powering of the HV-solenoids, because they are located on HV-sections, which sit on an electrical potential inside a high voltage vessel. We discuss a Multi-MV system where the solenoids are powered by a series of cascade transformers which are in turn supplied by turbogenerators. The usage of SF6 as turbine fluid is desirable from the viewpoint of operational stability and may also lead to energy efficient operation of the turboexpanders since a Organic Rankine-cycle (so-called ORC-process) may be used instead of electrically driven compressors. The paper gives an overview of the turbo generator and ORC project: an introduction, a status report and a road map will be given.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME051

Export •

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

MOPME067

Kicker Development at the ELBE Facility

kicker, positron, gun, SRF

520

G.S. Staats
FZD, Dresden, Germany
A. Arnold, H. Büttig, T. Kirschke, M. Kuntzsch, P. Michel, J. Teichert, H. Vennekate, A. Wagner, R. Xiang
HZDR, Dresden, Germany
R. Krause-Rehberg, A. Müller
Martin-Luther-Universität, Naturwissenschaftliche Fakultät II, Halle (Saale), Germany

Kicker-devices, also known as choppers, are of great interest for a multi-purpose electron accelerator like the ELBE at HZDR. They serve the following three main tasks: Firstly, they can be used to improve the time resolution for the positron beam line by removing certain parts of the bunch. As a second advantage they enable the machine to run two independent experiments at the same, as a chopper may split the beam into two separate parts. Lastly, a well-positioned kicker can reduce the dark current emitted by the SRF injector of the accelerator. Different designs for structures, deflecting the bunch in the beam line, have been simulated using CST Particle Studio. Here, no big difference to well-known strip line structures do exist. The next step is to design the supply electronics driving the kickers. As the ELBE accelerator runs at a high bunch repetition rate, the kicker has to keep up to this frequencies of up to 13 MHz. Hence, the high power levels needed for the operation may cause additional problems for the driver electronics. The poster is going to present the state of our development for all three tasks and our approaches to solve the corresponding challenges.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME067

Export •

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

MOPME073

Status of Injection Complex VEPP-5: Machine Commissioning and First Experience of Positron Storage

injection, positron, dumping, damping

538

A.A. Starostenko, F.A. Emanov, E.S. Kazantseva, P.V. Logatchov
BINP SB RAS, Novosibirsk, Russia

The Injection complex VEPP-5 consist of S-band linear accelerators (270 and 420 MeV), positron convertor (at 270 MeV) and damping ring. The injection complex is in commission. Positron rate production about 6·10⁸ positrons/pulse and conversion yield 0.14/GeV was achieved. Storage ring positron beam current is 70mA was achieved.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME073

Export •

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

MOPRI002

Design, Manufacture and Operation of the Beam Spoiler for Positron Target Protection

target, positron, alignment, linac

573

L. Zang, K. Kakihara, T. Kamitani, K. Mikawa, F. Miyahara, T. Suwada
KEK, Ibaraki, Japan

In order to produce positrons, intensive pulsed electron beam is used to strike on a tungsten target. The energy deposition is distributed non-uniformly over the target, leading to a mechanical stress. As a result of large thermal gradient, the target could be potentially damaged. To avoid the target destruction, the peak energy deposition density (PEDD) in the target should be well below the critical limit (35J/g) based on the SLAC operational experience. With an expected primary electron spot size on the target of the SuperKEKB positron source, the PEDD will exceeds the limit. We will introduce a beam spoiler to enlarge the spot size by multiple scattering in thin beam screen and aluminum plate. It reduces the PEDD down to half of the limit. This paper describes the design of the spoiler and the beam screen system used in the positron beam commissioning of the SuperKEKB positron source started in 2014.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI002

Export •

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

MOPRI003

Positron Yield Optimization by Adjusting the Components Offset and Orientation

positron, target, injection, simulation

576

L. Zang, M. Akemoto, S. Fukuda, K. Furukawa, T. Higo, N. Iida, K. Kakihara, T. Kamitani, T. Miura, F. Miyahara, Y. Ogawa, H. Someya, T. Takatomi, K. Yokoyama
KEK, Ibaraki, Japan
S. Ushimoto
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan

In order to keep high luminosity beam collision condition at SuperKEKB, low emittance electron/positron injection and flexible pulse-to-pulse switching of these beam modes are essential requirements. While a primary electron beam strikes on a target to generate positrons, an injection electron beam passes through a small hole besides the target. Since the injection electron orbit should be on axis to avoid emittance growth, the target and the flux concentrator for positron focusing have a few millimeters offset from the axis. This offset positron generation gives significant degradation in the positron yield. In this paper, we will discuss positron yield improvement by proper orientation of the cut-in slit of the flux concentrator which yields un-symmetric field distribution and primary electron incident point. With particle tracking simulation taking three dimensional field distribution into account, an ideal positron trajectory giving optimum yield was found.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI003

Export •

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

MOPRI004

SuperKEKB Positron Source Construction Status

positron, target, solenoid, operation

579

T. Kamitani, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, Y. Funakoshi, K. Furukawa, T. Higo, H. Honma, N. Iida, M. Ikeda, E. Kadokura, H. Kaji, K. Kakihara, H. Katagiri, M. Kikuchi, H. Koiso, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Mimashi, T. Miura, F. Miyahara, T. Mori, A. Morita, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, Y. Ohnishi, S. Ohsawa, M. Sato, T. Shidara, A. Shirakawa, M. Suetake, H. Sugimoto, T. Suwada, T. Takatomi, T. Takenaka, M. Tanaka, M. Tawada, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou
KEK, Ibaraki, Japan
D. Satoh
TIT, Tokyo, Japan

The KEKB positron source is under the upgrade for SuperKEKB. The previous positron production target and capture section have been removed and the new system is constructed at a location forty meters upstream to have sufficient energy margin for beam injection to the newly introduced damping ring. A flux concentrator is introduced in the new capture section to make an adiabatic matching system. Large aperture (30mm in diameter) S-band accelerating structures are introduced in the capture section and in the subsequent accelerator module to enlarge the transverse phase space acceptance. The beam focusing system of quadrupoles is also upgraded for a comparable beam acceptance to that of the capture section. This paper reports on the status of the SuperKEKB positron source construction and the preliminary positron beam commissioning.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI004

Export •

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

MOPRI005

The AWAKE Experimental Facility at CERN

proton, plasma, laser, experiment

582

E. Gschwendtner, T. Bohl, C. Bracco, A.C. Butterworth, S. Cipiccia, S. Döbert, V. Fedosseev, E. Feldbaumer, C. Heßler, W. Höfle, M. Martyanov, M. Meddahi, J.A. Osborne, A. Pardons, A.V. Petrenko, H. Vincke
CERN, Geneva, Switzerland

AWAKE, an Advanced Wakefield Experiment is launched at CERN to verify the proton driven plasma wakefield acceleration concept. Proton bunches at 400 GeV/c will be extracted from the CERN SPS and sent along a 750m long proton line to the plasma cell, a Rubidium vapour source, where the proton beam drives wakefields reaching accelerating gradients at the order of gigavolt per meter. A high power laser pulse will co-propagate within the proton bunch creating the plasma by ionizing the (initially) neutral gas. An electron beam will be injected into the plasma cell to probe the accelerating wakefield. The AWAKE experiment will be installed in the CNGS facility. First proton beam to the plasma cell is expected by end 2016. The design of the experimental area and the integration of the new beam-lines as well as the experimental equipment will be shown. The needed modifications of the infrastructure in the facility will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI005

Export •

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

MOPRI006

Possible Uses of Gamma-rays at Future Intense Positron Sources

undulator, positron, synchrotron, software

586

A.O. Alrashdi, I.R. Bailey
Lancaster University, Lancaster, United Kingdom
A.O. Alrashdi, I.R. Bailey, D. Newton
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A.O. Alrashdi
KACST, Riyadh, Kingdom of Saudi Arabia
D. Newton
The University of Liverpool, Liverpool, United Kingdom

Funding: This research is funded in part by STFC grant ST/G008248/1
The baseline design of the ILC (International Linear Collider) positron source requires the production of an intense flux of gamma rays. In this paper we present an investigation of using the gamma ray beam of the ILC for additional applications, including nuclear physics. As a result of changing the collimator shape, as well as the parameters of the undulator magnets, we obtained spectra from numerical simulations using the HUSR/GSR software package. We present results from simulations and a discussion of possible future investigations in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI006

Export •

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

MOPRI011

Control of Plasma Flux with Pulsed Solenoid for Laser Ion Source

ion, plasma, ion-source, laser

601

S. Ikeda, K. Horioka
TIT, Yokohama, Japan
Y. Fuwa, S. Ikeda, M. Kumaki
RIKEN, Saitama, Japan
T. Kanesue, M. Okamura
BNL, Upton, Long Island, New York, USA

We discuss the behavior of laser-ablation plasma spreading through a pulsed solenoidal field to minimize the beam emittance of laser-ablation ion source (LIS). LIS is expected to produce high-flux and low emittance ion beams from various solid materials in vacuum because of the high drift velocity and low temperature of the ablation plasma due to the adiabatic expansion. However, the ion flux level from the ablation plasma into an extraction gap changes within a pulse and then the shape of the sheath boundary changes transiently. Then, the integrated emittance is larger than the stroboscopic emittance at a certain time slice. To prevent the transient effect, we tried to control the plasma flux with a pulsed solenoidal magnetic field. The field is expected to change the direction of the plasma flow like a lens. By changing the magnetic flux density according to the transient flux level of ablation plasma, we can expect to control the plasma flux at the extraction gap. To investigate the controllability of the plasma flow, we measured the plasma flux as a function of parameters of the pulsed magnetic field. We scanned ion probes along the beam.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI011

Export •

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

MOPRI017

Status of AREAL RF Photogun Test Facility

gun, laser, operation, emittance

620

B. Grigoryan, G.A. Amatuni, V.S. Avagyan, H. Avdishyan, H. Davtyan, A.A. Gevorgyan, L.H. Hakobyan, M. Ivanyan, V.G. Khachatryan, E.M. Laziev, A. Lorsabyan, M. Manukyan, I.N. Margaryan, N. Martirosyan, T.H. Mkrtchyan, S. Naghdalyan, V.H. Petrosyan, H. Poladyan, V. Sahakyan, A. Sargsyan, A.V. Tsakanian, V.M. Tsakanov, A. Vardanyan, V. V. Vardanyan, G.S. Zanyan
CANDLE SRI, Yerevan, Armenia
T.K. Sargsyan
LT-PYRKAL cjsc, Yerevan, Armenia

Advanced Research Electron Accelerator Laboratory (AREAL) is a 20 MeV laser driven RF linear accelerator which is being constructed in the CANDLE institute. The construction of phase-1 is finished and at present the machine commissioning is in progress. In phase-1 a photocathode RF gun provides a 5 MeV small emittance electron beam with the 100 pC bunch charge and variable electron bunch length from 0.5 to 8 ps. Two main operation modes are foreseen for this phase – single and multibunch regimes to satisfy experimental demands. We report the status of linac, first experience and nearest machine run schedule. The brief review of the facility, main parameters, performance and first results are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI017

Export •

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

MOPRI019

In-situ Characterization of K2CsSb Photocathodes

cathode, laser, vacuum, ion

627

M. Schmeißer, A. Jankowiak, T. Kamps, S.G. Schubert
HZB, Berlin, Germany
S.G. Schubert
BNL, Upton, Long Island, New York, USA

Funding: Work supported by German Bundesministerium für Bildung und Forschung contract 05K12CB2 PCHB and Land Berlin.
Alkali antimonide photocathodes with high quantum efficiency hold the promise of delivering electrons for high-brightness injectors. A drift type spectrometer (momentatron) was attached to the HZB preparation system to allow in-situ characterization within short time after fabrication and possibly identify correlations between growth process and cathode performance parameters.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI019

Export •

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

MOPRI020

Introducing GunLab – A Compact Test Facility for SRF Photoinjectors

gun, SRF, laser, cathode

630

J. Völker, R. Barday, A. Jankowiak, T. Kamps, J. Rudolph, S.G. Schubert, S. Wesch
HZB, Berlin, Germany
A. Ferrarotto, T. Weis
DELTA, Dortmund, Germany
V.I. Shvedunov
MSU, Moscow, Russia
I.Yu. Vladimirov
MSU SINP, Moscow, Russia

Funding: Work supported by German Bundesministerium für Bildung und Forschung (BMBF contract 05K12CB2 PCHB and 05K10PEA), Land Berlin and grants of Helmholtz Association
Superconducting radio-frequency photoelectron injectors (SRF photoinjectors) are a promising electron source for high brightness accelerators with high average current and short pulse duration like FELs and ERLs. For the upcoming ERL project BERLinPro we want to test and commission different SRF photoinjectors and examine the beam performance of photocathode materials in an independent test facility. Therefore we designed GunLab to characterize the beam parameters from the SRF photoinjectors in a compact diagnostics beamline. In GunLab we want to investigate the complete 6 dimensional phase space as a function of drive laser and RF setup parameters. In this work we present the design and the estimated performance of GunLab.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI020

Export •

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

MOPRI021

Laser Systems Generating Short Polarized Electron Bunches at the S-DALINAC

laser, operation, experiment, cathode

633

M. Espig, J. Enders, Y. Fritzsche, A. Kaiser, M. Wagner
TU Darmstadt, Darmstadt, Germany

Funding: Supported by DFG within CRC634 and by the state of Hesse through the LOEWE center HIC for FAIR.
The source of polarized electrons at the superconducting Darmstadt electron linear accelerator S-DALINAC uses photo-emission from strained-layer superlattice-GaAs and bulk-GaAs photocathodes. This system is driven by either 3 GHz gain-switched diode lasers or a short-pulse Ti:Sapphire laser system. Highly polarized electrons are generated with laser light at 780 nm, while blue laser light is used for unpolarized high-current experiments. We present the existing pulsed laser systems and the planned developments for the diode laser system, including, e.g., impedance matching of the diode lasers, gain switching with short electrical pulses and pulsing with a Mach-Zehnder modulator. The pulsed operation is aimed at generating short electron bunches (< 50 ps) at the S-DALINAC with variable repetition rates from some MHz to 3 GHz.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI021

Export •

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

MOPRI026

Complete Simulation of Laser Induced Field Emission from Nanostructures Using a DGTD, PIC and FEM Code

laser, simulation, cathode, space-charge

645

A. Fallahi, F.X. Kärtner
CFEL, Hamburg, Germany
K.K. Berggren, R. Hobbs, F.X. Kärtner, P.D. Keathley, M.E. Swanwick, L.F. Velasquez-Garcia, Y. Yang
MIT, Cambridge, Massachusetts, USA

Funding: DARPA contract number N66001-11-1-4192 and the Center for Free-Electron Laser Science, DESY Hamburg.
We present a general and efficient numerical algorithm for studying laser induced field emission from nanostructures. The method combines the Discontinuous Galerkin Time Domain (DGTD) method for solving the optical field profile, the Particle-In-Cell (PIC) method for capturing the electron dynamics and the Finite Element Method (FEM) for solving the static field distribution. The charge distribution is introduced to the time-domain method based on a modified Fowler-Nordheim field emission model, which accounts for the band-bending of the charge carriers at the emitter surface. This algorithm is capable of considering various effects in the emission process such as space-charge, Coulomb blockade and image charge. Simulation results are compared with experimental findings for optically driven electron emission from nanosharp Si-tips.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI026

Export •

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

MOPRI027

Dark Current Studies at Relativistic Electron Gun for Atomic Exploration – REGAE

gun, cavity, vacuum, operation

649

H. Delsim-Hashemi, K. Flöttmann
DESY, Hamburg, Germany

Electron diffraction is a tool for exploring structural dynamics of matter. The scattering cross section is orders of magnitude higher for electrons than for X-rays so that only a small number of electrons is required to achieve comparable results. However, the required electron beam quality is extraordinary. To study e. g. proteins a coherence length of 30 nm is required which translates into a transverse emittance of 5 nm at a spot size of 0.4mm. In addition short bunch lengths down to 10 fs and a temporal stability of the same order are required in order to study chemical reactions or phase transitions in pump probe type experiments. These are challenging parameters for an electron source, which demand improvements at many frontiers. Dark current degrades contrast of diffraction patterns in all experiments. Understanding dark-current generation and propagation can lead to better methods to decrease it. In this paper dark current studies that are performed at REGAE will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI027

Export •

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

MOPRI028

Different Countermeasures of Electron Amplification in the Photocathode Unit

cathode, SRF, gun, simulation

652

E.T. Tulu, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
A. Arnold
HZDR, Dresden, Germany

Funding: Federal Ministry for Research and Education BMBF; Project: 05K2013-HOPE
Superconducting radio frequency (SRF) structures may be subjected to electron multipacting (MP). The electrons emitted from one of the structure’s wall under certain conditions are accelerated by the RF field, thereby they may impact the wall again based on the field pattern in the structure. Accordingly the number of electrons increases exponentially caused by secondary electron emission*. The latter depends on the secondary emission coefficient of the surface material and the electron trajectory in the device under study**. This phenomenon limits the accelerating gradient in the cavity, moreover, it might cause an impair of RF components and distortion of the RF signal. Therefore, there should be an efficient countermeasure to suppress MP in order to boost the performance of the SRF gun. In this paper, three techniques of suppression of MP from the vicinity of the cathode, such as DC-bias, geometric modification and the microstructure of the cathode's surface, in the Rossendorf SRF gun are presented. The simulation has been done using CST Microwave Studio® and CST Particle Studio®***. Eventually, the efficient suppression method would be chosen for this particular case.
* H.Padamsee, J. Knobloch and T. Hays, 1998, Ch. 10.
** E. T. Tulu, A. Arnold and U. van Rienen, 16th International Conference on SRF, Paris, France, 2013.
*** CST AG, http://www.cst.com.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI028

Export •

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

MOPRI029

Spectrometer for Laser-pulsed Electrons from Field Emission Cathodes

cathode, laser, detector, controls

655

S. Mingels, B. Bornmann, D. Lützenkirchen-Hecht, G. Müller, V. Porshyn
Bergische Universität Wuppertal, Wuppertal, Germany

Funding: German Federal Ministry of Education and Research (BMBF). Project number: 05K13PX2.
In order to develop highly brilliant, pulsed electron sources based on photo-induced field emission (PFE), which combines advantages of photo and field emission (FE), a new measurement system was constructed at BUW*. In an UHV system the electrons are extracted from a cold cathode by a mesh electrode under pulsed laser illumination (3.5 ns, 10 Hz, 0.5 – 5.9 eV, > 0.3 mJ) and so far analyzed by a CW-spectrometer. Quantum efficiency investigations of flat metal (Au, Ag of different surface orientations) and semiconductor crystals (n- and p-Si**, GaN) yielded the expected work functions and revealed first hints for PFE effects. However, the kinetic energy of the electrons could not be measured with the CW-spectrometer. In addition, the achievable electric field (< 20 MV/m) was limited by parasitic FE. Hence, the system is presently upgraded with a spectrometer (resolution < 3 meV) that can handle electron pulses and a dust reduced environment is installed at the load lock. First results acquired with the upgraded apparatus on PFE cathodes will be presented at the conference.
* B. Bornmann et al., Rev. Sci. Instrum. 83, 013302 (2012).
** S. Mingels et al., Proc. FEL2013, New York, USA, p. 339.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI029

Export •

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

MOPRI030

Basic Design of a 20K C-band 2.6-cell Photocathode RF Gun

cavity, gun, simulation, vacuum

658

T. Tanaka, M. Inagaki, K. Nakao, K. Nogami, T. Sakai
LEBRA, Funabashi, Japan
M.K. Fukuda, T. Takatomi, J. Urakawa, M. Yoshida
KEK, Ibaraki, Japan
T.S. Shintomi
Nihon University, Tokyo, Japan

Funding: This research was supported by the Photon and Quantum Basic Research Coordinated Development Program of the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT).
A cryocooled C-band photocathode RF gun operating at 20K is under design at Nihon University. The RF gun is of BNL-type 2.6-cell pillbox cavity with a resonant frequency of 5712 MHz. With high-purity Oxygen-free copper used as the cavity material, the quality factor of the cavity is expected to be approximately 60000 from theoretical prediction of the anomalous skin effect at low temperatures. Considering the cooling capacity, initial operation of the RF gun is assumed at a duty factor of 0.01%. The cavity elements designed for low-power test is in preparation for machining. The low-power test at room temperature is scheduled early spring in 2014 before assembled at KEK by means of diffusion bonding technique. Since it is intended for the basic understanding and measurements of low temperature RF properties, the cavity is not equipped with structures for the photocathode assembling or the RF input coupler. The cavity design and the results of RF properties measured at room temperature before diffusion bonding will be reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI030

Export •

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

MOPRI031

Multi-alkali Photocathode R&D

cathode, laser, vacuum, experiment

661

Y. Seimiya, M. Kuriki, N. Yamamoto
HU/AdSM, Higashi-Hiroshima, Japan

Multi-alkali photocathode has excellent features: high quantum efficiency, long lifetime, and excitation by visible light, for example green laser. The multi-alkali cathode is considered to be one of the best candidate of the high brightness electron source of the advanced electron accelerator such as ERL and FEL. We study conditions of multi-alkali evaporations, such as thicknesses, substrate temperature, and evaporation rate, and examine the cathode performances, such as quantum efficiency and extractable current density. Antimony (Sb), potassium (K), and cesium (Cs) are used in our evaporation system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI031

Export •

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

MOPRI032

A STUDY ON ROBUSTNESS OF NEA-GAAS PHOTOCATHODE*

cathode, vacuum, experiment, emittance

664

K. Uchida, R. Kaku, M. Kuriki, K. Miyoshi, Y. Seimiya, N. Yamamoto
HU/AdSM, Higashi-Hiroshima, Japan
H. Iijima
Tokyo University of Science, Tokyo, Japan

Electron source is one of the most important component in the advanced linac. There is a strong demand on the high performance cathode, such as small emittance, high brightness, and short pulse generation. NEA-GaAs photo-cathode is a unique technology which is capable for generating highly polarized and extremely low emittance beam. Quantum efficiency (QE) of the cathode is high in near IR region, so it is favor to generate a high current density beam. These advantages are originated to the Negative Electron Affinity (NEA) surface, but it is fragile so the operational lifetime is limited. A study on a robust NEA surface cathode is reported. According to the hetero-junction model, Cs-Te thin film deposited on GaAs forms a robust NEA surface. We performed the Cs-Te evaporation experiment on a clean GaAs cathode and measured QE spectra. We found that some sample showed a high quantum efficiency up to 900nm wavelength which strongly suggested a NEA surface formation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI032

Export •

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

MOPRI034

Development of temporal response measurement system for transmission-type spin-polarized photocathodes

cavity, laser, resonance, linear-collider

670

T. Inagaki, M. Hosaka, Y. Takashima, N. Yamamoto
Nagoya University, Nagoya, Japan
M. Adachi
KEK, Ibaraki, Japan
X.G. Jin
Institute for Advanced Research, Nagoya, Japan
M. Katoh, T. Konomi
UVSOR, Okazaki, Japan
Y. Okano
IMS, Okazaki, Japan

Spin polarized electron beam is essential for "International Linear Collider". In Nagoya University, transmission-type spin-polarized photocathodes have been developed, and the quantum efficiency of 0.5 % and the polarization of 90 % were achieved*,**. Recently, we succeeded in making the active layer several times thicker with keeping the spin polarization on the GaAs/GaAsP strain-compensated superlattice photocathode***. Increasing the thickness of the active layer is very advantageous for high quantum efficiency, but might be disadvantageous for pulse response. In order to investigate the pulse response, we have developed a pulse length measurement system by using an RF deflecting cavity. In the measurement, magnetic field induced on the beam axis kicks electron pulse transversely and the pulse length is projected to the transverse plane, which is measured by knife-edge method. The pump laser pulses are provided by a Ti:sapphire laser oscillator. By using a pulse stretcher, the pulse width of the pump laser can be changed in the range between 130 fs and 20 ps. In the poster session, we will describe the details of the measurement system and the most recent experimental results.
* T. Nakanishi, The XXI International LINAC Conference(1998)
** Xiuguang Jin, Japanese Journal of Applied Physics 51 (2012) 108004
*** Xiuguang Jin, Applied Physics Express 6 (2013) 015801

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI034

Export •

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

MOPRI035

Development of the Photocathode LiTi2O4 and Evaluations of the Initial Emittance

cathode, laser, emittance, cavity

673

R. Inagaki, M. Hosaka, Y. Takashima, N. Yamamoto
Nagoya University, Nagoya, Japan
T. Hitosugi, S. Shiraki
Tohoku Uneversity, WPI-AIMR, Sendai, Japan
E. Kako, Y. Kobayashi, S. Yamaguchi
KEK, Ibaraki, Japan
M. Katoh, T. Konomi, T. Tokushi
UVSOR, Okazaki, Japan
Y. Okano
IMS, Okazaki, Japan

In UVSOR, the X-ray free electron laser (XFEL) based on linear accelerator with high pulse repetition about 1MHz has been designed as a candidate for the next radiation sources. We thought a combination of superconducting RF cavity and photocathode is an optimal electron gun for the new accelerator. For this electron gun, we propose a back-illuminated multi-alkali* photocathode with transparent superconductor LiTi2O4**. The reason for using LiTi2O4 is to reflect RF by using feature of penetration depth of superconductor, which is defined from London equation. This feature protects optical components from RF damage. However, LiTi2O4 is a new material and properties are not clear. We have measured the basic properties of this photocathode, such as magnetic susceptibility measurement and photoelectron spectrometry, etc. In this conference, we will explain the detail of the concept and advantage of this cathode, and show the result measured about the basic properties of this photocathode focusing on the initial emittance measurement.
* A. V. Lyashenko et al. JINST 4 P07005 (2009)
** Kumatani et al. APL 101 (2012) 123103″

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI035

Export •

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

MOPRI036

Pulse Radiolysis Using Terahertz Probe Pulses

laser, radiation, gun, linac

676

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

Pulse radiolysis, which utilizes a pump electron beam and a probe pulse, is a powerful tool that can be used for the time-resolved observation of ultrafast radiation-induced phenomena. Recently, double-decker pulse radiolysis* using visible probe pulses were demonstrated based on a photocathode RF gun driven by two UV pulses, which enabled synchronized pump electron beam and visible probe pulses. In this study, pulse radiolysis using terahertz (THz) probe pulses which were realized by the “double-decker” electron beams and dynamics of transient quasi-free electrons in semiconductors are presented.
* K. Kan et al., Rev. Sci. Instrum. 83, 073302 (2012).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI036

Export •

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

MOPRI037

Development of Iridium Cerium Photocathode for the Generation of High-Charge Electron Beam

laser, cathode, gun, linac

679

D. Satoh
TIT, Tokyo, Japan
N. Hayashizaki
RLNR, Tokyo, Japan
T. Natsui, M. Yoshida
KEK, Ibaraki, Japan

We developed an iridium cerium cathode material made by new production method for multi-purpose electron source. For multi-purpose electron source, we focused on the Ir5Ce compound which has a high melting point (> 2100 K) and a low work function (2.57 eV). This material has some excellent properties as both a thermionic cathode and a photocathode. For example, Ir5Ce thermionic cathode can generate one-order higher electrical current than a LaB6 cathode at the same temperature. Another advantage is that an Ir5Ce thermionic cathode has a lifetime two orders longer than that of a LaB6 thermionic cathode under the same conditions. Moreover, we discovered that this material has a reasonably high quantum efficiency (2.70 × 10−3 @213nm at 1000°C) and long-lifetime (> LaB6) as a photocathode. Our research shows that Ir5Ce compound is optimum material for a thermionic cathode and photocathode. We focused on this good emission properties under the high temperature and we tried to develop a backside electron beam heating system and demonstrate a laser pre-pulse heating for a high current thermionic gun system or high charge photocathode gun.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI037

Export •

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

MOPRI038

Study on Quantum Efficiency of NEA-GaAs with Various Thermal Treatments; The Increase in Quantum Efficiency by the Low Temperature Treatment.

ion, site, experiment, vacuum

682

K. Hayase, R. Chiba, H. Iijima, Y. Inagaki, T. Meguro
Tokyo University of Science, Tokyo, Japan

Negative electron affinity (NEA) surface are formed by deposition of Cs atoms on p-GaAs, and the drastic increase in the electron emission is observed by the Yo-Yo method. It is necessary to remove oxide layers of GaAs surface for the NEA surface formation, therefore the thermal treatment was carried out prior to the NEA activation. We have discussed the quantum efficiency (QE) with different thermal history. GaAs surfaces cleaned with organic solvents were thermally treated with the temperature sequence of 773K, 823K, and 723K. The NEA activation was carried out at every temperature. The QE less than 1% was obtained with 773K of treatment temperature on the initial surface. Then the QE increased at 10% after treatment at higher 823K. Successive increase of the QE to 13% was observed with a reduced temperature treatment at 723K. The GaAs surfaces after the thermal treatment in the high temperature region with the NEA activation are different from the as-cleaned-GaAs surfaces probably in stoichiometry or morphology due to desorption of As and Ga atoms. The role of thermal treatment with NEA activation is the modification of surface properties important for elevating the QE.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI038

Export •

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

MOPRI039

Ultra-short Electron Bunch Generation using Energy-chirping Cell Attached RF Electron Gun

gun, cavity, simulation, radiation

685

K. Sakaue, Y. Koshiba, M. Mizugaki, M. Washio
Waseda University, Tokyo, Japan
R. Kuroda
AIST, Tsukuba, Ibaraki, Japan
T. Takatomi, J. Urakawa
KEK, Ibaraki, Japan

Funding: Work supported by JSPS Grant-in-Aid for Young Scientists (B) 23740203 and Scientific Research (A) 10001690
We have been developing an Energy-Chirping-Cell attached RF electron gun (ECC-RF-Gun) for generating ultra-short electron bunches. ECC-RF-Gun has extra cell at the end of gun cavity in order to chirp the bunch energy. Such a bunch can be compressed by the velocity difference though the drift space. We have already installed it to our accelerator system and successfully observed a coherent synchrotron/transition radiation at 0.3THz. It is clear that the bunch length was short enough to generate 0.3THz, which corresponds to less than 500fs bunch length was achieved if we assume the gaussian shape. In this conference, the principle of ECC-RF-Gun, the recent results of bunch length measurement and future prospective will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI039

Export •

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

MOPRI040

Design and Analysis of an Electron Beam in an Electron Gun for X-Ray Radiotherapy

gun, cathode, emittance, simulation

688

J.C. Lee, J.-S. Chai, M. Ghergherehchi, H.S. Kim, Y.S. Lee, S. Shin, Y.H. Yeon
SKKU, Suwon, Republic of Korea
B.N. Lee
KAERI, Dae-jeon, Republic of Korea

Funding: This work was supported by (IT R&D program of MSIP/KEIT [10043897] and MOTIE [13-DU-EE-12]) in KOREA.
Electron linear accelerators are used as x-ray generators for diagnosing the human body. In this paper conceptual design of electron beam for compact electron gun was calculated by using EGN2w and CST-Particle Studio codes. The structure of the electron gun was used for Pierce and diode type and the specification of electron beam was selected as 500 cGy/min. Specifications of designed electron gun were focused on current, beam size and normalized emittance. Optimized beam current, diameter and normalized emittance are 226.88 mA, 0.689 mm (Full width) and 1.03π mm• mrad, respectively by using two simulation codes. Accuracy of simulation was verified by comparison of emitted beam current which has error of 0.74%.
* Subhash C. Sharma et al., Journal of applied clinical medical physics, 8, 3 (2007) 119-125.
* Yuichiro Kamino et al., Med. Phys. 34 (2007) 1797-1808.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI040

Export •

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

MOPRI041

Electrons Injectors with Cathode Diameter of 6/15mm and New Cup Energy Input on the Wave E11 for Accelerators

cathode, Windows, gun, target

692

K.G. Simonov, E.A. Alkhimenko, T.A. Batkova, S.I. Grishin, A.V. Mamontov, G.I. Pravdikovskaya, E.A. Stroykov
ISTOK, Moscow Region, Russia
A.I. Shapovalov
MRTI RAS, Moscow, Russia

RPC "Istok" has created a number of electron injectors with voltage of 20-60kV and cathode diameter of 6-15mm of diode and triode designs. Injectors use the impregnated cathodes; the injector design allows rapid replacement of cathode assemblies. Injectors have been widely used in linear electron accelerators in Russia and Ukraine, in particular, in the sterilization accelerator center of JSC "MRTI RAS", Moscow, in the accelerator of the Russian Eye and Plastic Surgery Centre, Ufa. Have been proposed new input energy windows on the E11 wave, providing significant levels of transmission of the pulse power at high average power levels. Have been created two types of windows at 10-cm range, in which the ceramic disk made of ecologically clean alumina ceramic with diameter of 103mm and thickness of 13mm is used. In the first type of windows the heat transfer is provided from the peripheral portion, and in the second type of window – both from peripheral and central portions of the ceramic disk. These windows are used in accelerator of FSUE "NIIEFA" (St.Petersburg), installed at Izhora mill for testing the welding seals of atomic reactors and in accelerator of JSC "MRTI RAS".

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI041

Export •

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

MOPRI044

Feasibility Study of an Ultrafast Electron Diffraction System in NSRRC

gun, injection, cathode, emittance

701

P. Wang, K.C. Leou
NTHU, Hsinchu, Taiwan
N.Y. Huang, W.K. Lau, A.P. Lee
NSRRC, Hsinchu, Taiwan

It has been suggested that the MeV beam generated from a laser-driven photo-cathode rf gun can be used for ultrafast electron diffraction (UED)*. The feasibility of operating the NSRRC photo-cathode rf gun system for ultrashort bunch generation is being investigated. The results of space-charge tracking calculations show that a low emittance, few hundred femtoseconds MeV beam with reasonable bunch charge can be generated for single shot UED experiments. In this report, a preliminary design of this UED system will be discussed.
* X.J. Wang et al., in Proceedings of PAC'03, p.420.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI044

Export •

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

MOPRI045

Beam Diagnostics E-GUN Test Stand at TARLA

gun, emittance, radiation, cathode

704

Ç. Kaya, A.A. Aksoy, A. Aydin, V. Karakilic, Ö. Karslı, E. Kazancı, B. Koc, S. Kuday, E.Ç. Polat, I. Sara, M. Yildiz
Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
S. Özkorucuklu
Istanbul University, Istanbul, Turkey

Funding: Work supported by Turkish State Planning Organization (Grant No: DPT2006K-120470)
Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) facility, which is essentially proposed to generate oscillator mode FEL in 3-250 microns wavelengths range, will consist of totally normal conducting injector system with 250 keV beam energy, two superconducting RF accelerating modules in order to accelerate the beam 15-40 MeV. Continuous wave (CW) electron beam will provided by TARLA thermionic electron gun (E-GUN). Various aspects of the Thermionic EGUN test stand to deliver the necessary electron beam in terms of bunch charge, current, energy, emittance and profile for the beam diagnostic will be discussed. Primarily measurements results of electron beam energy loss and transverse orbit will be shown as well as beam image and shape measurements.
On behalf of TARLA Collaboration

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI045

Export •

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

MOPRI046

The Evolution of the Transverse Energy Distribution of Electrons from a GaAs Photocathode as a Function of its Degradation State

detector, cathode, laser, brightness

707

L.B. Jones, B.L. Militsyn, T.C.Q. Noakes
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
H.E. Scheibler, A.S. Terekhov
ISP, Novosibirsk, Russia

The brightness of a photoelectron injector is fundamentally limited by the mean longitudinal and transverse energy distributions of the photoelectrons emitted from its photocathode, and the electron beam brightness is increased significantly if the mean values of these quantities are reduced. ASTeC have commissioned a Transverse Energy Spread Spectrometer (TESS – an experimental facility designed to measure these transverse and longitudinal energy distributions) which can be used for III-V semiconductor, alkali antimonide/telluride and metal photocathode research*. GaAs photocathodes were activated in our photocathode preparation facility (PPF)**, then transferred to TESS under XHV conditions and progressively degraded through controlled exposure to oxygen. We present commissioning data and initial measurements showing the evolution of the transverse energy distribution of electrons from GaAs photocathodes as a function of their degradation state.
* Proc. FEL ’13, TUPPS033, 290-293
** Proc. IPAC ’11, THPC129, 3185-3187

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI046

Export •

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

MOPRI047

The Preparation of Atomically Clean Metal Surfaces for use as Photocathodes in Normally Conducting RF Guns

ion, gun, plasma, laser

711

T.C.Q. Noakes, A.N. Hannah, K.J. Middleman, B.L. Militsyn, R. Valizadeh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
S. Mistry
Loughborough University, Leicestershre, United Kingdom

Funding: Research supported by FP7 EuCard2 http://cern.ch/eucard2
This work reports a study of various alternative metal samples as candidate materials for use as photocathodes in normally conducting RF guns. Clean surfaces were prepared using Argon ion bombardment and quantum efficiency measured using a 265 nm UV LED light source with a picoammeter for drain current monitoring. Surface composition was studied using X-ray photoelectron spectroscopy and a Kelvin probe apparatus provided work function measurements. Data was taken both before and after annealing to 200°C, a temperature that is routinely achieved during RF gun vacuum baking. Ion bombardment typically leaves a very rough surface that can have a detrimental effect on beam emittance, so further work will focus on the use of Oxygen plasma cleaning of the best candidate alternative metals. An oxygen plasma treated Copper photocathode has been shown to produce an acceptable level of quantum efficiency in the VELA accelerator at Daresbury Laboratory.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI047

Export •

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

MOPRI049

An Ultracold Electron Facility in Manchester

laser, emittance, space-charge, extraction

714

Ö. Mete, R. Appleby, W. Bertsche, M.A. Harvey, G.X. Xia
UMAN, Manchester, United Kingdom
S. Chattopadhyay
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A.J. Murray
The University of Manchester, The Photon Science Institute, Manchester, United Kingdom

An ultra-cold atom based electron source (UCAE) facility has been built in the Photon Science Institute (PSI), University of Manchester. In this paper, the key components and working principles of this source are introduced. Pre-commissioning status of this facility and the preliminary simulations results are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI049

Export •

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

MOPRI050

Preliminary Study for an RF Photocathode based Electron Injector for AWAKE Project

emittance, laser, focusing, plasma

717

Ö. Mete, G.X. Xia
UMAN, Manchester, United Kingdom
G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
S. Chattopadhyay
Cockcroft Institute, Warrington, Cheshire, United Kingdom

AWAKE project, a proton driven plasma wakefield acceleration (PDPWA) experiment is approved by CERN. The PDPWA scheme consists of a seeding laser, a drive beam to establish the accelerating wakefields within the plasma cell; and a witness beam to be accelerated. The drive beam protons will be provided by the CERN's SPS. The plasma ionisation will be performed by a seeding laser and the drive beam protons to produce the accelerating wakefields. After establishing the wakefields, witness beam, namely, electron beam from a dedicated source should be injected into the plasma cell. The primary goal of this experiment is to demonstrate acceleration of a 5-15 MeV single bunch electron beam up to 1 GeV in a 10 m of plasma. This paper explores the possibility of an RF photocathode as the electron source for this PDPWA scheme based on the existing PHIN photoinjector at CERN. The modifications to the existing design, preliminary beam dynamics simulations in order to provide the required electron beam are presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI050

Export •

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

MOPRI051

Measurements of the Longitudinal Energy Distribution of Low Energy Electrons

cathode, laser, experiment, simulation

720

L.J. Devlin, O. Karamyshev, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
L.J. Devlin, O. Karamyshev, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
L.B. Jones, B.L. Militsyn, T.C.Q. Noakes
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: Work supported by STFC Cockcroft Core Grant No.ST/G008248/1
The Transverse Energy Spread Spectrometer (TESS) is an ASTeC experiment designed to measure the energy of electrons from different cathode materials. It is a dedicated test stand for future light sources. A full particle tracking code has been developed in the QUASAR Group, which simulates particle trajectories through TESS. Using this code it is possible to simulate different operational conditions of the experiment and cathode materials. The simulation results can then be benchmarked against experimental data to test the validity of the emission and beam transport model. Within this paper, results from simulation studies are presented and compared against experimental data as a collaboration within the Cockcroft Institute between ASTeC and the QUASAR Group for the case of measuring the longitudinal velocity distribution of electrons emitted from a gallium arsenide cathode using a grid structure as an energy filter.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI051

Export •

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

MOPRI053

High Repetition Rate Ultrafast Electron Diffraction at LBNL

emittance, gun, experiment, laser

724

D. Filippetto, M. Mellado Munoz, H.J. Qian, F. Sannibale, W. Wan, R.P. Wells, M.S. Zolotorev
LBNL, Berkeley, California, USA

Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231"
Here we propose to use the APEX photo-gun as novel source for time-resolved electron diffraction studies. The electron source has been designed, built and successfully tested at LBNL. It combines a high accelerating field needed for bright beams, MeV electron energy essential for time resolution in gas-phase experiments and studies of bulk processes, together with continuous (CW) operations. Ultra-short electron pulses can be delivered with a maximum repetition rate of 186 MHz, enabling new science to be studied. We report the design of a dedicated electron diffraction beamline that fits in the space constraints of the APEX tunnel. Simulations of beam properties have been carried out with a genetic optimizer, showing 100 fs time resolution. Beam jitters in energy, time and position are currently being characterized, and a mitigation strategy via fast feedback loops is discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI053

Export •

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

MOPRI055

APEX Present Experimental Results

cathode, gun, emittance, laser

730

D. Filippetto, C.W. Cork, S. De Santis, L.R. Doolittle, G. Huang, R. Huang, W.E. Norum, C. F. Papadopoulos, G.J. Portmann, H.J. Qian, F. Sannibale, J.W. Staples, R.P. Wells
LBNL, Berkeley, California, USA
J. Yang
TUB, Beijing, People's Republic of China

Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231
The APEX electron source at LBNL combines high-repetition-rate and high beam brightness typical of photo-guns, delivering low emittance electron pulses at MHz frequency. Proving the high beam quality of the beam is an essential step for the success of the experiment. It would enable high repetition rate operations for brightness-hungry applications such as X-Ray FELs, and MHz ultrafast electron diffraction. A full 6D characterization of the beam phase space at the gun beam energy (750 keV) is foreseen in the first phase of the project. Diagnostics for low and high current measurements have been installed and tested, measuring the performances of different cathode materials in a RF environment with mA average current. A double-slit system allows the characterization of beam emittance at high charge and full current (mA). An rf deflecting cavity and a high precision spectrometer allow the characterization of the longitudinal phase space. Here we present the latest results at low and high repetition rate, discussing the tools and techniques used.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI055

Export •

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

MOPRI057

Photoemission from III-V Semiconductor Cathodes

cathode, vacuum, photon, scattering

736

S.S. Karkare
Cornell University, Ithaca, New York, USA
I.V. Bazarov, L. Cultrera, W.J. Schaff
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
X.G. Jin
Institute for Advanced Research, Nagoya, Japan
Y. Takeda
Nagoya University, Nagoya, Japan

Quantum efficiencies (QE) and mean transverse energies (MTE) of GaAs photocathodes grown using various techniques: metal-organic vapor phase epitaxy (MOVPE), molecular beam epitaxy (MBE), and atomic polishing have been compared and found to be identical. GaAs and GaInP based samples grown at Nagoya University were activated and measured in the Cornell ERL photoinjector. These were found to be in agreement with the samples measured at the ERL injector in KEK.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI057

Export •

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

MOPRI058

Metal Plasmonic Nanostructures Functionalized by Atomic Layer Deposition of MgO for Photocathode Applications

cathode, vacuum, resonance, emittance

739

S.V. Baryshev, S.P. Antipov, A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA
M.R. Savina, A.V. Zinovev
ANL, Argonne, Illinois, USA
E. Thimsen
University of Minnesota, Minneapolis, USA

Funding: Euclid TechLabs LLC acknowledges support from the DOE SBIR program, grant No. DE-SC0009572.
To create high current, long lasting electron sources capable of providing sub-ps bunches, new photocathode concepts are sought. Most recently, plasmonic nanostructured metal surfaces or flat metal surfaces activated by an ultrathin MgO are under great attention. We report on a photocathode design combining these two approaches. It consists of plasmonic Ag nanoparticles (NPs) functionalized by 3 MgO monolayers (MLs). Ag NPs were synthesized by an aerosol method and MgO was grown by atomic layer deposition (ALD). The NPs geometry was tuned to obtain broadband >50% absorption in the entire blue range as evidenced by UV-vis. spectroscopy. The WF of 3 MgO MLs/Ag NPs multilayer was reduced by 1 eV compared to bare NPs, from 5 to 4 eV, as evidenced by UPS and Kelvin probe. Reduction by 1 eV is maximal for this pair of materials, and agrees well with experimental and theoretical findings. While the effect on WF is indeed significant, a special handling protocol for Ag before depositing MgO is a must. It would preserve a clean Ag surface with a WF of nearly 4 eV to achieve 3 eV upon ALD of MgO. This and other issues are under study to promote photocathode applications.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI058

Export •

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

MOPRI064

First Test Results from SRF Photoinjector for the R&D ERL at BNL

gun, SRF, cathode, cavity

748

D. Kayran, Z. Altinbas, D.R. Beavis, S.A. Belomestnykh, I. Ben-Zvi, J. Dai, S. Deonarine, D.M. Gassner, R.C. Gupta, H. Hahn, L.R. Hammons, C. Ho, J.P. Jamilkowski, P. Kankiya, N. Laloudakis, R.F. Lambiase, V. Litvinenko, G.J. Mahler, L. Masi, G.T. McIntyre, T.A. Miller, D. Phillips, V. Ptitsyn, T. Rao, T. Seda, B. Sheehy, K.S. Smith, A.N. Steszyn, T.N. Tallerico, R. Than, R.J. Todd, E. Wang, D. Weiss, M. Wilinski, W. Xu, A. Zaltsman
BNL, Upton, Long Island, New York, USA
S.A. Belomestnykh, I. Ben-Zvi, J. Dai, L.R. Hammons, V. Litvinenko, V. Ptitsyn
Stony Brook University, Stony Brook, USA

Funding: This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE and DOE grant at Stony Brook, DE-SC0005713.
An ampere class 20 MeV superconducting Energy Recovery Linac (ERL) is presently under commissioning at Brookhaven National Laboratory (BNL). This facility enables testing of concepts relevant for high-energy coherent electron cooling, electron-ion colliders, and high repetition rate Free-Electron Lasers. The ERL will be capable of providing electron beams with sufficient quality to produce high repetition rate THz and X-ray radiation. When completed the SRF photoinjector will provide 2 MeV energy and 300 mA average beam current. The injector for the R&D ERL was installed in 2012, this includes a 704MHz SRF gun* with multi-alkali photocathode, cryo-system upgrade and a novel emittance preservation zigzag-like low energy merger system. We describe the design and major components of the R&D ERL injector then report the first experimental results and experiences learned in the first stage of beam commissioning of the BNL R&D ERL.
* Wencan Xu et al., “Commissioning SRF gun for the R&D ERL at BNL”, IPAC2013 proceedings, WEPWO085.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI064

Export •

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

MOPRI066

External Neutron Source for Research Reactor Based on Linear Accelerator and Beryllium Target

target, neutron, radiation, experiment

754

V.P. Struev, A.A. Bogdanov, A.G. Golovkina, Yu.V. Kiselev, I.V. Kudinovich, A.I. Laikin, S.M. Rubanov
KSRC, St. Petersburg, Russia
A.G. Golovkina, I.V. Kudinovich
St. Petersburg State University, St. Petersburg, Russia

Nuclear research reactor “U-3” of Krylov State Research Center was operated as an experimental tool to study a radiation shield of small nuclear power plants, radiation resistance of its equipment including control system elements. Reactor thermal output power is 50 kW. Currently reactor modernization is being carried out, in the framework of which neutron lighting system that consists of a linear electron accelerator “UEL-10D” (10 MeV) and a beryllium target is implemented. At the present time the neutron yield from the target experiments are going on, some obtained experimental results are presented. Optimal target sizes with a view to neutron yield were defined.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI066

Export •

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

MOPRI067

Beam Cooling Systems and Activities at GSI and FAIR

experiment, ion, pick-up, antiproton

757

C. Dimopoulou
GSI, Darmstadt, Germany

Efficient and versatile beam cooling (electron and stochastic cooling) has been an indispensable ingredient for beam preparation and physics experiments at the GSI accelerator complex. The hot secondary beams emerging from the production targets can hardly be used, unless they are cooled. Beam stacking of low-abundant species relies on cooling. Cooling enables high-precision experiments with stored beams, counteracts the heating during internal target operation and controls decelerated beams. New challenges lie ahead within the FAIR project like (i) the ongoing integration downstream of the ESR of the low-energy CRYRING with its electron cooler, (ii) the developments for the demanding CR stochastic cooling system, (iii) the stacking scenarios with RF and stochastic cooling in the HESR/RESR. The function and parameters of the existing and future beam cooling systems are summarized. We report on the latest hardware developments as well as on improvements of the controls and operation software. Recent highlights and results from beam manipulations with cooling at GSI are shown. In focus are those benchmarking experiments, where the concepts for the new FAIR systems are verified.
C. Dimopoulou on behalf of the GSI Beam Cooling Department, of the GSI Stored Beams Division and of the FAIR Project Team.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI067

Export •

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

MOPRI070

2MeV Electron Cooler for COSY and HESR – First Results

proton, experiment, operation, heavy-ion

765

V. Kamerdzhiev, U. Bechstedt, F.M. Esser, O. Felden, R. Gebel, A.J. Halama, F. Klehr, G. Langenberg, A. Lehrach, B. Lorentz, R. Maier, D. Prasuhn, K. Reimers, M. Retzlaff, R. Stassen, H. Stockhorst, R. Tölle
FZJ, Jülich, Germany
N. Alinovskiy, T.V. Bedareva, E.A. Bekhtenev, O.V. Belikov, V.N. Bocharov, V.V. Borodich, M.I. Bryzgunov, A.V. Bubley, V.A. Chekavinskiy, V.G. Cheskidov, B.A. Dovzhenko, A.I. Erokhin, M.G. Fedotov, A.D. Goncharov, K. Gorchakov, V.K. Gosteev, I.A. Gusev, G.V. Karpov, Y.I. Koisin, M.N. Kondaurov, V.R. Kozak, A.M. Kruchkov, A.D. Lisitsyn, I.A. Lopatkin, V.R. Mamkin, A.S. Medvedko, V.M. Panasyuk, V.V. Parkhomchuk, I.V. Poletaev, V.A. Polukhin, A.Yu. Protopopov, D.N. Pureskin, A.A. Putmakov, V.B. Reva, P.A. Selivanov, E.P. Semenov, D.V. Senkov, D.N. Skorobogatov, N.P. Zapiatkin
BINP SB RAS, Novosibirsk, Russia
J. Dietrich
HIM, Mainz, Germany
T. Katayama
Nihon University, Narashino, Chiba, Japan
L.J. Mao
IMP, Lanzhou, People's Republic of China

The 2 MeV electron cooler was installed in the COSY ring in the spring 2013. The new system enables electron cooling in the whole energy range of COSY. The electron beam is guided by longitudinal magnetic field all the way from the electron gun to the collector. This well-proven optics scheme was chosen because of the wide electron energy range of 0.025-2 MeV. The electrostatic accelerator consists of 33 individual sections of identical design. Electrical power to each section is provided by a cascade transformer. Electron beam commissioning and first studies using proton and deuteron beams were carried out. Electron cooling of proton beam up to 1662 MeV kinetic energy was demonstrated. Maximum electron beam energy achieved so far amounted to 1.25 MeV. Voltage up to 1.4 MV was demonstrated. The cooler was operated with electron current up to 0.5 A. The paper provides insights into the recent progress in high energy electron cooling at COSY and perspectives for the HESR ring at FAIR.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI070

Export •

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

MOPRI073

Status of the HESR Electron Cooler Test Set-up

gun, diagnostics, solenoid, vacuum

771

M.W. Bruker, K. Aulenbacher, J. Dietrich, S. Friederich, T. Weilbach
HIM, Mainz, Germany
K. Aulenbacher
IKP, Mainz, Germany

For the High Energy Storage Ring (HESR) at FAIR, it is planned to install an electron cooling device with a beam current of 3 A and a beam energy of 8 MeV. A test set-up was built at Helmholtz-Insitut Mainz (HIM) to conduct a feasibility study. One of the main goals of the test set-up is to evaluate the gun design proposed by TSL (Uppsala) with respect to vacuum handling, electric and magnetic fields, and the resulting beam parameters. Another purpose of the set-up is to reduce recuperation losses to less than 10^-5. To measure this quantity and to mitigate collection losses, a Wien filter has been designed and installed. Beam diagnostics will be carried out with a COSY-style beam position monitor. The latest progress of the project is presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI073

Export •

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

MOPRI074

Conceptual Project Relativistic Electron Cooler for FAIR/HESR

proton, high-voltage, acceleration, cathode

774

V.V. Parkhomchuk, M.I. Bryzgunov, A.P. Denisov, V.M. Panasiuk, V.B. Reva
BINP SB RAS, Novosibirsk, Russia
K. Aulenbacher, J. Dietrich
HIM, Mainz, Germany
V. Kamerdzhiev
FZJ, Jülich, Germany

To develop a 4 MeV relativistic electron cooling system for the HESR storage ring, which is part of the future GSI facility FAIR, is proposed to further boost the luminosity even with strong heating effects of high-density internal targets. In addition the upgrade to 8 MeV of the relativistic electron cooler is essential for the future Electron Nucleon Collider (ENC@FAIR) project. The basic feature of the design are the power for magnet field coils at accelerating and decelerating column is generated by turbines (one option under investigation in this research group) operated on SF6 gas under pressure

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI074

Export •

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

MOPRI075

COSY 2 MeV Cooler: Design, Diagnostic and Commissioning

controls, gun, ion, diagnostics

777

V.B. Reva, N. Alinovskiy, T.V. Bedareva, E.A. Bekhtenev, O.V. Belikov, V.N. Bocharov, V.V. Borodich, M.I. Bryzgunov, A.V. Bubley, V.A. Chekavinskiy, V.G. Cheskidov, B.A. Dovzhenko, A.I. Erokhin, M.G. Fedotov, A.D. Goncharov, K. Gorchakov, V.K. Gosteev, I.A. Gusev, A.V. Ivanov, G.V. Karpov, Y.I. Koisin, M.N. Kondaurov, V.R. Kozak, A.D. Lisitsyn, I.A. Lopatkin, V.R. Mamkin, A.S. Medvedko, V.M. Panasyuk, V.V. Parkhomchuk, I.V. Poletaev, V.A. Polukhin, A.Yu. Protopopov, D.N. Pureskin, A.A. Putmakov, P.A. Selivanov, E.P. Semenov, D.V. Senkov, D.N. Skorobogatov, N.P. Zapiatkin
BINP SB RAS, Novosibirsk, Russia
J. Dietrich
DELTA, Dortmund, Germany
V. Kamerdzhiev, L.J. Mao
FZJ, Jülich, Germany

The 2 MeV electron cooling system for COSY-Julich was proposed to further boost the luminosity in presence of strong heating effects of high-density internal targets. The 2 MeV cooler is also well suited in the start up phase of the High Energy Storage Ring (HESR) at FAIR in Darmstadt. It can be used for beam cooling at injection energy and for testing new features of the high energy electron cooler for HESR. The COSY cooler is designed on the classic scheme of low energy coolers like cooler CSRm, CSRe, LEIR that was produced in BINP before. The electron beam is transported inside the longitudinal magnetic field along whole trajectory from an electron gun to a collector. This optic scheme is stimulated by the wide range of the working energies 0.025-2 MeV. The electrostatic accelerator consists of 33 individual unify section. Each section contains two HV power supply and power supply of the magnetic coils. The electrical power to each section is provided by a cascade transformer. This report describes the cooler design, diagnostics, control system and the result of the commissioning in BINP and FZJ at the different energies.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI075

Export •

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

MOPRI088

Beam Transport Experiments Using Gabor Lenses

beam-transport, experiment, focusing, space-charge

818

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

A prototype Gabor lens has successfully been tested at the GSI High Current Test Injector (HOSTI)*. The experiments comprised the investigation of an emittance dominated and a space-charge dominated beam transport. In particular, the high-current measurements represent a necessary step towards evaluating the focusing performance of the lens and to gain experience in a real accelerator environment. Besides the evaluation of the technical feasibility, the behavior of the electron cloud was characterized by the parameter analysis of the confined non-neutral plasma during beam transport measurements as well as subsequently performed diagnostic experiments. This contribution will present experimental results as well as numerical studies on an improved Gabor lens design for the possible application at the GSI High Current Injector (HSI) in the context of an upgrade program for FAIR**.
*K. Schulte et al., Proc. of IPAC'13, Shanghai, China, 2013, THPWO021
**L. Dahl, Proc. of HIAT’09, Venice, Italy, 2009, FR-01

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI088

Export •

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

TUOAA03

Extra Low ENergy Antiproton ring ELENA: From the Conception to the Implementation Phase

experiment, antiproton, emittance, extraction

910

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

The Extra Low Energy Antiproton ring (ELENA) is a CERN project aiming at constructing a small 30 m circumference synchrotron to further decelerate antiprotons from the Antiproton Decelerator AD from 5.3 MeV to 100 keV. Controlled deceleration in a synchrotron equipped with an electron cooler to reduce emittances in all three planes will allow the existing AD experiments to increase substantially their antiproton capture efficiencies and render new experiments possible. The ELENA design is now well advanced and the project is moving to the implementation phase. Component design and construction are taking place at present for installation foreseen during the second half of 2015 and beginning of 2016 followed by ring commissioning until the end of 2016. New electrostatic transfer lines to the experiments will be installed and commissioned during the first half of 2017 followed by the first physics operation with ELENA. Basic limitations like Intra Beam Scattering limiting the emittances obtained under electron cooling and direct space charge effects will be reviewed and the status of the project will be reported.

Slides TUOAA03 [4.963 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOAA03

Export •

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

TUYA01

First Experience with Electron Lenses for Beam-beam Compensation in RHIC

solenoid, emittance, hadron, proton

913

W. Fischer, Z. Altinbas, D. Bruno, M.R. Costanzo, X. Gu, J. Hock, A.K. Jain, Y. Luo, C. Mi, R.J. Michnoff, T.A. Miller, A.I. Pikin, T. Samms, Y. Tan, R. Than, P. Thieberger, S.M. White
BNL, Upton, Long Island, New York, USA

Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH10886 with the U.S. Department of Energy.
The head-on beam-beam interaction is the dominant luminosity limiting effect in polarized proton operation in RHIC. To mitigate this effect two electron lenses were installed in the two RHIC rings. We summarize the hardware and electron beam commissioning results to date, and report on the first experience with the electron-hadron beam interaction. In 2014 RHIC is operating with gold beams only. In this case the luminosity is not limited by head-on beam-beam interactions and compensation is not necessary. The goals of this year’s commissioning efforts are a test of all instrumentation; the demonstration of electron and gold beam overlap; the demonstration of electron beam parameters that are sufficiently stable to have no negative impact on the gold beam lifetime; and the measurement of the tune footprint compression from the beam overlap. With these demonstrations, and a lattice with a phase advance that has a multiple of 180 degrees between the beam-beam interaction and electron lens locations, head-on beam-beam compensation can be commissioned in the following year with proton beams.

Slides TUYA01 [11.776 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUYA01

Export •

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

TUOBA01

Electron Lenses for the Large Hadron Collider

collider, collimation, controls, operation

918

G. Stancari, A. Valishev
Fermilab, Batavia, Illinois, USA
R. Bruce, S. Redaelli, A. Rossi, B. Salvachua
CERN, Geneva, Switzerland

Funding: Fermi Research Alliance, LLC operates Fermilab under Contract DE-AC02-07CH11359 with the US Department of Energy. Research supported in part by US LARP and EU FP7 HiLumi LHC, Grant Agreement 284404.
Electron lenses are pulsed, magnetically confined electron beams whose current-density profile is shaped to obtain the desired effect on the circulating beam. Electron lenses were used in the Fermilab Tevatron collider for bunch-by-bunch compensation of long-range beam-beam tune shifts, for removal of uncaptured particles in the abort gap, for preliminary experiments on head-on beam-beam compensation, and for the demonstration of halo scraping with hollow electron beams. Electron lenses for beam-beam compensation are being commissioned in RHIC at BNL. Within the US LHC Accelerator Research Program and the European HiLumi LHC Design Study, hollow electron beam collimation was studied as an option to complement the collimation system for the LHC upgrades. This project is moving towards a technical design in 2014, with the goal to build the devices in 2015-2017, after resuming LHC operations and re-assessing needs and requirements at 6.5 TeV. Because of their electric charge and the absence of materials close to the proton beam, electron lenses may also provide an alternative to wires for long-range beam-beam compensation in LHC luminosity upgrade scenarios with small crossing angles.

Slides TUOBA01 [9.709 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOBA01

Export •

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

TUOBA02

Design Study of an ERL Test Facility at CERN

cryomodule, cavity, linac, optics

921

E. Jensen, C. Bracco, O.S. Brüning, R. Calaga, N. Catalán Lasheras, B. Goddard, R. Torres-Sanchez, A. Valloni
CERN, Geneva, Switzerland
M. Klein
The University of Liverpool, Liverpool, United Kingdom

The modern concept of an Energy Recovery Linac allows providing large electron currents at large beam energy with low power consumption. This concept is used in FEL’s, electron-ion colliders and electron coolers. CERN has started a Design Study of an ERL Test Facility with the purpose of 1) studying the ERL principle, its specific beam dynamics and operational issues, as relevant for LHeC, 2) providing a test bed for superconducting cavity modules, cryogenics and integration, 3) studying beam induced quenches in superconducting magnets and protection methods, 4) providing test beams for detector R&D and other applications. It will be complementary to existing or planned facilities and is fostering international collaboration. The operating frequency of 802 MHz was chosen for performance and for optimum synergy with SPS and LHC; the design of the cryomodule has started. The ERL Test Facility can be constructed in stages from initially 150 MeV to ultimately 1 GeV in 3 passes, with beam currents of up to 80 mA. Parameters to serve the above-mentioned purposes are well defined and possible lattice designs have well advanced.

Slides TUOBA02 [14.419 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOBA02

Export •

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

TUOBA03

Recent Beam-beam Effects and Luminosity at VEPP-2000

luminosity, collider, positron, detector

924

D.B. Shwartz, D.E. Berkaev, A.S. Kasaev, I. Koop, A.N. Kyrpotin, A.P. Lysenko, E. Perevedentsev, V.P. Prosvetov, Yu. A. Rogovsky, A.L. Romanov, A.I. Senchenko, P.Yu. Shatunov, Y.M. Shatunov, I.M. Zemlyansky, Yu.M. Zharinov
BINP SB RAS, Novosibirsk, Russia

Funding: Work is supported by the Ministry of Education and Science of the Russian Federation, grant N 14.518.11.7003
VEPP-2000's last season was dedicated to the energy range of 160-520 MeV per beam. The application of round colliding beams concept along with the accurate orbit and lattice correction yielded the high peak luminosity of 1.2*10³¹ cm^-2s⁻¹ at 500 MeV with average luminosity of 0.9*10³¹ cm^-2s⁻¹ per run. The total beam-beam tune shift up to 0.174 was achieved in the runs at 392.5 MeV. This corresponds to beam-beam parameter ksi = 0.125 per one interaction point. The injection system is currently being upgraded to allow for the injection at the top energy of VEPP-2000 collider and to eliminate the present lack of positrons.

Slides TUOBA03 [4.475 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOBA03

Export •

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

TUZA01

Advanced Concepts and Challenges in Compton Radiation Sources

laser, plasma, cavity, photon

928

I. Pogorelsky
BNL, Upton, Long Island, New York, USA

Ongoing developments in Compton radiation sources are aimed toward a diversity of potential applications, ranging from university-scale compact x-ray light sources and metrology tools for EUV lithography, to positron sources for e⁻e⁺ colliders. Novel conceptual approaches are pursued on different routes: One research direction lies in multiplying the source’s repetition rate and increasing its average brightness by placing the point of Compton interaction inside an optical cavity. High-gradient plasma-wakefield accelerators are fast becoming a practical reality, offering a new paradigm to compact all-optical Compton sources operating in x-ray- and gamma-regions. Continuing improvement in the quality of the beam of plasma accelerators promises the achievement of fully coherent Compton x-rays, thereby prompting the evolution of the Compton source to an all-optical free-electron laser.

Slides TUZA01 [22.419 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUZA01

Export •

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

TUZA02

THz Facility at ELBE: A Versatile Test Facility for Electron Bunch Diagnostics on Quasi-CW Electron Beams

diagnostics, SRF, operation, linac

933

M. Gensch, B.W. Green, J. Hauser, S. Kovalev, M. Kuntzsch, U. Lehnert, P. Michel, R. Schurig
HZDR, Dresden, Germany
A. Al-Shemmary, V. B. Asgekar, T. Golz, H. Schlarb, N. Stojanovic, S. Vilcins
DESY, Hamburg, Germany
A.S. Fisher
SLAC, Menlo Park, California, USA
G. Geloni
XFEL. EU, Hamburg, Germany
A.-S. Müller, M. Schwarz
KIT, Karlsruhe, Germany
N.E. Neumann, D. Plettemeier
TU Dresden, Dresden, Germany

At the Helmholtz-Zentrum Dresden-Rossendorf near Dresden a quasi-cw low-energy electron linear accelerator based on superconducting radiofrequency technology is operated successfully for more than 10 years. The ELBE accelerator is driving several secondary radiation sources including 2 infrared free electron lasers. A new addition will be a THz facility that aims to make use of super-radiant THz radiation. In its final form the THz facility shall consist of one coherent diffraction radiator and one undulator source which provide high-field THz pulses at unprecedented repetition rates. While the medium term goal is to establish a unique user facility for nonlinear THz science, the THz sources are already used as a test facility for novel diagnostic techniques on quasi-cw electron beams. The progress of the developments is reported and an outlook into future challenges and opportunities is given.

Slides TUZA02 [3.041 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUZA02

Export •

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

TUOCA01

The Linac Coherent Light Source-II Project

linac, undulator, cryomodule, laser

935

J.N. Galayda
SLAC, Menlo Park, California, USA

Funding: Work supported by US DOE Contract DE-AC02-766SF00515
The “Linac Coherent Light Source–II” Project, initiated in September 2010, has gone through a radical transformation beginning in August 2013. In its new form, LCLS-II will construct a 4 GeV CW superconducting linac in the first kilometre of the existing linac tunnel. A new undulator, optimized as a soft x-ray (200-1,300 eV) source, will receive electrons from the new SC linac. The existing undulator system will be replaced with a new variable gap device, which will receive electrons from either the new SC linac (providing 1-5 keV photons) or the copper linac presently used by LCLS (providing 1-25 keV x-rays). First light from the new facility is expected in September 2019.
galayda@slac.stanford.edu

Slides TUOCA01 [9.380 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOCA01

Export •

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

TUOCA03

Production of Quasi-monochromatic GeV Photons by Compton Scattering using Undulator X-ray Radiation at SPring-8

photon, undulator, laser, experiment

941

H. Ohkuma, A. Mochihashi, M. Oishi, S. Suzuki, K. Tamura
JASRI/SPring-8, Hyogo-ken, Japan
N. Muramatsu, H. Shimizu
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
T. Nakano
RCNP, Osaka, Japan

Funding: This work is supported by JSPS KAKENHI (Grant-in-Aid for Scientific Research) Grant Number 24241035.
Backward Compton scattering (BCS) of X-ray photons emitted by undulator and reflected back by a single crystal from the electron beam can produce a quasi-monochromatic gamma-ray beam up to an energy very close to the electron beam energy. The SPring-8 beam diagnostics beamline (BL05SS) is used to inject a reflected undulator X-ray radiation against 8 GeV stored electron beam and to extract a quasi-monochromatic 8 GeV gamma-ray produced by BCS. BL05SS has conditions to do a pilot experiment to obtain the gamma-ray beam using BCS of X-ray photons from existing undulator. Experimental setup including a Bragg mirror system is now under construction. Preliminary reflectivity measurement of a silicon Bragg mirror using around 10keV photons has been done. Status of the experimental preparation and the future outlook is presented.

Slides TUOCA03 [1.889 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOCA03

Export •

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

TUXB01

Recent Progress in 3D Numerical Wakefield Calculations

impedance, cavity, insertion, damping

944

W. Bruns
WBFB, Berlin, Germany

The 3D electromagnetic Field Simulator GdfidL computes Wakepotentials on standard CPUs with a Speed comparable to GPU-Based Implementations. This is achieved via Computing only in interesting Cells, having the FD-Coefficients in compressed Form, traversing the Grid in a Cache-friendly Order and applying a blocked Update Scheme which is NuMA-aware. A Dispersion optimised Scheme is described. Fields in dispersive Materials are computed via solving the Equations of the Electron Hulls of the Material. Moving Mesh Computations have the Grid-generation on the Fly.

Slides TUXB01 [16.169 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUXB01

Export •

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

TUOBB01

Accelerator Physics Challenges towards a Plasma Accelerator with Usable Beam Quality

plasma, laser, acceleration, wakefield

961

R.W. Aßmann, J. Grebenyuk
DESY, Hamburg, Germany

Enormous progress in compact plasma accelerators has been demonstrated over the recent years in various experiments. These experiments rely on high power, pulsed lasers or short electron bunches to excite ultra-strong wakefields in plasmas. Accelerating gradients have reached several 10 GV/m up to 100 GV/m and the absolute energy gain of electron beams is in the regime of several GeV to 30 GeV. The principle and potential of plasma accelerators has been proven impressively and performance parameters are steadily improving. It is noted that particle accelerators are powerful tools that are ultimately justified by their applications in science, medicine or industry. The demonstration of useable beam quality and a realistic use case remains to be achieved for plasma accelerators. The accelerator physics challenges to arrive at this goal are analyzed and discussed.

Slides TUOBB01 [12.407 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOBB01

Export •

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

TUOBB02

Demonstration of Gigavolt-per-meter Accelerating Gradients using Cylindrical Dielectric-lined Waveguides

experiment, wakefield, radiation, laser

965

B.D. O'Shea, G. Andonian, K.L. Fitzmorris, J. Harrison, J.B. Rosenzweig, O. Williams
UCLA, Los Angeles, California, USA
M.J. Hogan, V. Yakimenko
SLAC, Menlo Park, California, USA

We present here the results of measurements made showing ~1 GV/m accelerating fields using a hollow dielectric-lined waveguide. The results are comprised of measurement of the energy loss of a high charge (~3 nC) ultrashort (~200 fs), ultra relativistic (20 GeV) beam and concomitant auto-correlation interferometeric techniques to obtain the frequency content of simultaneously generated coherent Cherenkov radiation (CCR). Experiments were conducted at the Facility for Advanced aCcelerator Experimental Tests (FACET) at the SLAC National Laboratory using metal-coated sub-millimeter diameter, ten-centimeter long fused silica tubes. We present simulation and theoretical results in support of the conclusions reached through experiment. These results build on previous work to provide a path towards high gradient accelerating structures for use in compact accelerator schemes, future linear colliders and free-electron lasers.

Slides TUOBB02 [2.349 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOBB02

Export •

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

TUPRO005

Status of the NICA Project at JINR

ion, collider, booster, experiment

1003

G.V. Trubnikov, N.N. Agapov, A.V. Butenko, D.E. Donets, E.D. Donets, E.E. Donets, A.V. Eliseev, E.V. Gorbachev, A. Govorov, E.V. Ivanov, V. Karpinsky, V.D. Kekelidze, H.G. Khodzhibagiyan, S.A. Kostromin, A.D. Kovalenko, O.S. Kozlov, V.A. Matveev, I.N. Meshkov, V.A. Mikhailov, V. Monchinsky, N. Shurkhno, A.O. Sidorin, I. Slepnev, V. Slepnev, A.V. Smirnov, A. Sorin, N.D. Topilin, A. Tuzikov, V. Volkov
JINR, Dubna, Moscow Region, Russia
O.I. Brovko, A.V. Philippov, N.V. Semin
JINR/VBLHEP, Moscow, Russia

Nuclotron-based Ion Collider fAcility (NICA) is the new accelerator complex being constructed in Joint Institute for Nuclear Research. General goal of the project is to provide experimental study of hot and dense strongly interacting QCD matter. The development of NICA injection complex is actively performed. Construction of new 3.2 MeV/u heavy-ion linear accelerator (HILac) is now under way in Germany. Construction of booster has been started. In this report the present status of the NICA accelerator complex are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO005

Export •

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

TUPRO017

HL-LHC Performance with a 200 MHz RF System

luminosity, impedance, cavity, simulation

1043

R. Tomás, C.O. Domínguez
CERN, Geneva, Switzerland
S.M. White
BNL, Upton, Long Island, New York, USA

The HL-LHC performance could considerably benefit from having a 200 MHz RF system. This would allow to inject longer bunches with larger bunch intensity from the SPS and to perform bunch length leveling if required. We also consider the possibility of decreasing the crab cavity frequency to increase both virtual peak luminosity and luminous region. Performance estimates of various configurations are presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO017

Export •

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

TUPRO029

Reducing Backgrounds in the Higgs Factory Muon Collider Detector

detector, background, photon, neutron

1081

S.I. Striganov, N.V. Mokhov, I.S. Tropin
Fermilab, Batavia, Illinois, USA

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy through the DOE Muon Accelerator Program (MAP).
A preliminary design of the 125-GeV Higgs Factory (HF) Muon Collider (MC) has identified an enormous background loads on the HF detector. This is related to the twelve times higher muon decay probability at HF compared to that previously studied for the 1.5-TeV MC. As a result of MARS15 optimization studies, it is shown that with a carefully designed protection system in the interaction region, in the machine-detector interface and inside the detector one can reduce the background rates to a manageable level similar to that achieved for the optimized 1.5-TeV case. The main characteristics of the HF detector background are presented for the configuration found.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO029

Export •

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

TUPRO032

RHIC Performance for FY2014 Heavy Ion Run

luminosity, kicker, cavity, ion

1090

G. Robert-Demolaize, J.G. Alessi, M. Bai, E.N. Beebe, J. Beebe-Wang, S.A. Belomestnykh, I. Blackler, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, J.J. Butler, R. Connolly, T. D'Ottavio, K.A. Drees, A.V. Fedotov, W. Fischer, C.J. Gardner, D.M. Gassner, X. Gu, M. Harvey, T. Hayes, H. Huang, P.F. Ingrassia, J.P. Jamilkowski, N.A. Kling, J.S. Laster, C. Liu, Y. Luo, D. Maffei, Y. Makdisi, M. Mapes, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, C. Naylor, S. Nemesure, A.I. Pikin, P.H. Pile, V. Ptitsyn, D. Raparia, T. Roser, P. Sampson, J. Sandberg, V. Schoefer, C. Schultheiss, F. Severino, T.C. Shrey, K.S. Smith, S. Tepikian, P. Thieberger, D. Trbojevic, J.E. Tuozzolo, B. Van Kuik, M. Wilinski, Q. Wu, A. Zaltsman, K. Zeno, W. Zhang
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.
After running uranium-uranium and copper-gold collisions in 2012, the high energy heavy ion run of the Relativistic Heavy Ion Collider (RHIC) for Fiscal Year 14 (Run14) is back to gold-gold (Au-Au) collisions at 100 GeV/nucleon. Following the level of performance achieved in Run12, RHIC is still looking to push both instantaneous and integrated luminosity goals. To that end, a new 56 MHz superconducting RF cavity was installed and commissioned, designed to keep ions in one RF bucket and improve luminosity by allowing a smaller beta function at the interaction point (IP) due to a reduced hourglass effect. The following presents an overview of these changes and reviews the performance of the collider.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO032

Export •

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

TUPRO037

Suppression Techniques of CSR Induced Emittance Growth in ERL Arcs

emittance, simulation, synchrotron, betatron

1102

A.V. Bondarenko, T. Atkinson, A.N. Matveenko
HZB, Berlin, Germany

The Energy Recovery Linac (ERL) conception is a promising way of creating diffraction limited synchrotron light source. The high ERL beam quality (low emittance, short bunch and low energy spread) gives an opportunity to generate high brightness photon beams. One of the main requirements for the optic in such machines is the suppression of emittance growth. An important reason for beam degradation is the impact of Coherent Synchrotron Radiation (CSR) in bending magnets. CSR induced emittance dilution and methods of preservation both with and without compression are discussed in this article.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO037

Export •

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

TUPRO039

Optimizing Polarization with an Improved Integer Resonance Correction Scheme at ELSA

resonance, polarization, quadrupole, closed-orbit

1108

J.F. Schmidt, O. Boldt, F. Frommberger, W. Hillert, J.-P. Thiry
ELSA, Bonn, Germany

Funding: DFG
The Electron Stretcher Facility ELSA of Bonn University provides a polarized electron beam of up to 3.2 GeV. In the stretcher ring various depolarizing resonances are crossed during the fast energy ramp of 6 GeV/s. The high polarization degree of up to 70% can only be conserved by taking several appropriate countermeasures. Concerning integer resonances, additional harmonic horizontal fields are applied by orbit correction magnets around the ring to compensate the resonance driving fields. The correction field has to be adjusted by empirical optimization of polarization. Recent developments enhance this optimization process, especially at high energies: A new magnet system allows for higher correction amplitudes and shorter rising times. Furthermore, a modified correction scheme was implemented. It takes into account the additional fields of the quadrupole magnets, arising from the orbit response of the correction magnets.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO039

Export •

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

TUPRO040

High Bandwidth Closed Orbit Control for a Fast Ramping Electron Accelerator

closed-orbit, resonance, acceleration, polarization

1111

J.-P. Thiry, A. Dieckmann, F. Frommberger, W. Hillert, J.F. Schmidt
ELSA, Bonn, Germany

ELSA is a fast ramping stretcher ring capable of acceleration and storage of polarized electrons with energies up to 3.2 GeV. To preserve the initial degree of polarization, the acceleration is performed by a fast energy ramp with a maximum ramping speed of 6 GeV/s. During acceleration especially the vertical orbit needs to be continuously corrected so that the vertical rms deviation does not exceed 50 μm at any time. In order to compensate the so called integer resonances, which occur at certain energies, the orbit correction system further needs to provide additional, empirically determined, harmonic field distributions. A successful application of these combined correction measures requires a considerably high bandwidth of up to some 100 Hz. In our contribution we will have a closer look at the performance and the acquired bandwidth of the correction system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO040

Export •

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

TUPRO044

Bunch Compression of the Low-energy ELBE Electron Beam for Super-radiant THz Sources

radiation, linac, emittance, undulator

1123

U. Lehnert, P. Michel, R. Schurig
HZDR, Dresden, Germany
A.A. Aksoy
Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
P.E. Evtushenko
JLab, Newport News, Virginia, USA
J.M. Krämer
Danfysik A/S, Taastrup, Denmark

At the ELBE radiation source two super-radiant THz sources, a broad-band trasnsition/diffraction radiation source and a planar undulator narrow-band sourc are under commissioning. At present the facility is driven from the ELBE linac with a CW electron beam of 100kHz repetition rate and up to 100pC of bunch charge. With the upgraded SRF electron gun bunch charges up to 1nC will become available. For the beam energies in the 20-30 MeV range buch compression into the sub-200 fs range becomes a major challenge. We present beam dynamics calculation of the attempted bunch compression scheme as well as first measurements obtained during the commissioning.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO044

Export •

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

TUPRO051

Emittance Increase and Matching along the Tomography Module at PITZ

emittance, focusing, quadrupole, lattice

1144

G. Kourkafas, P. Boonpornprasert, J.D. Good, M. Groß, I.I. Isaev, D.K. Kalantaryan, M. Khojoyan, M. Krasilnikov, D. Malyutin, B. Marchetti, D. Melkumyan, M. Otevřel, T. Rublack, F. Stephan, G. Vashchenko
DESY Zeuthen, Zeuthen, Germany
G. Asova
INRNE, Sofia, Bulgaria
G. Pathak
Uni HH, Hamburg, Germany

The Photo Injector Test facility at DESY, Zeuthen site (PITZ), focuses on testing, characterizing and optimizing high brightness electron sources for free electron lasers. PITZ is equipped with a number of transverse emittance measurement stations, among which is the Phase Space Tomography (PST) module. A PST measurement requires a specific transport along the tomography lattice, which ideally rotates the beam in the normalized transverse phase space by 180 degrees in equidistant steps. A preceding matching section is used to provide an injection scheme that delivers the necessary beam parameters for the design transport along the tomography lattice. The high charge density and moderate energy of the electron bunch at PITZ contribute to significant space-charge forces which lead to emittance growth and consequent mismatches of the design parameters. This article presents and evaluates measurements of the emittance increase along the matching section of a 1 nC beam at 22 MeV/c under different focusing schemes.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO051

Export •

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

TUPRO053

Design and Optimization of Racetrack Microtron for Laser Compton Scattered Gamma-ray Sources

linac, simulation, dipole, injection

1150

R. Hajima
JAEA/ERL, Ibaraki, Japan
M. Ferdows
JAEA, Ibaraki-ken, Japan

Funding: This work is supported by Funds for Integrated Promotion of Social System Reform and Research and Development.
Racetrack microtron (RTM) is a compact accelerator to obtain electron beams with an energy above 100 MeV. Conventional RTM's have been designed to accelerate a train of electron bunch from a thermionic electron gun, where the bunch charge is typically 10 pC. In the industrial application of laser Compton scattered gamma-ray sources, RTM with 200-300 MeV electron energy will be a suitable device to produce 2-3 MeV gamma-ray beams. Single electron bunch from a photocathode RF gun is accelerated and a high-charge small-emittance beam is preferable in such RTM. In this paper, we adopt a simulation code, GPT, for design and optimization of RTM in view of high-charge and small-emittance beam generation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO053

Export •

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

TUPRO060

First Turn-by-turn Measurements for Beam Dynamics Studies at ALBA

kicker, injection, optics, sextupole

1171

Z. Martí, G. Benedetti, M. Carlà, A. Olmos
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain

This paper summarizes the tasks carried out to develop a turn-by-turn (TBT) measurement system at ALBA. These tasks mainly include testing the MAF firmware for the libera BPMs and implementing the necessary analytical tools to infer the beam dynamics parameters. TBT measurements using an injection kicker are presented. Linear and non-linear beam dynamics results are compared with LOCO. Results are still preliminary since a good agreement with the linear model has not been achieved yet.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO060

Export •

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

TUPRO070

LHeC IR Optics Design Integrated into the HL-LHC Lattice

quadrupole, proton, lattice, luminosity

1198

E. Cruz Alaniz, M. Korostelev, D. Newton
The University of Liverpool, Liverpool, United Kingdom
E. Cruz Alaniz, M. Korostelev, D. Newton
Cockcroft Institute, Warrington, Cheshire, United Kingdom
R. Tomás
CERN, Geneva, Switzerland

Funding: OPAC fellowship funded by European Union under contract PITN-GA-2011-289485
The LHeC is a proposed upgrade to the LHC to provide electron-proton collisions and explore the new regime of energy and intensity for lepton-nucleon scattering. The work presented here investigates optics and layout solutions allowing simultaneous nucleon-nucleon and lepton-nucleon collisions at separate interaction points compatible with the proposed HL-LHC lattice. A first lattice design has been proposed that collides proton beam 2 with the electron beam. The nominal design calls for a β^* (beta function in the interaction point ) of 10 cm using an extended version of the Achromatic Telescopic Squeezing (ATS) scheme, and a L* (distance to the inner triplet) of 10 m. Modifying these two parameters, β^* and L*, can provide benefits to the current design since the values of these parameters have direct effects on the luminosity, the natural chromaticity and the synchrotron radiation of the electron beam. This work aims to explore the range over which these parameters can be varied in order to achieve the desired goal.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO070

Export •

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

TUPRO074

Emittance Growth due to Multiple Coulomb Scattering in a Linear Collider based on Plasma Wakefield Acceleration

scattering, plasma, emittance, acceleration

1211

Ö. Mete, K. Hanahoe, G.X. Xia
UMAN, Manchester, United Kingdom
O. Karamyshev, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
M. Labiche
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
M. Wing
UCL, London, United Kingdom

Alternative acceleration technologies are currently under development for cost-effective, robust, compact and efficient solutions. One such technology is plasma wakefield accel- eration, driven by either a charged particle or laser beam. However, the potential issues must be studied in detail. In this paper, the emittance growth of the witness beam through elastic scattering from gaseous media is derived. The model is compared with the numerical studies.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO074

Export •

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

TUPRO076

Initial Experimental Analysis into the eRHIC Polarized Electron Beam Transport System

dipole, cathode, operation, network

1217

C. Yeckel, E. Dobrin, P. Holen, R.C. Miller, M. Stangenes, K.A. Thompson, L.W. Thompson
Stangenes Industries, Palo Alto, California, USA
I. Ben-Zvi, R.F. Lambiase, J. Skaritka, E. Wang
BNL, Upton, Long Island, New York, USA

Stangenes Industries is working closely with Brookhaven National Lab in the United States to develop the eRHIC future ion collider. The collider requires a polarized electron source with high average current, short bunch length and small emittance. An array of photocathodes with their beams funneled into a common trajectory is utilized to achieve the required beam current and cathode lifetime. Stangenes Industries is charged with delivering the prototype injector for preliminary beam studies that will lead to full implementation by 2020. This study focuses on the development of the of beam transport system extending from cathode to beam dump. A majority of the complexity involves the so called "combiner magnet" that acts as a high frequency-rotating dipole to bend each beam into the final common trajectory. Preliminary experiments into the feasibility of such a system are analyzed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO076

Export •

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

TUPRO078

AREAL Solenoid, Dipole and Steering Magnets Design and Performance

dipole, solenoid, simulation, magnet-design

1223

A.V. Tsakanian, H. Gagiyan, A.A. Gevorgyan, B. Grigoryan, V.G. Khachatryan, M. Manukyan, T.H. Mkrtchyan, S. Naghdalyan, A.S. Simonyan, V. V. Vardanyan
CANDLE SRI, Yerevan, Armenia

The AREAL solenoid, dipole and corrector magnets design, simulations and performance are presented. A solenoid magnet will be used for the focusing of the low energy (E~5MeV) electron beam after RF gun as well as in the beam diagnostic section. The magnetic iron cover of solenoid provides return path for magnetic field screening effectively the field in the outer space and concentrating it inside solenoid gap. The dipole magnet is part of the spectrometer for beam energy spread measurements. An Iron-free corrector magnet design allows independent horizontal and vertical beam steering. The design optimization and magnetic field calculations are performed using CST-EM Studio. A good agreement between measurements and simulations is obtained.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO078

Export •

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

TUPRO108

Design and Performance of the TPS DC Septum Magnet

septum, shielding, booster, simulation

1301

C.S. Yang, C.-H. Chang, Y.L. Chu, T.Y. Chung, C.-S. Hwang, F.-Y. Lin
NSRRC, Hsinchu, Taiwan

To decrease the loading on an AC septum magnet, a DC septum magnet was fabricated and applied to the extraction system of the booster ring at Taiwan Photon Source (TPS). The minimal gap is 16.44 mm; the core length is 800 mm and the pole width is 45 mm. The maximum peak field of the DC septum magnet is designed to be 0.95 T at 12 kA with 24-turn coils. The maximum bending angle of the electron beam passing through the septum magnet is 75.5 mrad. Because the electron beam would be perturbed by the leakage field from the septum magnet, shielding between the septum magnet and the booster ring is an important issue for the operation of the beam. Here we report the shielding method with two materials of the DC septum magnet, and discuss the field mapping and shielding from the leakage field.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO108

Export •

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

TUPRO117

Magnet Design for the SNS Laser Stripping Experiment

laser, ion, experiment, operation

1328

A.V. Aleksandrov, A.A. Menshov
ORNL, Oak Ridge, Tennessee, USA

Funding: This work is funded by the U.S. DOE under grant number DE-FG02-13ER41967, and by the U.S. DOE under contract number DE-AC05-00OR22725 with UT-Battelle Corporation.
The first step in the three-step laser assisted H⁻ beam stripping for charge exchange injection is to remove one electron in a strong magnetic field. In order to preserve the beam emittance for the subsequent laser induced stripping of the second electron the magnetic field has to have large gradient of about 40 T/m along the beam trajectory. The required magnetic field strength for stripping 1GeV H⁻ beam is 1.2 T in 29 mm aperture. In order to allow for undisturbed passage of high power beam during the nominal SNS operation the stripping magnet made of permanent magnet material resides in vacuum chamber and can move in and out of the beam line. This presentation describes requirements and design and the magnetic field calculation results for a stripping magnet for the Laser Stripping Experiment at SNS.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO117

Export •

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

TUPME002

An Optimization of Positron Injector of ILC

positron, target, booster, linac

1334

M. Kuriki, Y. Seimiya
HU/AdSM, Higashi-Hiroshima, Japan
S. Kashiwagi
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
T. Okugi, M. Satoh, J. Urakawa
KEK, Ibaraki, Japan

Funding: This work is supported by Photon and Quantum Basic Research Coordinated Development Program of MEXT.
ILC (International Linear Collider) is a future project of high energy physics. In the current baseline design, positron generation by gamma rays from undulator radiation is assumed. However, this approach is totally new and it is very difficult to demonstrate the system prior to the construction because it requires more than 100 GeV beam as the driver. A conventional positron generation (e-driven) has been proposed as a technical backup option. In this method, the technology is well established, but the issue is to obtain an enough amount of positron with a manageable energy deposition on target. We present a result of a systematic study of capture efficiency defined by DR (Damping Ring) acceptance where the beam emittance is reduced by radiation damping. We performed a start-to-end simulation of the positron source of ILC and found that an enough amount of the positron per bunch is obtained with a manageable energy deposition on the production target.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME002

Export •

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

TUPME003

Effect of CSR Shielding in the Compact Linear Collider

shielding, radiation, simulation, synchrotron

1337

J. Esberg, R. Apsimon, A. Latina, D. Schulte
CERN, Geneva, Switzerland

The Drive Beam complex of the Compact LInear Collider must use short bunches with a large charge making beam transport susceptible to unwanted effects of Coherent Synchrotron Radiation emitted in the dipole magnets. We here present the effects of transporting the beam within a limited aperture which decreases the magnitude of the CSR wake. The effect, known as CSR shielding, eases the design of key components of the facility.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME003

Export •

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

TUPME035

Design Study of the Laser-driven Dielectric Accelerator

laser, acceleration, simulation, focusing

1428

K. Koyama, M. Yoshida
KEK, Ibaraki, Japan
Y. Matsumura
University of Tokyo, Tokyo, Japan
S. Otsuki
The University of Tokyo, Tokyo, Japan
M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan

Funding: This work was partly supported by KAKENHI, Grant-in-Aid for Scientific Research (C) 24510120.
Laser driven dielectric accelerators (LDA) are vigorously studied in order to apply to various fields in recent years. Characteristics of the LDA output such as sub-micron diameter, atto-second bunch and high acceleration field are suitable for in-situ investigating the biological effects of low doses of radiation in a living cell. The output energy of 1 MeV is sufficient for sniping a cell nucleus or DNA. Although the electronic charge in the bunch is in the order of 10 fC, the tightly focused beam enable to cause a local damage in the cell. We have reported optimum structure parameters of dielectric in the nonrelativistic regime. The low acceleration efficiency of slow electrons by short laser pulses is the serious problem. The accelerator length, laser intensity, pulse width, and optical system must be adjusted to design the practical LDA. We present the design principle of the LDA for nonrelativistic electrons and present status of the pumping laser of us.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME035

Export •

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

TUPME036

Simulation Study on Electron Beam Acceleration using Coherent Cherenkov Radiation

acceleration, simulation, radiation, laser

1431

K. Kan, M. Gohdo, T. Kondoh, K. Norizawa, I. Nozawa, A. Ogata, T. Toigawa, J. Yang, Y. Yoshida
ISIR, Osaka, Japan
M. Hangyo
ILE Osaka, Suita, Japan
R. Kuroda, H. Toyokawa
AIST, Tsukuba, Ibaraki, Japan

Beam diagnostics for electron bunch length using spectrum analysis of multimode terahertz (THz) -wave have been studied in ISIR, Osaka University*. The multimode THz-wave was generated by coherent Cherenkov radiation (CCR)** using hollow dielectric tubes and femtosecond/picosecond electron bunches. In this study, numerical calculation of acceleration and deceleration of electron beam using multimode THz-wave was carried out.
* K. Kan et al., Appl. Phys. Lett. 99, 231503 (2011).
** A. M. Cook et al., Phys. Rev. Lett. 103, 095003 (2009).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME036

Export •

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

TUPME037

Development on On-chip Radiation Source using Dielectric Laser Accelerator

laser, acceleration, radiation, simulation

1434

S. Otsuki
The University of Tokyo, Tokyo, Japan
K. Koyama, M. Yoshida
KEK, Ibaraki, Japan
Y. Matsumura
University of Tokyo, Tokyo, Japan
S. Mima
RIKEN, Japan
M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan

Funding: This work was partly supported by KAKENHI, Grant-in-Aid for Scientific Research (C) 24510120.
One of the state-of-the-art acceleration schemes, where high intensity laser pulses are modulated by dielectric grating structure such as quartz to accelerate charged particles, is dielectric laser acceleration (DLA)*. The difference of our DLA concept from other schemes is installation of a prism: the tilted wave-front in a prism shape refractive medium leads the suitable delay to match the phase advance of the electron beam. We plan to apply this method to build an on-chip radiation source which can hit and damage target elements of the cells. Such an application is useful in radiation biology, i.e., for investigation on bystander effects. The x-rays with small radius and adequate intensity required for this goal can be obtained using sub-micron beams from the small accelerating structure at high repetition rate (such as 50 kHz). In addition, the mass productivity of the DLA based on the consumer-grade laser and the photolithography has advantage compared to the conventional RF accelerator using high power klystrons. We will present field simulation and preliminary experimental results for demonstration on our concept of DLA.
* Demonstration of electron acceleration in a laser-driven dielectric microstructure, Nature 2013
** Laser-Based Acceleration of Nonrelativistic Electrons at a Dielectric Structure, Phys. Rev. 2013

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME037

Export •

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

TUPME041

The Advanced Superconducting Test Accelerator at Fermilab: Science Program

SRF, linac, emittance, laser

1447

P. Piot, E.R. Harms, S. Henderson, J.R. Leibfritz, S. Nagaitsev, V.D. Shiltsev, A. Valishev
Fermilab, Batavia, Illinois, USA

Funding: This work is supported by DOE contract DE-AC02-07CH11359 to the Fermi Research Alliance LLC
The Advanced Superconducting Test Accelerator (ASTA) currently in commissioning phase at Fermilab is foreseen to support a broad range of beam-based experiments to study fundamental limitations to beam intensity and to develop novel approaches to particle-beam generation, acceleration and manipulation. ASTA incorporates a superconducting radiofrequency (SCRF) linac coupled to a flexible high-brightness photoinjector. The facility also includes a small-circumference storage ring capable of storing electrons or protons. This report summarizes the facility capabilities, and provide an overview of the accelerator-science researches to be enabled.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME041

Export •

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

TUPME044

Planned High-brightness Channeling Radiation Experiment at Fermilab's Advanced Superconducting Test Accelerator

experiment, detector, radiation, photon

1457

B.R. Blomberg, D. Mihalcea, H. Panuganti, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
C.A. Brau, B.K. Choi, W.E. Gabella, B.L. Ivanov, M.H. Mendenhall
Vanderbilt University, Nashville, Tennessee, USA
C.W. Lynn
Swarthmore College, Swarthmore, Pennsylvania, USA
P. Piot, T. Sen
Fermilab, Batavia, Illinois, USA
W.S. Wagner
Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany

Funding: Work supported by the DARPA Axis program under contract AXIS N66001-11-1-4196
In this contribution we describe the technical details and experimental setup of our study aimed at producing high-brightness channeling radiation (CR) at Fermilab’s new user facility the Advanced Superconducting Test Accelerator (ASTA). In the ASTA photoinjector area electrons are accelerated up to 40-MeV and focused to a sub-micron spot on a ~40 micron thick carbon diamond, the electrons channel through the crystal and emit CR up to 80-KeV. Our study utilizes ASTA’s long pulse train capabilities and ability to preserve ultra-low emittance, to produce the desired high average brightness.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME044

Export •

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

TUPME046

3-D Particle-in-cell Simulations for Quasi-phase Matched Direct Laser Electron Acceleration in Density-modulated Plasma Waveguides

laser, plasma, emittance, simulation

1463

M.W. Lin
The Pennsylvania State University, University Park, Pennsylvania, USA
I. Jovanovic
Penn State University, University Park, Pennsylvania, USA

Funding: This work is supported by the Defense Threat Reduction Agency through contract HDTRA1-10-1-0034.
Quasi-phase matched (QPM) direct laser acceleration (DLA) of electrons can be realized with guided, radially polarized laser pulses in density-modulated plasma waveguides*,**. A 3-D particle-in-cell (PIC) simulation model has been developed to study the scheme in which an electron bunch from a laser wakefield accelerator (LWFA) is injected into a plasma waveguide for the second-stage DLA to higher energies. In addition to being driven directly by the laser field, the electrons also experience the laser pondermotive force and the electrostatic force from the excited plasma waves. The results lead to better understanding of the interactions between the electron bunch, the laser pulse and the background plasma. Selected bunch lengths, bunch sizes and time delays with respect to the laser pulse are assigned for the injected electrons in a series of simulations. The energy spectrum and emittance of the accelerated electron bunch vary depending on those initial conditions, and they can be chosen to optimize the DLA performance.
* P. Serafim, et al., IEEE Trans. Plasma Sci. 28, 1155 (2000).
** M. -W. Lin and I. Jovanovic, Phys. Plasmas 19, 113104 (2012).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME046

Export •

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

TUPME047

SINBAD - A Proposal for a Dedicated Accelerator Research Facility at DESY

plasma, experiment, laser, linac

1466

R.W. Aßmann, C. Behrens, R. Brinkmann, U. Dorda, K. Flöttmann, B. Foster, J. Grebenyuk, I. Hartl, M. Hüning, Y.C. Nie, J. Osterhoff, A. Rühl, H. Schlarb, B. Schmidt
DESY, Hamburg, Germany
M. Groß, B. Marchetti, F. Stephan
DESY Zeuthen, Zeuthen, Germany
F.J. Grüner, B. Hidding, A.R. Maier
Uni HH, Hamburg, Germany
F.X. Kärtner, B. Zeitler
CFEL, Hamburg, Germany
A.-S. Müller, M. Schuh
KIT, Karlsruhe, Germany

A new, dedicated accelerator research facility SINBAD (Short INnovative Bunches and Accelerators at DESY) is proposed. This facility is aimed at promoting two major goals: (1) Short electron bunches for ultra-fast science. (2) Construction of a plasma accelerator module with useable beam quality. Research and development on these topics is presently ongoing at various places at DESY, as add-on experiments at operational facilities. The two research goals are intimately connected: short bunches and precise femtosecond timing are requirements for developing a plasma accelerator module. The scientific case of a dedicated facility for accelerator research at DESY is discussed. Further options are mentioned, like the use of a 1 GeV beam from Linac2 for FEL studies and the setup of an attosecond radiation source with advanced technology. The presently planned conversion of the DORIS storage ring and its central halls into the SINBAD facility is described. The available space will allow setting up several independent experiments with a cost-effective use of the same infrastructure. National and international contributions and proposals can be envisaged.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME047

Export •

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

TUPME048

Injection of a LWFA Electron Bunch in a PWFA Driven by a Self-modulated-proton-bunch

plasma, wakefield, laser, experiment

1470

P. Muggli
MPI, Muenchen, Germany
L.D. Amorim
IST, Lisboa, Portugal
S. Karsch
MPQ, Garching, Munich, Germany
N.C. Lopes, J. Vieira
Instituto Superior Tecnico, Lisbon, Portugal

The AWAKE experiment recently approved at CERN will study the acceleration of an externally injected electron bunch in a plasma wakefield accelerator (PWFA) driven by a self-modulated proton bunch. We study the possibility of injecting a bunch created by a laser-driven plasma wakefield accelerator (LWFA). We consider a first plasma source used for self-modulation of the drive bunch and a gas discharge source for acceleration of the collinearly injected bunch. The LWFA produces an electron bunch very short when compared to the PWFA wavelength and with relatively large current, possibly allowing for loading of the wakefields. Short length and high current lead to a small final energy spread. Co-linear injection preserves the incoming bunch quality and insures trapping and acceleration of the whole bunch. The energy of the LWFA electron bunch can easily exceed the trapping energy and can be produced over only a few millimeters gas-jet plasma driven by a laser of relatively modest power by today’s standards. We explore the parameter space suitable for this injection scheme that is more compact, simpler to implement and more suitable for injection in the mm-size accelerator structure.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME048

Export •

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

TUPME050

Electron Bunch Self-modulation in Long Plasmas at SLAC FACET

plasma, wakefield, experiment, radiation

1476

P. Muggli
MPI, Muenchen, Germany
E. Adli, V.K.B. Olsen
University of Oslo, Oslo, Norway
L.D. Amorim
IST, Lisboa, Portugal
S.J. Gessner, M.J. Hogan, S.Z. Li, M.D. Litos
SLAC, Menlo Park, California, USA
C. Joshi, K.A. Marsh, W.B. Mori, N. Vafaei-Najafabadi
UCLA, Los Angeles, California, USA
N.C. Lopes, J. Vieira
Instituto Superior Tecnico, Lisbon, Portugal
O. Reimann
MPI-P, München, Germany

Funding: This work performed in part under DOE Contract DE-AC02-76SF00515.
We study the physics of self-modulation instability (SMI) of long, when compared to the wake wavelength, electron and positron bunches in pre-formed plasmas at SLAC-FACET. Self-modulation is the result of the action of focusing/defocusing transverse wakefields on the bunch radius. Self-modulation leads to observables such as overall defocusing of the bunch, periodic modulation of the bunch radius at the wake period and multi-GeV energy gain/loss by drive bunch particles. Defocusing is observed from OTR images, radial self-modulation from CTR spectra and interferometric traces and energy gain/loss from energy spectra with sub-GeV resolution. The plasma density is varied by changing the vapor density ionized by a laser/axicon system. The bunch length, radius and charge can also be varied. The SMI can be seeded using a notch collimator system. Numerical simulations indicate that seeding the SMI mitigates the hose instability. Hose instability can also be seeded, for example by using the RF deflecting cavity to impart a tilt to the incoming bunch axis. The overall experimental plan as well as the latest experimental results obtained with electron bunches will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME050

Export •

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

TUPME051

Self-Injection by Trapping of Plasma Electrons Oscillating in Rising Density Gradient at Vacuum-Plasma Interface

plasma, laser, injection, wakefield

1479

A. A. Sahai, T.C. Katsouleas
Duke ECE, Durham, North Carolina, USA
P. Muggli
MPI-P, München, Germany

Funding: DE-SC0010012, NSF-PHY-0936278
We model the trapping of plasma electrons within the density structures excited by a propagating energy source in a rising plasma density gradient. Rising density gradient leads to spatially contiguous coupled up-chirped plasmons (d{ω²_pe(x)}/{dx}>0). Therefore phase mixing between plasmons can lead to trapping until the plasmon field is high enough such that e^- trajectories returning towards a longer wavelength see a trapping potential. Rising plasma density gradients are ubiquitous for confining the plasma within sources at the vacuum-plasma interfaces. Therefore trapping of plasma-e^- in a rising ramp is important for acceleration diagnostics and to understand the energy dissipation from the excited plasmon train [1]. Down-ramp in density [2][3] has been used for plasma-e^- trapping within the first bucket behind the driver. Here, in rising density gradient the trapping does not occur in the first plasmon bucket but in subsequent plasmon buckets behind the driver. Trapping reduces the Hamiltonian of each bucket where e^- are trapped, so it is a wakefield-decay probe. Preliminary computational results for beam and laser-driven wakefield are shown.
1.Sahai, A. A. et.al.,Proc of IPAC2013, MOPAC10, Oct2013
2.Suk, H. et.al.,Phys. Rev.Lett. 86 2001 10.1103/PhysRevLett.86.1011
3.Dawson, J, Phys Rev 113 1959 10.1103/PhysRev.113.383

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME051

Export •

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

TUPME052

Enhanced Laser Ion Acceleration based on Near-Critical Density Plasma Lens

plasma, laser, target, acceleration

1483

Y.X. Geng, J.E. Chen, L.R.F. Li, Y.H. Li, Q. Liao, C. Lin, L.H.Y. Lu, Y.R. Lu, H. Wang, X.Q. Yan, Z.X. Yuan, S. Zhao, W.B. Zhao, Y.Y. Zhao, K. Zhu, B.Y. Zou
PKU, Beijing, People's Republic of China

The laser prepulse has large effect on ion acceleration driven by high power laser pulse. Recently, simulations show that with proper prepulse parameters, a near critical density pre-plasma can be generated in the front target. When the main laser pulse propagating in this pre-plasma, it can experience transverse Self-focusing, longitudinal profile steepening and prepluse cleaning at the same time, meaning its quality is spontaneously improved by this “plasma lens”.The effects can greatly improve the energy coupling efficiency of laser pulse into accelerated ions. A 3mJ Ti-Sapphire laser system has been built at PKU in order to experimentally study the pre-pulse effect on a solid target. Fluid simulation show that, after hundreds of picoseconds radiated with this laser pulse, the pre-plasma in front of the target will expand to near critical density with tens of micron scale length, which is suitable as a plasma lens to improve the ion acceleration. A laser interferometer system is built to measure the scale length and density evolution of plasma and the optimum condition of the pre-plasma has been searched using both Aluminum target and home-made DLC target.
H.Y.Wang et al, Laser shaping of a relativistic intense, short Gaussian pulse by a plasma lens, PRL, 107,265002, 2011

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME052

Export •

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

TUPME055

Room-temperature Burst-mode GHz and THz Pulse-train Photoinjector

laser, cathode, bunching, acceleration

1492

F.H. Chao, C.H. Chen, K.Y. Huang, Y.-C. Huang, Y.C. Wang, M.H. Wu
NTHU, Hsinchu, Taiwan
P.J. Chou
NSRRC, Hsinchu, Taiwan

A photoinjector usually generates an electron pulse with few ps pulse duration repeating at 10-100 Hz. The low-pulse rate limits the data rate in a number of applications. Although high-repetition-rate operation is possible from a superconducting accelerator, the high cost and complexity of a superconducting system prevent it from being widely used. In this paper, we present our study toward a burst-mode GHz/THz pulse train photoinjector operating at room temperature. For the GHz operation mode, we self-develop a driver laser system, generating tens of laser pulses at 2.856 GHz in an adjustable 5-10 ns temporal envelope repeating at 10 Hz. Upon illuminating the photocathode with the driver laser, our S-band photoinjector (supported by Tsing Hua University, Beijing) is to generate a GHz electron pulse train with the same temporal structure as that of the driver laser pulses. For the THz operation mode, we illuminate the photocathode with two lasers, one being a typical UV gun-driver laser at 260 nm and the other being a mid-infrared laser at 100 THz. The UV laser induces photoemission and the infrared laser gates the emission current at 100 THz by virtue of the Schottky effect.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME055

Export •

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

TUPME056

Improving Ion and Electron Beam Characteristics within LA³NET

laser, acceleration, photon, simulation

1495

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.
Lasers are widely used at accelerator and light source facilities for beam generation, acceleration and optimization. Research within LA³NET focuses on laser-based particle sources (photo injectors and laser ion sources), laser acceleration, and laser-based beam diagnostics. This project was recently selected as a ‘success story’ by the European Commission for its research achievements. This paper presents selected numerical and experimental results. From HZDR results of electron transport simulations in their new SRF gun II cavity, super-conductive solenoid and downstream accelerators are shown. The results from optimization studies into asymmetric grating structures obtained at the University of Liverpool are also presented, along with initial results from studies into novel diagnostics for high intensity proton beams at CERN and low energy electron beams at KIT. Finally, the events organized by the consortium to date and future plans are summarized.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME056

Export •

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

TUPME058

The Argonne Wakefield Accelerator (AWA): Commissioning and Operation

wakefield, gun, laser, experiment

1503

M.E. Conde, S.P. Antipov, D.S. Doran, W. Gai, C.-J. Jing, C. Li, W. Liu, J.G. Power, J.Q. Qiu, J.H. Shao, C. Whiteford, E.E. Wisniewski
ANL, Argonne, Illinois, USA
S.P. Antipov, C.-J. Jing, J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA
S. Cao
IMP, Lanzhou, People's Republic of China
C. Li, J.H. Shao
TUB, Beijing, People's Republic of China
E.E. Wisniewski
Illinois Institute of Technology, Chicago, Illinois, USA

Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-06CH11357.
The commissioning of the upgraded AWA facility is well underway. The new L-band electron gun has been fully commissioned and has been successfully operated with its Cesium Telluride photocathode at a gradient of 80 MV/m. Single bunches of up to 100 nC, and bunch trains of four bunches with up to 80 nC per bunch have been generated. The six new accelerating cavities (L-band, seven cells, pi mode) have been RF conditioned to 12 MW or more; their operation at 10 MW brings the beam energy up to 75 MeV. Measurements of the beam parameters are presently underway, and the use of this intense beam to drive high gradient wakefields will soon follow. One of the main goals of the facility is to generate RF pulses with GW power levels, corresponding to accelerating gradients of hundreds of MV/m and energy gains on the order of 100 MeV per structure.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME058

Export •

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

TUPME060

Simulation Analysis on Micro-Bunched Density Modulation from a Slit-Masked Chicane

simulation, bunching, acceleration, dipole

1509

Y.-M. Shin, P. Piot, C.R. Prokop
Northern Illinois University, DeKalb, Illinois, USA
D.R. Broemmelsiek, E.R. Harms, A.H. Lumpkin, J. Ruan, J.C.T. Thangaraj
Fermilab, Batavia, Illinois, USA

Funding: This work was supported by the DOE contract No. DEAC02-07CH11359 to the Fermi Research Alliance LLC.
Pre-bunching a beam at a resonance condition with an accelerating structure vastly improves performance of beam-driven accelerators and undulators since it enhances a beam-wave coupling. We plan to test a slit-mask micro-buncher at the chicane of Fermilab-ASTA 50 MeV beamline in the effort of advanced accelerator research. With the chicane design parameters (bending angle (alpha) of 18 degree, R56 ~ - 0.18 m, and bending radius of ~ 0.78 m), analytic model showed that a slit-mask with W (period) = 900 um and a (aperture width) = 300 um (30 % transparency) generates 100 um spaced micro-bunches with 5 ~ 6 % correlated energy spread. Two kinds of combined beamline simulation, CST-PS+Impact-Z and Elegant+Shower, including space charge and CSR effects, showed that a 900 um spaced, 300 um wide slits placed in the middle of chicane splits 20 pC – 1 nC bunches into ~ 100 um spaced micro-bunches. It is possible that a further optimization of mask design creates sub-100 fs micro-bunches, which is currently under development.
*[1] NIM A 375, 597 (1996)
[2] PRL 101, 054801 (2008)
[3] Y.-E Sun, P. R. G. Piot, FEMILAB-CONF-08-408-APC
** ASTA: Advanced Superconducting Test Accelerator

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME060

Export •

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

TUPME061

Ultra-High Gradient Beam-Driven Channeling Acceleration in Hollow Crystalline Media

acceleration, plasma, target, scattering

1512

Y.-M. Shin, T. Xu
Northern Illinois University, DeKalb, Illinois, USA
G. Flanagan
Muons, Inc, Illinois, USA
E.R. Harms, J. Ruan, V.D. Shiltsev
Fermilab, Batavia, Illinois, USA

Since the recent discovery of the Higgs boson particle, there is an increasing demand in Energy Frontier to develop new technology for a TeV/m range of acceleration gradient. The density of charge carriers, ~ 10²⁴ – 10²⁹ m^-3, of crystals is significantly higher than that of a plasma gas, and correspondingly in principle wakefield gradients of up to 0.1 - 10 TV/m are possible. Our simulations (VORPAL and CST-PIC) with Fermilab-ASTA* beam parameters showed that micro-bunched beam gains energy up to ~ 70 MeV along the 100 um long channel under the resonant coupling condition of the plasma wavelength, ~ 10 um. Also, with lowering a charge, electron bunches channeling through a high-density plasma medium have higher energy gain in a hollow channel than in a uniformly filled cylinder, which might be attribute to lower scattering ratios of the tunnel structure. The numerical analysis implied that synthetic crystalline plasma media (e.g. carbon nanotubes) have potential to mitigate constraint of bunch charges required for beam-driven acceleration in high density plasma media. The channeling acceleration** will be tested at the ASTA facility, once fully commissioned.
* ASTA: Advanced Superconducting Test Accelerator
** [1] T. Tajima and M. Cavenago, PRL 59, 13(1987)
[2] P. Chen and R. Noble, SLAC-PUB-7402(1998)
[3] V.Shiltsev, Physics Uspekhi 55, 965(2012)

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME061

Export •

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

TUPME069

Proton Electron Accelerator at CERN

plasma, proton, wakefield, experiment

1519

R. Tarkeshian
MPI, Muenchen, Germany

AWAKE is a proton driven plasma-wakefield acceleration at CERN*, that uses long proton bunches ~ 400 ps from the SPS. In a dense plasma, a long proton bunch is subject toμbunching at plasma period due to the self-modulation instability, SMI**. The self-modulated proton bunch generates large amplitude charge separation through resonant wakefield excitation. Numerical simulations show that when seeded the SMI can grow and saturate over ~4 m in a plasma with density in the (1-10) *10¹⁴/cc range. Seeding also allows for deterministic injection of witness bunches in the focusing and accelerating phase of the wakefields. The SPS proton bunch carrying kJ of energy is a unique driver for generation of ~ GeV/m wakefields through 10’s of meters of plasma. The side-injected electrons ~15 MeV can reach GeV energies. The AWAKE experimental layout, the physics of self-modulation, simulation results, plasma source under study, diagnostics plan for bunch modulation measurement using transverse coherent transition radiation***, and phasing of the witness bunch respect to the wave and synchronisation with diagnostics will be presented.****
*A. Caldwel, et. al, Nature Physics 5, 2009
**N. Kumar, A. Pukhov, PRL, 104, 2010
***O. Reimann, R. Tarkeshian, Proc. of IBIC, 2013
**** The work is submitted on behalf of AWAKE collaboration.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME069

Export •

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

TUPME073

A Novel Laser Ionized Rb Plasma Source for Plasma Wakefield Accelerators

plasma, laser, wakefield, proton

1522

E. Öz, F. Batsch, P. Muggli
MPI-P, München, Germany

Funding: AWAKE collaboration
A proton driven plasma wakefield accelerator* is to be conducted at CERN by the AWAKE collaboration. Externally injected electrons are accelerated in a large gradient (~GeV/m) wakefield. The large gradient is achieved by resonant formation of the wakefield by a train of micro-bunches. Transverse modulation of a long (~12 cm) proton bunch by the self modulation instability** creates these plasma wavelength size (~1 mm) micro-bunches. This resonant mechanism brings a strict requirement on the plasma density uniformity, namely % 0.2, in order for the injected electron bunch to remain in the accelerating and focusing phase of the wakefields. We describe the plasma source*** that satisfies this requirement during the beam plasma interaction. Rb vapor with ~10¹⁵ cm^-3 density is confined in a 10 m long 4 cm diameter, stainless-steel tube which is heated to ~200 Co by an oil heat exchanger. The access to the source during interaction is provided by custom built fast valves. The vapor is fully tunnel ionized (first e-) by a laser forming a 2 mm diameter plasma channel.
* http://awake.web.cern.ch/awake/
** http://link.aps.org/doi/10.1103/PhysRevLett.104.255003
*** http://dx.doi.org/10.1016/j.nima.2013.10.093

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME073

Export •

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

TUPME074

First Experiences with the PITZ Plasma Cell for Electron Beam Self-modulation Studies

plasma, experiment, proton, Windows

1525

M. Groß, A. Donat, J.D. Good, M. Khojoyan, G. Koss, M. Krasilnikov, R. Schütze, F. Stephan, G. Vashchenko
DESY Zeuthen, Zeuthen, Germany
R. Brinkmann
DESY, Hamburg, Germany
F.J. Grüner, G. Pathak
Uni HH, Hamburg, Germany
P. Muggli, E. Öz
MPI-P, München, Germany
D. Richter
HZB, Berlin, Germany
C.B. Schroeder
LBNL, Berkeley, California, USA

The self-modulation of long particle beams in a plasma has recently gained interest in light of the ongoing preparation for the plasma wakefield acceleration experiment of the AWAKE collaboration at CERN. Instrumental to the experiment is the self-modulation of a proton beam to generate bunches short enough for producing high acceleration fields. As electron bunches are easier to handle and the underlying physics is identical, it is judicious to first gain insight into the experimental conditions of the self-modulation of long particle beams in plasma by using electron bunches before progressing to the experiment with proton bunches. The experimental demonstration of self-modulation of an electron bunch is in preparation at the Photo Injector Test facility at DESY, location Zeuthen (PITZ). In this contribution the fabrication and first experimental tests towards a Lithium plasma cell are highlighted. The distinctive feature of this plasma cell is the addition of side ports for insertion of the ionization laser beam and for diagnostics purposes.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME074

Export •

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

TUPME075

Simulations on Laser Wakefield Generation in a Parabolic Magnetic-plasma Channel

plasma, laser, wakefield, simulation

1528

D.N. Gupta, M. Singh
University of Delhi, Delhi, India
D. Jang, H. Suk
APRI-GIST, Gwangju, Republic of Korea
B.S. Sharma
Kota University, Rajasthan, India

To utilize the laser-plasma channel for laser wakefield acceleration, we have studied the non-paraxial theory of nonlinear propagation of ultra-intense relativistic Gaussian laser pulse in a preformed spatially tapered magneto-plasma channel having a parabolic density profile. A three-dimensional envelope equation for the laser field is derived, which includes the non-paraxial and applied magnetic field effects. An analytical expression for the wakefield is derived and analyzed the results with the help of particle-in-cell (PIC) simulations. It is shown that wakefield structures and the phase of axial component of the wakefield depend on applied external magnetic field. This aspect of theoretical observation can be used in the production of highly collimated mono-energetic x-rays.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME075

Export •

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

TUPME076

Numerical modeling of the E-209 self-modulation experiment at SLAC - FACET

plasma, wakefield, simulation, experiment

1531

L.D. Amorim, L.O. Silva, J. Vieira
IPFN, Lisbon, Portugal
P. Muggli
MPI, Muenchen, Germany

The E-209 experiment currently running at SLAC- FACET used a long electron bunch (∼ 5 times the plasma wavelength) to drive plasma wakefields through the self- modulation instability. In this work we present and analyze numerical simulation results performed with the particle-in- cell (PIC) code OSIRIS. The results show that SMI saturates after 5cm of propagation in the plasma and that the maxi- mum acceleration wakefields, 15 − 20GV/m, are sustained over a 1m long plasma. Electron bunch energy loss of 4GeV was observed in the simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME076

Export •

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

TUPME077

The Challenge of Interfacing the Primary Beam Lines for the AWAKE Project at CERN

proton, plasma, laser, injection

1534

C. Bracco, B. Goddard, E. Gschwendtner, M. Meddahi, A.V. Petrenko
CERN, Geneva, Switzerland
P. Muggli
MPI, Muenchen, Germany
F.M. Velotti
EPFL, Lausanne, Switzerland

The Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) at CERN foresees the simultaneous operation of a proton, a laser and an electron beam. The first stage of the experiment will consist in proving the self-modulation, in the plasma, of a long proton bunch into micro-bunches. The success of this experiment requires an almost perfect concentricity of the proton and laser beams, over the full length of the plasma cell. The complexity of integrating the laser into the proton beam line and fulfilling the strict requirements in terms of pointing precision of the proton beam at the plasma cell are described. The second stage of the experiment foresees also the injection of electron bunches to probe the accelerating wakefields driven by the proton beam. Studies were performed to evaluate the possibility of injecting the electron beam parallel and with an offset to the proton beam axis. This option would imply that protons and electrons will have to share the last few meters of a common beam line. Issues and possible solutions for this case are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME077

Export •

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

TUPME078

Electron Injection Studies for the AWAKE Experiment at CERN

plasma, proton, wakefield, injection

1537

A.V. Petrenko, C. Bracco, E. Gschwendtner
CERN, Geneva, Switzerland
K.V. Lotov
NSU, Novosibirsk, Russia
K.V. Lotov
BINP SB RAS, Novosibirsk, Russia
P. Muggli
MPI, Muenchen, Germany

The AWAKE experiment recently approved at CERN will use the self-modulation instability (SMI) of long (12 cm), relativistic (400 GeV/c) proton bunches in dense plasmas to drive wakefields with accelerating gradients at the GV/m level. These accelerating gradients will be probed by externally injected electrons. In order to preserve the plasma uniformity required for the SMI the first experiments will use on-axis injection of a low energy 10-20 MeV electron beam collinearly with the proton beam. In this article we describe the physics of electron injection into the proton driven SMI wakefields. Requirements on the injected electron beam are determined and the final accelerated beam parameters are obtained via numerical simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME078

Export •

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

TUPME079

A Spectrometer for Proton Driven Plasma Wakefield Accelerated Electrons at AWAKE

plasma, simulation, proton, wakefield

1540

S. Jolly, L.C. Deacon, J.A. Goodhand, S.R. Mandry, M. Wing
UCL, London, United Kingdom
S.R. Mandry
MPI, Muenchen, Germany

The AWAKE experiment is to be constructed at the CERN Neutrinos to Gran Sasso facility (CNGS). This will be the first experiment to demonstrate electron acceleration by use of a proton driven plasma wakefield. The 400 GeV proton beam from the CERN SPS will excite a wakefield in a plasma cell several metres in length. To observe the plasma wakefield, electrons of a few MeV will be injected into the wakefield following the head of the proton beam. Simulations indicate that electrons will be accelerated to GeV energies by the plasma wakefield. The AWAKE spectrometer is intended to measure both the peak energy and energy spread of these accelerated electrons. The baseline design makes use of a single dipole magnet to separate the electrons from the proton beam. The dispersed electron beam then impacts on a scintillator screen: the resulting scintillation light is collected and recorded by an intensified CCD camera. The design of the spectrometer is detailed with a focus on the scintillator screen. Results of simulations to optimise the scintillator are presented, including studies of the standard GadOx scintillators commonly used for imaging electrons in plasma wakefield experiments.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME079

Export •

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

TUPME081

Plasma Wakefield Acceleration at CLARA PARS

plasma, simulation, wakefield, accelerating-gradient

1544

K. Hanahoe, O. Mete, G.X. Xia
UMAN, Manchester, United Kingdom
D. Angal-Kalinin, J.A. Clarke, J.K. Jones, J.W. McKenzie, B.L. Militsyn, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
D. Angal-Kalinin, J.A. Clarke, J.K. Jones, J.W. McKenzie, Y. Wei, C.P. Welsch, P.H. Williams
Cockcroft Institute, Warrington, Cheshire, United Kingdom
B. Hidding
USTRAT/SUPA, Glasgow, United Kingdom
J.D.A. Smith
TXUK, Warrington, United Kingdom
Y. Wei, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

PARS is a proposed Plasma Accelerator Research Station using the planned CLARA (Compact Linear Accelerator for Research and Applications) electron linear accelerator at Daresbury Laboratory in the UK. In this paper, two- dimensional particle-in-cell simulations based on realistic CLARA beam parameters are presented. The results show that an accelerating gradient of 2.0 GV/m can be achieved over an accelerating length of at least 13 cm. Preliminary simulation results for a two bunch scheme show an energy gain of 70% over a length of 13 cm, giving an average accelerating gradient of 1.2 GeV/m.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME081

Export •

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

TUPME084

On the Frequency Choice for the eRHIC SRF Linac

linac, SRF, cavity, HOM

1547

S.A. Belomestnykh, I. Ben-Zvi, V. Litvinenko, V. Ptitsyn, W. Xu
BNL, Upton, Long Island, New York, USA
S.A. Belomestnykh, I. Ben-Zvi, V. Litvinenko, V. Ptitsyn
Stony Brook University, Stony Brook, USA

Funding: Work is supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the US DOE.
eRHIC is a future electron-hadron collider proposed at BNL. It will collide high-intensity hadron beams from one of the existing rings of RHIC with a 50-mA electron beam from a multi-pass 10-GeV superconducting RF (SRF) Energy Recovery Linac (ERL). A novel approach to the multi-pass ERL utilizing a non-scaling FFAG was recently proposed. It has many advantages over the previous designs including significant cost savings. The current design has 11 passes in two FFAG rings. To mitigate various beam dynamics effects, it was proposed to lower RF frequency of the SRF linac from 704 MHz used in the previous design. In this paper we consider different effects driving the frequency choice of the SRF ERL and present our arguments for choosing lower RF frequency.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME084

Export •

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

TUPRI003

Simulating the Production and Eﬀects of Dark Currents in MICE Steps V and VI

cavity, solenoid, experiment, simulation

1556

C. Hunt, J. Pasternak, M.A. Uchida
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

Funding: STFC
The completion of the international Muon Ionisation Cooling Experiment (MICE) Step V will involve the construction, commissioning and use of RF cavity and Coupling Coil (RFCC) Modules. The RFCCs consist of 4 RF cavities and a solenoid magnet, and are expected to act as a source of potentially damaging electrons (dark currents) and X-rays. Ongoing work to create a high-statistics simulation of the dark current production, within RF cavities, is described. Current results predict the energy and angular spectra of emitted electrons for an RFCC, and include particle tracking, realistic field maps and ionisation energy losses in cavity windows. Individual electron emitters, parametrised by the Fowler-Nordheim equation, are used and are user-definable, allowing potential worst-case scenarios to be simulated and upper/lower limits for the total dark current to be estimated. These data are being used within the MICE Analysis and User Software (MAUS) to estimate the potential detector backgrounds and the damage that may be inflicted upon the scintillating fibre trackers.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI003

Export •

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

TUPRI004

The Design and Implementation of The Radiation Monitors for the Protection of the MICE Tracker Detectors

radiation, detector, experiment, emittance

1559

M.A. Uchida, C. Hunt, J. Pasternak
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

A radiation monitor will be required for the Muon Ionisation Cooling experiment (MICE) beyond Step IV, when the RF cavities are installed. The role of the radiation monitors will be to protect the particle tracking detectors (Trackers) from dangerous levels of RF dark currents and the as- sociated photon fluxes that could potentially be produced in the RF cavities. If such levels of radiation should occur the radiation monitor will ensure that the radiation shields (shutters) are closed thereby protecting the Tracker modules. The radiation monitor will be positioned on these radiation shields and will monitor x-rays, gamma-rays and electrons up to a few MeV. It is expected that the spectrum will peak at very low energies, since the peak voltage across the cavities is 8 MV/m and so the maximum energy that an electron could gain is 12 MeV (maximally accelerated from all four RF cavities). The design, positioning and expected sensitivity of the radiation monitors will be described here along with their readout and inclusion into the MICE interlocking systems. The schedule for the work and progress so far will also be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI004

Export •

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

TUPRI015

Transverse Emittance Compensation for the Rossendorf SRF Gun II

gun, solenoid, SRF, cavity

1582

H. Vennekate, A. Arnold, P.N. Lu, P. Murcek, J. Teichert, R. Xiang
HZDR, Dresden, Germany
T. Kamps
HZB, Berlin, Germany
P. Kneisel
JLab, Newport News, Virginia, USA

Funding: We acknowledge the support of the EU Community-Research Infrastructure Activity under the FP7 program (EuCARD-2, 312453) and of the German Federal Ministry of Education and Research grant 05K12CR1.
Superconducting RF particle sources combine the advantages of normal conducting RF sources and high duty cycle non-RF sources. The Rossendorf SRF gun was the first to demonstrate this injecting electrons into the ELBE accelerator at 13 MHz. Recently, a new 3-1/2-gun cavity has been prepared at Jefferson Lab for its use in an updated injector which is expected to increase the electron energy from 2.4 to 7.5 MeV. Along with this new cavity, a new gun cryostat has been introduced. It combines several minor updates to the setup with the installation of a superconducting solenoid right at the exit of the gun, compensating the emittance growth of the electron bunch at an early stage. The poster is going to conclude the results of the commissioning of the new cryostat including the solenoid and compare it to the prior concept using a normal conducting solenoid outside the cryostat. As it is of great importance to this subject, studies of the magnetic shielding are going to be presented as well.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI015

Export •

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

TUPRI016

First Studies on Ion Effects in the Accelerator ELSA

ion, synchrotron, feedback, quadrupole

1585

D. Sauerland, W. Hillert, M.T. Switka
ELSA, Bonn, Germany
A. Markoviḱ, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
A. Meseck
HZB, Berlin, Germany

Funding: BMBF (Federal Ministry of Education and Research)
In the ELSA stretcher ring electrons are accelerated by a fast energy ramp of 6 GeV/s to a beam energy of 3.2 GeV. The high energetic electrons ionize the residual gas molecules in the beam pipe by collisions or synchrotron radiation. The generated ions in turn accumulate inside the beam potential, causing several undesired effects such as tune shifts and beam instabilities. These effects are studied experimentally at ELSA using its full diagnostic capabilities. Both tune shifts due to beam neutralization and transversal beam-ion instabilities can be determined from the beam spectrum. Additionally the beam's transfer function can be measured using a broadband transversal kicker. In the stretcher ring at a beam energy of 1.2 GeV, a periodic beam blow-up was detected in the horizontal plane. Additional measurements of the transversal beam spectrum and ns-time resolution observations with a streak camera identified this blow-up as a coherent dipole oscillation of the beam. This horizontal instability is presumably caused by trapped ions, as there is a strong correlation with the high voltage-bias of the clearing electrodes.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI016

Export •

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

TUPRI019

Incoherent and Coherent Effects of Space Charge Limited Electron Clouds

wakefield, simulation, space-charge, dipole

1594

F.B. Petrov, O. Boine-Frankenheim, O.S. Haas
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: Work is supported by the BMBF under contract 05H12RD7.
Recent studies show that the space charge limited (saturated) electron cloud generated by relativistic bunches has strongly inhomogeneous distribution. In particular, a dense electron sheath is formed near the pipe wall. This feature modifies the stopping powers and the microwave transmission compared with the uniform cloud case. In this paper we investigate further the influence of the space charge limited electron cloud on relativistic bunches. In particular, we focus on the incoherent tune spread and compare the results with the homogeneous cloud case. We derive analytical expressions governing the pinch dynamics of the saturated cloud in round geometry. The contribution of the electron cloud sheath to the wake fields is investigated as well. Findings of the analytical theory are then successfully compared with numerical particle-in-cell simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI019

Export •

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

TUPRI020

Study of Electron Cloud Effects in SuperKEKB

emittance, damping, simulation, radiation

1597

K. Ohmi, D. Zhou
KEK, Ibaraki, Japan

In SuperKEKB, high beta section exists in the interaction region. Fast head-tail instability and incoherent emittance growth due to electron cloud are enhanced in the high beta section. Especially high beta sections are located every betatron phase advance pi. Nonlinear force due to electron cloud is coherently accumulated. Incoherent eminence growth dominates.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI020

Export •

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

TUPRI028

Review of Rest Gas Interaction at Very Low Energies applied to the Extra Low ENergy Antiproton ring ELENA

scattering, antiproton, emittance, ion

1621

C. Carli, T.L. Rijoff
CERN, Geneva, Switzerland
O. Karamyshev, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
O. Karamyshev, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

The Extremely Low ENergy Antiproton ring (ELENA) is a small synchrotron equipped with an electron cooler, which shall be constructed at CERN to decelerate antiprotons to energies as low as 100 keV. Scattering of beam particles on rest gas molecules may have a detrimental effect at such low energies and leads to stringent vacuum requirements. Within this contribution scattering of the stored beam on rest gas molecules is discussed for very low beam energies. It is important to carefully distinguish between antiprotons scattered out of the acceptance and lost, and those remaining inside the aperture to avoid overestimation of emittance blow-up. Furthermore, many antiprotons do not interact at all during the time they are stored in ELENA and hence this is not a multiple scattering process

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI028

Export •

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

TUPRI034

Numerical Modeling for CesrTA Measurements of Electron Cloud Buildup in a Quadrupole Magnet

detector, vacuum, quadrupole, positron

1632

J.A. Crittenden, M.G. Billing, W. Hartung, C. Shill, J.P. Sikora, K.G. Sonnad
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Work supported by the U.S. National Science Foundation contracts PHY-0734867, PHY-1002467, and the U.S. Department of Energy contract DE-FC02-08ER41538
We describe a numerical model for measurements of the formation of long-lived electron clouds in a quadrupole magnet in the CESR storage ring. The shielded stripline detector measures the electron flux incident on the vacuum chamber wall directly in front of one of the poles of the magnet. The model includes photo-electron production by synchrotron radiation, electrostatic forces from the bunched positron beam and the cloud, macroparticle tracking in the field of the quadrupole, secondary electron emission from the 9.5-cm-diameter cylindrical stainless steel beam-pipe and an analytic calculation of the transmission function of the holes in the vacuum chamber which allow cloud electrons to reach the stripline collector. These modeling studies provide a quantitative understanding of the trapping mechanism which results in cloud electrons surviving the 2.3-microsecond time interval prior to the return of a train of positron bunches. These studies have been performed in the context of the CESR Test Accelerator program, which aims to quantify and mitigate performance limitations on future low-emittance storage and damping rings.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI034

Export •

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

TUPRI035

Measurement of Beam Size in Intrabeam Scattering Dominated Beams at Various Energies at CesrTA

emittance, scattering, storage-ring, photon

1635

M. P. Ehrlichman, K.J. Blaser, A. Chatterjee, W. Hartung, B.K. Heltsley, D.P. Peterson, D. L. Rubin, D. Sagan, J.P. Shanks, S. Wang
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This research was supported by NSF and DOE contracts PHY-0734867, PHY-1002467, PHYS-1068662, DE-FC02-08ER41538, DE-SC0006505.
Recent reports from CesrTA have shown measurement and calculation of beam size versus current in CesrTA beams at 2.1 GeV. Here, the effect of changing the energy of IBS-dominated beams is reported. IBS growth rates have roughly a γ^-3 dependence. Measurements at 1.8, 2.1, 2.3, and 2.5 GeV are shown and compared with predictions from IBS theory.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI035

Export •

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

TUPRI036

Fast Ion Instability at CESR-TA

feedback, vacuum, ion, simulation

1638

A. Chatterjee, K.J. Blaser, M. P. Ehrlichman, D. L. Rubin, J.P. Shanks
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Work supported by NSF and DOE Contracts No. PHY-0734867, No. PHY-1002467, No. PHYS-1068662, No. DE-FC02-08ER41538, No. DE-SC0006505, and the Japan/U.S. Cooperation Program.
Fast Ion Instability can lead to deterioration of an electron beam (increasing emittance and instability of a train of bunches) in storage rings and linacs. We study this at the Cornell Electron Storage Ring Test Accelerator using a 2.1 GeV low emittance beam. As the source of ions is residual gas, our measurements are conducted at various pressures, including nominal vacuum as well as injected gas (Ar, Kr). We measure turn-by-turn vertical bunch size and position, as well as the multi-bunch power spectrum. A detailed simulation is then used to compare theory with observations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI036

Export •

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

TUPRI039

Radiation Safety Considerations for Areal Electron Linac With Beam Diagnostic System

radiation, shielding, target, diagnostics

1647

V.G. Khachatryan, V.H. Petrosyan, A. Sargsyan
CANDLE SRI, Yerevan, Armenia

The AREAL linear accelerator will produce electron beam with 5 MeV energy and further upgrade up to 20 MeV. At the first stage of the operation the construction of the beam diagnostic section of complex shape and layout is planned thus making the radiation source definition difficult. FLUKA particle tracking simulation code was used to calculate produced radiation dose rates and define an appropriate radiation shielding.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI039

Export •

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

TUPRI042

Numerical Study of the Microbunching Instability at UVSOR-III: Influence of the Resistive and Inductive Impedances

impedance, wakefield, synchrotron, simulation

1656

E. Roussel, S. Bielawski, C. Evain, C. Szwaj
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
M. Adachi, M. Katoh, S.I. Kimura, T. Konomi
UVSOR, Okazaki, Japan
M. Hosaka, Y. Takashima, N. Yamamoto
Nagoya University, Nagoya, Japan
K.S. Ilin, J. Raasch, A. Scheuring, M. Siegel, P. Thoma
KIT, Karlsruhe, Germany
H. Zen
Kyoto University, Kyoto, Japan

At high charge, relativistic electron bunches circulating in storage rings undergo an instability, the so-called microbunching or the CSR (Coherent Synchrotron Radiation) instability. This instability is due to the interaction of the electrons with their own radiation and leads to the formation of microstructures (at millimeter scale) in the longitudinal phase space. Thanks to a new type of detector, based on superconducting thin film YBCO, it is now possible to observe directly these microstructures and follow their temporal evolution*. These experimental observations open a new way to make severe comparisons with theory. Here we present results of the modeling of the dynamics at UVSOR-III using a one dimensional Vlasov-Fokker-Planck equation. We show that to obtain a relatively good agreement between numerical simulations and experiments, we have to take into account several types of impedance such as the shielded CSR impedance but also the resistive and inductive impedances.
* First Direct, Real Time, Recording of the CSR Pulses Emitted During the Microbunching Instability, using Thin Film YBCO Detectors at UVSOR-III, IPAC2014

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI042

Export •

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

TUPRI044

Investigation of Microbunching-instability in BERLinPro

simulation, linac, space-charge, emittance

1662

S.D. Rädel, A. Jankowiak, A. Meseck
HZB, Berlin, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association
BERLinPro is using the new energy recovery linac technology. As, maintaining the low emittance and energy spread is of major importance in an ERL, the deep understanding and control of effects which can degrade the emittance and energy spread such as space charge effects are of interest. The microbunching caused by the longitudinal space charge forces can lead to an increase in emittance and energy spread in the arcs of the loop. In this contribution, the impacts of the microbunching instability on the beam quality and its implication for BERLinPro are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI044

Export •

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

TUPRI046

Dynamics of Ion Distributions in Beam Guiding Magnets

ion, quadrupole, simulation, space-charge

1668

A. Markoviḱ, G. Pöplau, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
W. Hillert, D. Sauerland
ELSA, Bonn, Germany
A. Meseck
HZB, Berlin, Germany

Funding: Supported by the German Federal Ministry of Education and Research (BMBF) under contract number 05K13HRC.
Ions generated by synchrotron radiation and collisions of the beam with the rest gas in the vacuum chamber could be a limiting factor for the operation of electron storage rings and Energy Recovery Linacs (ERL). In order to develop beam instability mitigation strategies, a deeper understanding of the ion-cloud behaviour is needed. Numerical simulations of the interaction between electron beams and parasitic ions verified with dedicated measurements can help to acquire that knowledge. This paper presents results of detailed simulations of the interaction in quadrupole magnets and drift sections of the Electron Stretcher Accelerator ELSA in Bonn. The focus is on the evaluation of the dynamics of different ion species and their characteristic distribution in quadrupole magnets.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI046

Export •

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

TUPRI048

A Map Approach for Electron Cloud Density in a Strong LHC Dipole

simulation, dipole, space-charge, collider

1674

S. Petracca, A. Stabile
U. Sannio, Benevento, Italy
A. Stabile
INFN-Salerno, Baronissi, Salerno, Italy

The luminosity is limited by the electron cloud effects in presently running and proposed future storage rings. The evolution of the electron density during the electron cloud formation can be reproduced using a bunch-to-bunch iterative map formalism. By performing simulation codes this approach has been used to obtain a numerical prediction of the coefficients in the map, while in the presence of a magnetic field an analytic formula has been obtained for the linear coefficient. The next goal is finding a theoretical prescription of the quadratic coefficient at least in the presence of magnetic dipole. Then it will be possible to reproduce, by using the map formalism, the dynamics of electron cloud without performing the simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI048

Export •

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

TUPRI050

Numerical Calculation and Experiment of Ion Related Phenomenon in SPring-8 Storage Ring

ion, simulation, storage-ring, experiment

1680

A. Mochihashi, M. Takao
JASRI/SPring-8, Hyogo-ken, Japan

In the SPring-8 storage ring, various kinds of bunch filling pattern are available. Under some bunch filling patterns, residual gas ions created by scattering process between high energy electrons and residual gas molecules can be trapped stably around the electron beam and disturb the original motion of the beam. We have considered the stability of the electron beam due to the ion related phenomenon under several bunch filling patterns by computer simulation. In the simulation, we have modeled the electron bunch as single particle and the residual gas ions as macroparticles. The number of the trapped ions, size of the ion cloud and change in betatron oscillation amplitude of the beam under several filling pattern conditions will be discussed. We have also performed experiments for stability of the beam under equally spaced bunch filling patterns which give severe condition for the ion related instability. The numerical calculations and the experimental results will be discussed in the presentation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI050

Export •

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

TUPRI061

Power Loss Calculation in Separated and Common Beam Chambers of the LHC

impedance, coupling, simulation, cryogenics

1711

C. Zannini, G. Iadarola, G. Rumolo
CERN, Geneva, Switzerland
G. Iadarola
Naples University Federico II, Science and Technology Pole, Napoli, Italy

The performance of 25 ns beams in the LHC is strongly limited by the electron cloud. To determine the amount electron cloud in the cold sections of the machine, it is very important to be able to disentangle the beam induced heating due to the beam coupling impedance from that attributable to electron cloud. This paper will focus on the calculation of the first contribution. First, the impedance model used for the calculation of the beam induced power loss is briefly discussed. Then, the methods for the calculation of the beam induced power loss in regions with one or two beams are also described. Finally, the calculated power loss is compared with the measured heat loads for both 25 and 50 ns beams in both the LHC arcs and in the inner triplets (ITs).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI061

Export •

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

TUPRI067

Recent Results for the Dependence of Beam Instabilities caused by Electron Clouds at CesrTA due to Variations in Bunch Spacing and Chromaticity

positron, damping, feedback, controls

1721

M.G. Billing, K.R. Butler, G. Dugan, M.J. Forster, G. Ramirez, N.T. Rider, K.G. Sonnad, H.A. Williams
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J.W. Flanagan
KEK, Ibaraki, Japan
R. Holtzapple, K.E. McArdle, M.I. Miller, M.M. Totten
CalPoly, San Luis Obispo, California, USA

Funding: Work supported by DOE Award DE-FC02-08ER41538, NSF Award PHY-0734867, PHY-1068662 and the Lepton Collider R&D, Coop Agreement: NSF Award PHY-1002467
At the Cornell Electron-Positron Storage Ring Test Accelerator (CesrTA) experiments have been studying the interaction of the electron cloud (EC) with 2.1 GeV stored electron and positron beams. These experiments are intended to characterize the dependence of beam–EC interactions on various beam parameters, such as bunch spacing and vertical chromaticity. Most experiments were performed with 30 or 45-bunch trains, at a fixed current of 0.75 mA/bunch. Earlier experiments with positrons had varied the bunch spacing between 4 and 56 ns at three different vertical chromaticity settings. More recent measurements have included electron-bunch trains to contrast the build up of EC between electron and positron beams. The dynamics of the stored beam was quantified using: a gated Beam Position Monitor (BPM) and spectrum analyzer to measure the frequency spectrum of bunches in the trains; an x-ray beam size monitor to record the bunch-by-bunch, turn-by-turn vertical size of each bunch within the trains. We report on recent ob-servations from these experiments and additional studies, using witness bunches trailing 30 or 45-bunch positron trains, which were used for the generation of the ECs.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI067

Export •

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

TUPRI075

Beam Orbit Stability at Elettra

feedback, injection, storage-ring, operation

1742

G. Gaio, S. Cleva, E. Karantzoulis, S. Krecic, M. Lonza
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

The top-up operation established since 2010 at the Elettra third-generation synchrotron light source has solved the problems related to thermal drifts and beam current dependence, and a series of feedback loops acting on the machine optics and radio-frequency systems made easier to setup and operate the ring. Those systems together with the fast orbit feedback in operation since 2007, contributed to a very high electron beam orbit stability. A description of the active systems and their performance, future perspectives as well as some still open issues will be presented and discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI075

Export •

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

TUPRI077

Stabilization of Mid-infrared FEL by Feedback Controls

FEL, feedback, klystron, gun

1745

H. Zen, M. Inukai, T. Kii, K. Masuda, M. Mishima, H. Negm, H. Ohgaki, K. Okumura, K. Takami, K. Torgasin, Y. Tsugamura, K. Yoshida
Kyoto University, Kyoto, Japan

A Mid-Infrared Free Electron Laser facility, KU-FEL* has been developed for energy related sciences. A beam position monitor and feedback system was introduced to stabilize the FEL output power and wavelength. The long term stability of FEL power and wavelength has been drastically improved by the feedback control. The developed feedback system and its performance will be reported in the conference.
*H. Zen, et al., Infrared Physics & Technology, vol.51, 382-385.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI077

Export •

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

TUPRI086

Feedback System Design Techniques for Control of Intra-bunch Instabilities at the SPS

feedback, controls, damping, optics

1769

C.H. Rivetta, J.M. Cesaratto, J.E. Dusatko, J.D. Fox, O. Turgut
SLAC, Menlo Park, California, USA
W. Höfle, G. Kotzian, K.S.B. Li
CERN, Geneva, Switzerland

Funding: Work supported by the U.S. Department of Energy under contract # DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP).
The feedback control of intra-bunch instabilities driven by electron-clouds or strong head-tail coupling requires bandwidth sufficient to sense the vertical position and apply multiple corrections within a nanosecond-scale bunch. These requirements impose challenges and limits in the design and implementation of the feedback system. This paper presents model-based design techniques for feedback systems to address the stabilization of the transverse bunch dynamics. These techniques include in the design the effect of noise and signals perturbing the bunch motion. Different controllers are compared based on stability margins and equivalent noise gain between input-output of the processing channel. The controller design uses as example the bunch dynamics defined by the SPS ring including the Q20 optics.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI086

Export •

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

TUPRI097

Radiation Protection Concepts for the Beamline for Detector Tests at ELSA

radiation, simulation, neutron, detector

1799

N. Heurich, F. Frommberger, P. Hänisch, W. Hillert
ELSA, Bonn, Germany

At the electron accelerator ELSA, a new external beamline is under construction, whose task is to provide a primary electron beam for detector tests. In the future the accelerator facility will not only be offering an electron beam to the currently implemented photoproduction experiments for hadron physics, but to the new "‘research and technology center detector physics"',whose task is to develop detectors for particle and astroparticle physics. To dump and simultaneously measure the current of the electron beam behind the detector components a Faraday cup consisting of depleted uranium is used. The residual radiation leaving the cup is absorbed in a concrete casing. The radiation protection concept for the entire area of the new beamline was designed with the help of the Monte Carlo simulation program Fluka. In addition the concrete casing, radiation protection walls were taken into account to allow a safe working environment in the room created by the shielding walls. The presentation gives an overview of the different radiation protection concepts for the new beamline for detector tests at ELSA. Furthermore, progresses at the beamline will be reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI097

Export •

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

TUPRI098

The New PLC based Radiation Safety Interlock System at S-DALINAC

radiation, operation, linac, status

1802

M. Arnold, J. Birkhan, M. Brunken, J. Conrad, M. Hess, F. Hug, N. Pietralla, S.T. Sievers, P. von Neumann-Cosel
TU Darmstadt, Darmstadt, Germany

Funding: Supported by a HGS-HIRe travel grant
The Superconducting Darmstadt Linear Electron Accelerator S-DALINAC has been running since 1991. It consists of an injector linac, a main linac with two recirculations and is mainly used for in-house nuclear physics experiments as well as accelerator physics and technology. Radiation safety regulations demand an interlock system during operation of the accelerator. Amongst other major projects increasing the versatility and operation stability of the S-DALINAC, the existing, hardware based, interlock system is going to be replaced in the next shutdown period. The new interlock system is based on a PLC (Programmable Logic Controller) and will provide two subsystems, a personnel interlock system as well as a machine safety interlock system. Whereas the first subsystem is to protect staff and visitors from being harmed by ionizing radiation, the latter subsystem prohibits the S-DALINAC beam transport and vacuum elements from being damaged due to malfunctioning of any components during accelerator operation. This contribution will give an overview on this new system and will show the latest status.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI098

Export •

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

TUPRI100

Present Status of the Cherenkov Beam Loss Monitor at SACLA

undulator, detector, status, laser

1808

T. Itoga
JASRI/SPring-8, Hyogo, Japan
Y. Asano
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan

Since 2011, high power lasers have been delivered stably to the users at SACLA, the SPring-8 Angstrom compact free electron laser, and the upgrades have been performing to obtain the high quality of the laser continuously. Optical fiber based Cherenkov beam loss monitors have been successfully operated from the commissioning phase. This monitor covers the undulator section of beam lines and the electron beam transporting tunnel from SACLA to SPring-8. This monitor is made good use of not only beam transport but also detection of the small beam loss such as electron halos hitting the magnets of undulator. In this presentation, we will report the present status of the Cherenkov beam loss monitor and its usage experience.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI100

Export •

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

TUPRI104

A Beam Arrival Time Cavity for REGAE at DESY

cavity, coupling, gun, operation

1820

M. Hansli, A. Angelovski, R. Jakoby, A. Penirschke
TU Darmstadt, Darmstadt, Germany
K. Flöttmann, D. Lipka, H. Schlarb, S. Vilcins
DESY, Hamburg, Germany
F.J. Grüner, B. Zeitler
CFEL, Hamburg, Germany

Funding: Kindly funded by BMBF within FSP302.
REGAE (Relativistic Electron Gun for Atomic Exploration) at DESY in Hamburg is a linear accelerator for electron diffraction experiments. It is upgraded to allow for laser driven wake field accelerator experiments. The bunch length is around 10 fs and the wakefield structure is about 100 fs and the synchronization of the laser and the electron bunch needs to be in order of the bunch length. To achieve this, a RFbased scheme will be used, comparing the phase of a beam induced signal with the reference clock. To improve the performance for the operation with charges well below 1 pC a beam arrival time cavity (BAC) at 3.025 GHz is foreseen as a highly sensitive pickup. To provide the maximum energy to the measurement electronics, the cavity needs a high R=Qvalue and an optimized coupling. An over-coupled setting might be beneficial as it provides a higher signal-to-noise ratio for the first samples. In this paper the concept of the beam arrival time cavity, the influence of the dark current on the measurement and parameter studies and optimization of the cavity itself are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI104

Export •

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

TUPRI108

Development of New Tag Supply System for DAQ for SACLA User Experiments

experiment, laser, controls, free-electron-laser

1826

T. Abe
RIKEN SPring-8 Center, Innovative Light Sources Division, Hyogo, Japan
A. Amselem, K. Okada, R. Tanaka, M. Yamaga
JASRI/SPring-8, Hyogo-ken, Japan

This paper presents development of a new tag supply system for the data-acquisition (DAQ) system for SACLA user experiments. The X-ray Free-Electron Laser facility in SPring-8, SACLA, has delivered X-ray laser beams to users since March 2012 [1]. For the user experiments at SACLA, a dedicated DAQ system has been developed. The DAQ system is currently capable to operate with maximum ten sensors of multiport Charge-Coupled Device (MPCCD) for X-ray detection. The data of ten sensors are read out with individual readout modules. We implement a new tag supply system to ensure the reconstruction of the diffraction image of the user experiments. The tag data are used to synchronize the data. One master server receives a signal given by accelerator and the delivery of the tag data follows to five experimental halls at SACLA and some of monitors at SACLA accelerator. We employ dedicated communication lines to deliver the tag data. The longest distance to deliver the tag data is about one kilometer. We need to update entire softwares of DAQ system for the implementation. We will implement the new system to the DAQ system by the spring 2014.
[1] T. Ishikawa et al., "A compact X-ray free-electron laser emitting
in the sub-angstrom region", Nature Photonics 6, 540-544 (2012).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI108

Export •

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

WEOAA01

Longitudinal Top-up Injection for Small Aperture Storage Rings

injection, kicker, storage-ring, radiation

1842

M. Aiba, M. Böge, F. Marcellini, A. Saá Hernández, A. Streun
PSI, Villigen PSI, Switzerland

Future light sources aim at achieving a diffraction limited photon beam both in the horizontal and vertical planes. Small magnet apertures and high magnet gradients of a corresponding ultra-low emittance lattice may restrict physical and dynamic acceptance of the storage ring such that off-axis injection and accumulation may become impossible. We investigate a longitudinal injection, i.e. injecting an electron bunch onto the closed orbit with a time-offset with respect to the circulating bunches. The injected bunch will be merged to a circulating bunch thanks to longitudinal damping.

Slides WEOAA01 [0.953 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEOAA01

Export •

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

WEOAA02

Development of the Very Short Period Undulators

undulator, radiation, photon, vacuum

1845

S. Yamamoto
KEK, Ibaraki, Japan

We have been exploring a method to fabricate very short period undulators, a period length of which is one order-of-magnitude shorter than the ordinary period of several cm. We are developing a plate-type magnet some 100mm long with a period length of 4mm. We selected this period length since we can generate 12-keV radiation with the first harmonic of this undulator in the 2.5-GeV storage ring. A multi-pole magnetizing method was applied to magnetizing this plate: a periodic undulator field (of 4-mm period in this case) was generated by pulsed electro-magnets, and was transcribed into the plate. The magnetization procedure allows the undulator field to be obtained in a very short gap between the pair of opposing plates, which is also one order-of-magnitude shorter than a gap in the ordinary undulators. We report the magnetization method to obtain a very short period and present the test results. The calculated spectrum of the radiation from the measured field compares well with that from an ideal magnetic field in the region of the fundamental radiation in case of 2.5-GeV energy of the electron beam.

Slides WEOAA02 [5.189 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEOAA02

Export •

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

WEOAA03

Ultrashort and Coherent Radiation for Pump-probe Experiments at the DELTA Storage Ring

radiation, laser, experiment, undulator

1848

M. Huck, S. Hilbrich, H. Huck, M. Höner, S. Khan, C. Mai, A. Meyer auf der Heide, R. Molo, H. Rast, A. Schick, P. Ungelenk
DELTA, Dortmund, Germany

Funding: Work supported by DFG, BMBF, and by the Federal State NRW.
A light source facility employing the coherent harmonic generation (CHG) principle is being commissioned and operated since 2011 at DELTA, a 1.5-GeV electron storage ring at the TU Dortmund University, with the purpose of providing ultrashort coherent VUV radiation for time-resolved experiments. CHG is based on the interaction of ultrashort laser pulses with electrons in an undulator to generate coherent harmonics of the laser wavelength. Different methods have been used to optimize, detect and characterize the CHG radiation. One example is the study of transverse and longitudinal coherence properties in double-slit and Michelson experiments. Moreover, final steps towards performing pump-probe experiments to study ultrafast magnetic phenomena have been taken.

Slides WEOAA03 [4.139 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEOAA03

Export •

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

WEOAB03

Linear Electron Acceleration in THz Waveguides

linac, acceleration, laser, accelerating-gradient

1896

E.A. Nanni, W.S. Graves, K.-H. Hong, W.R. Huang, F.X. Kärtner, KR. Ravi, L.J. Wong
MIT, Cambridge, Massachusetts, USA
A. Fallahi, F.X. Kärtner
CFEL, Hamburg, Germany
R.J.D. Miller
DESY, Hamburg, Germany
G. Moriena
University of Toronto, Toronto, Ontario, Canada

Funding: Supported by DARPA N66001-11-1-4192, CFEL DESY, DOE DEFG02-10ER46745, DOE DE-FG02-08ER41532, ERC Synergy Grant 609920 and NSF DMR-1042342.
We report the first experimental demonstration of linear electron acceleration using an optically generated single cycle THz pulse centered at 0.45 THz. 7 keV of acceleration is achieved using 10 microJ THz pulses in a 3 mm interaction length. The THz pulse is produced via optical rectification of a 1.2 mJ, 1 micron laser pulse with a 1 kHz repetition rate. The THz pulse is coupled into a dielectric-loaded circular waveguide with 10 MeV/m on-axis accelerating gradient. A 25 fC input electron bunch is produced with a 60 keV DC photo-emitting cathode. The achievable accelerating gradient in the THz structures being investigated will scale rapidly by increasing the IR pulse energy (100 mJ - 1 J) and correspondingly the THz pulse energy. Additionally, with recent advances in the generation of THz pulses via optical rectification, in particular improvements to efficiency and generation of multi-cycle pulses, GeV/m accelerating gradients could be achieved. An ultra-compact high-gradient THz accelerator would be of interest for a wide variety of applications.

Slides WEOAB03 [7.185 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEOAB03

Export •

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

WEOBB02

Status of Single-shot EOSD Measurement at ANKA

laser, wakefield, operation, storage-ring

1909

N. Hiller, A. Borysenko, E. Hertle, V. Judin, B. Kehrer, S. Marsching, A.-S. Müller, M.J. Nasse, M. Schuh, P. Schönfeldt, N.J. Smale, J.L. Steinmann
KIT, Karlsruhe, Germany
P. Peier, B. Steffen
DESY, Hamburg, Germany
V. Schlott
PSI, Villigen PSI, Switzerland

Funding: This work is funded by the BMBF contract numbers: 05K10VKC, 05K13VKA.
ANKA is the first storage ring in the world with a near-field single-shot electro-optical (EO) bunch profile monitor. The method of electro-optical spectral decoding (EOSD) uses the Pockels effect to modulate the longitudinal electron bunch profile onto a long, chirped laser pulse passing through an EO crystal. The laser pulse is then analyzed with a single-shot spectrometer and from the spectral modulation, the temporal modulation can be extracted. The setup has a sub-ps resolution (granularity) and can measure down to bunch lengths of 1.5 ps RMS for bunch charges as low as 30 pC. With this setup it is possible to study longitudinal beam dynamics (e. g. microbunching) occurring during ANKA's low-alpha-operation, an operation mode with compressed bunches to generate coherent synchrotron radiation in the THz range. In addition to measuring the longitudinal bunch profile, long-ranging wake-fields trailing the electron bunch can also be studied, revealing bunch-bunch interactions.

Slides WEOBB02 [12.753 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEOBB02

Export •

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

WEPRO002

Studies of Ultrashort THz Pulses at DELTA

laser, detector, radiation, simulation

1936

P. Ungelenk, L.-G. Böttger, S. Hilbrich, H. Huck, M. Huck, M. Höner, S. Khan, C. Mai, A. Meyer auf der Heide, R. Molo, H. Rast, A. Schick
DELTA, Dortmund, Germany
S. Bielawski, C. Evain, M. Le Parquier, E. Roussel, C. Szwaj
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
N. Hiller, V. Judin, J. Raasch, P. Thoma
KIT, Karlsruhe, Germany

Funding: Work supported by the DFG, the BMBF, and the state of NRW.
At DELTA, a 1.5-GeV electron storage ring operated as a light source by the Center for Synchrotron Radiation at the TU Dortmund University, coherent ultrashort THz pulses are routinely generated by density-modulated electron bunches. Tracking simulations as well as experimental studies using ultrafast THz detectors and an FT-IR spectrometer aim at understanding the turn-by-turn evolution of the density modulation after an initial laser-electron interaction. Furthermore, intensity-modulated laser pulses are applied to create narrow-band THz radiation. This setup is part of the new short-pulse facility based on coherent harmonic generation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO002

Export •

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

WEPRO003

Construction of a Laser Compton Scattered Photon Source at cERL

photon, laser, cavity, gun

1940

R. Nagai, R. Hajima, M. Mori, T. Shizuma
JAEA, Ibaraki-ken, Japan
T. Akagi, Y. Honda, A. Kosuge, J. Urakawa
KEK, Ibaraki, Japan

A nondestructive assay system of isotopes by quasi-monochromatic gamma-rays and nuclear resonance fluorescence is under development in JAEA. The quasi-monochromatic gamma-rays are generated by laser Compton scattering (LCS) based on energy-recovery linac accelerator and laser technologies. In order to demonstrate the accelerator and laser performance required for the gamma-ray source, an LCS experiment is planned at Compact ERL (cERL) at KEK. A mode-locked fiber laser, laser enhancement cavity, beamline, and experimental hatch are under construction for the LCS experiment. Up-to-date construction status is presented in detail.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO003

Export •

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

WEPRO004

Status of Laser Compton Scattered Gamma-ray Source at JAEA 150-MeV Microtron

laser, radiation, microtron, detector

1943

R. Hajima
JAEA/ERL, Ibaraki, Japan
I. Daito, H. Negm, H. Ohgaki
Kyoto University, Kyoto, Japan
M. Ferdows, T. Hayakawa, M. Kando, T. Shizuma
JAEA, Ibaraki-ken, Japan

Funding: This work is supported by Funds for Integrated Promotion of Social System Reform and Research and Development.
We have developed a laser Compton scattered gamma-ray source based on a 150-MeV racetrack microtron at Japan Atomic Energy Agency. The microtron equipped with a photocathode RF gun accelerates a single bunch of electrons to collide with a laser pulse from a Nd:YAG laser. Such gamma-ray source realizes industrial application of nuclear material detection in a ship cargo, which is one of the urgent requests of international nuclear security. Recent status of gamma-ray generation experiments and design study of a practical machine is presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO004

Export •

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

WEPRO007

Nanometer Scale Coherent Current Modulation via a Nanotip Cathode Array and Emittance Exchange

emittance, cavity, gun, linac

1952

E.A. Nanni, W.S. Graves
MIT, Cambridge, Massachusetts, USA
P. Piot
Fermilab, Batavia, Illinois, USA
P. Piot
Northern Illinois University, DeKalb, Illinois, USA

Funding: NSF DMR-1042342, DARPA N66001-11-1-4192
We present PIC simulations of electron bunches with nm scale longitudinal modulation produced using a compact 2-20 MeV LINAC. The modulation is initially imparted in the transverse dimension of the electron bunch with a nano-patterned photo-emitter in a X-band RF gun with 2 MeV exit energy. The electron bunch passes through a 1 m standing wave X-band LINAC which can raise the beam energy up to 20 MeV. The transverse modulation is exchanged into the longitudinal dimension using a double dog-leg emittance exchange setup with a 5 cell RF deflector cavity. The modulation pitch can be tuned by adjusting the spacing of the nano-patterned photo-emitter or magnification of the transverse pitch with electron optics. The electron beam parameters are optimized to produce coherent XFEL radiation upon interacting with a “laser undulator”.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO007

Export •

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

WEPRO008

A Beam-driven Microwave Undulator for FEL

undulator, wakefield, FEL, linac

1956

A. Kanareykin, C.-J. Jing, P. Schoessow
Euclid TechLabs, LLC, Solon, Ohio, USA
S. Baturin
LETI, Saint-Petersburg, Russia
A. Zholents
ANL, Argonne, Ilinois, USA

Funding: DOE SBIR
Microwave waveguides can in principle be used for undulators with periods less than 1 cm. Intensive work has been done on the recently proposed design that operates at the HE11 hybrid mode of a corrugated waveguide; successful experimental results have been reported recently [S.Tantawi Talk at POSIPOL 2012]. In this presentation we propose a beam driven design for an undulator based on an electron bunch train powering a microwave or mm waveguide. The drive bunch train propagates towards the undulating beam inside a dielectric loaded structure or corrugated waveguide generating high power RF. The “smart” waveguide design and a proper bunch spacing of the electron drive beam train provide single mode generation of the high magnitude undulating field that gives an undulator parameter in the range of K~1 for a high frequency device.*
*A. Zholents, HBEB Workshop, Puerto-Rico, 2013.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO008

Export •

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

WEPRO011

Design Study of Pulsed Multipole Injection for Aichi SR

injection, multipole, storage-ring, power-supply

1962

N. Yamamoto, M. Hosaka, A. Mano, T. Takano, Y. Takashima
Nagoya University, Nagoya, Japan
M. Katoh
UVSOR, Okazaki, Japan

Since March of 2013 the user operation has been started with the top-up injection mode of the storage ring at Aich SR.The accelerators of Aichi SR consisted with a 50 MeV linac, an 1.2 GeV full energy booster and the storage ring. The　operation current of the storage ring is 300 mA and the injection rate is up to 1 Hz. The single bunch injection scheme is　employed and the electron beam can be injected into the arbitrary bucket of the storage ring. Up to now, the stabilitiy of 0.2 % for the stored beam current was achieved, however, the coherent oscillation of stored beams due to injection kikers is also obserbed. In order to introduce the new injection scheme into Aichi SR and to suppress that coherent oscillation, we have designed the pulsed multipole injection system. The system consists of the sextupole-like pulsed magnet and the micro-sec responce power supply. In the paper, we will report the results of beam tracking calculations with our designed magnet and power supply.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO011

Export •

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

WEPRO012

New Injection System of Siberia-2 Light Source

injection, kicker, septum, simulation

1965

S.I. Tomin, V. Korchuganov
NRC, Moscow, Russia

The storage ring Siberia-2 is SR source of second generation with circumference 124 m. The electron beam is injected into the ring at the energy 450 MeV. The Siberia-2 injection system was initially consisted of two high voltage rectangular pulses generators connected to the two in-vacuum strip – line kickers of traveling wave (wave impedance 50 Ohm) – a pre-inflector and an inflector. The amplitude voltage was 25-35 kV with 20 ns pulse duration and 2-3 ns pulse front/fall. Recently the new injection generators were proposed. Injection system now includes the same kickers and the new 1 microsecond pulse duration and 10 kV voltage amplitude generators. A dynamics of the electron beam after injection moment is considered in the article. The possibility of effective injection with kikers pulse duration over 2 periods of revolution of the electron beam is shown. The results of the new injection system commissioning are also demonstrated.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO012

Export •

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

WEPRO023

Preventing Superconducting Wiggler Quench during Beam Loss at the Canadian Light Source

wiggler, simulation, radiation, storage-ring

1992

W.A. Wurtz, L.O. Dallin, M.J. Sigrist, J.M. Vogt, M.S. de Jong
CLS, Saskatoon, Saskatchewan, Canada

The Canadian Light Source utilizes two superconducting wigglers for the production of hard x-rays. These superconducting wigglers often quench during beam loss, even though tracking calculations predict that the beam is lost on an aperture far from the wigglers. We present measurements that suggest the tracking simulations are correct and the electron beam indeed strikes the predicted limiting inboard aperture. By simulating the interaction of the beam with the aperture, we find that some scattered electrons can retain sufficient energy to remain inside the storage ring. The simulations show that some of these scattered electrons strike the wiggler vacuum chamber and deposit energy in the superconducting coils, causing the quench.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO023

Export •

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

WEPRO027

W164: A Wiggler Dedicated to the PUMA Beamline and the FEMTOSLICING Project at SOLEIL

wiggler, operation, laser, photon

1998

O. Marcouillé, H.B. Abualrob, P. Brunelle, L. Chapuis, M.-E. Couprie, T.K. El Ajjouri, M. Labat, J.L. Marlats, F. Marteau, A. Mary, A. Nadji, K. Tavakoli, M.-A. Tordeux, M. Valléau
SOLEIL, Gif-sur-Yvette, France

The W164 out-vacuum wiggler was designed and built at SOLEIL with the double goal of producing high energy photons for the PUMA beamline (10 keV to 70 keV) and to be used as a modulator for the FEMTOSLICING project. The insertion device requires simultaneously reaching low resonant energy (1.55 eV) and high critical energy of photons (above 10 keV), leading to the choice of high field and large periods. The 3.28 m long wiggler is composed of 20 periods of 164 mm made of NdFeB magnets and vanadium permendur poles. The required effective field for the FEMTOSLICING is 1.53 T and the maximum total field reaches 1.8T at the minimum gap of 14.5 mm. The small transverse size of the poles was optimized to minimize the magnetic forces (8 tons maximum) resulting, together with the large field produced at minimum gap, to a large vertical dynamic field integral (DFI) inside the horizontal physical aperture of the chamber. A dedicated permanent magnet system was designed, constructed and installed at both wiggler ends to cancel the DFI at minimum gap. The construction of the wiggler, the results of the magnetic measurements and the effects on dynamics measured on electron beam are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO027

Export •

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

WEPRO029

Developing of Advanced Magnet Structures for Cryogenic in Vacuum Permanent Magnet Undulators

undulator, permanent-magnet, cryogenics, vacuum

2004

C. Kuhn, J. Bahrdt, A. Gaupp, M. Scheer, B. Schulz
HZB, Berlin, Germany

Cryogenic in vacuum permanent magnet undulators with periods less than 10 mm and correspondingly narrow gaps require tighter geometric and magnetic tolerances and complex pole designs from different materials to achieve the needed high field strengths. We use new mechanic designs and manufacturing technologies for magnet and pole assembly. We develop new precise and UHV-compatible joining methods which are different from the current approaches which are based on mechanical clamping or gluing. . We examine the mechanical and magnetic properties by performing tests and discuss the results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO029

Export •

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

WEPRO032

Phase Shifters for the FLASH2 FEL

undulator, operation, quadrupole, FEL

2010

M. Tischer, P. Neumann, A. Schöps, P. Vagin
DESY, Hamburg, Germany

The FLASH2 SASE undulator section consists of 12 IDs. Each of them is followed by an intersection component comprising a phase shifter and various parts for diagnostics and beam steering. The phase shifter is a compact and simple electromagnetic chicane and has to assure constructive interference of the radiation of adjacent undulators for all wavelengths. The magnetic performance, field errors and the hysteresis behavior have been investigated and were found to be within the required accuracy. The results are discussed in relation to the undulator conditions. From these data tables for steering the phase shifter current as function of undulator gap were derived and implemented in the control system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO032

Export •

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

WEPRO033

Design and Magnetic Measurements on Bi-harmonic Undulators

undulator, laser, free-electron-laser, synchrotron

2013

G. Sharma, G. Mishra
Devi Ahilya University, Indore, India
S. Tripathi
DESY, Hamburg, Germany

In recent years there exists interests in harmonic lasing of free electron lasers for short wavelength operation with low energy electron beams. In a planar undulator , the electron radiates at odd harmonics on axis however the harmonic gain of the FEL is much less than that of fundamental. It has been shown in earlier works that it is possible to enhance the harmonic radiation by increasing the harmonic wiggler field to the fundamental by putting high permeability shims inside the undulator. The common material is the vanadium permendur (μ ~800) , which has been used effectively to design the harmonic undulator. In this paper, we report the design and fabrication of seventh and ninth harmonic undulator for free electron laser applications. We use CRGO shims with μ ~ 2-3. The permanent magnet undulator is a four block per period design. The undulator is a variable gap type and consists of NdFeB magnets with six periods, each period is of 5cm length. The undulator has been measured in hall probe and pulsed wire bench. It is shown that the pulsed wire magnetic measurements yields results in close agreement with hall probe results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO033

Export •

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

WEPRO036

Construction and First Magnetic Field Test of a Superconducting Transversal Gradient Undulator for the Laser Wakefield Accelerator in Jena.

undulator, laser, radiation, wakefield

2022

V. Afonso Rodríguez, A. Bernhard, A.W. Grau, P. Peiffer, R. Rossmanith, M. Weber, C. Widmann, A. Will
KIT, Karlsruhe, Germany
M. Kaluza, M. Nicolai, A. Sävert
IOQ, Jena, Germany
M. Reuter
HIJ, Jena, Germany

Funding: This work is funded by the German Federal Ministry for Education and Research under contract no. 05K10VK2 and 05K10SJ2.
A superconducting transversal gradient undulator (TGU), tailored to the particular beam properties of the laser wakefield accelerator (LWFA) at the University of Jena, has been designed and constructed at KIT. This undulator in combination with a specialized beam transport line will be employed to produce undulator radiation with natural bandwidth despite the relatively large energy spread of the electrons produced by the LWFA. The fabrication of this undulator and first results of the magnetic field measurement are discussed in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO036

Export •

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

WEPRO039

Status of PAL-XFEL Undulator Program

undulator, FEL, controls, radiation

2029

D.E. Kim, H.-S. Kang, W.W. Lee, K.-H. Park
PAL, Pohang, Kyungbuk, Republic of Korea
M.-H. Cho, I.S. Ko
POSTECH, Pohang, Kyungbuk, Republic of Korea
S. Karabekyan, J. Pflüger
XFEL. EU, Hamburg, Germany

Pohang Accelerator Laboratory (PAL) is developing 10 GeV, 0.1 nm SASE based FEL for high power, short pulse X-ray coherent photon sources named PAL-XFEL. At the first stage PAL-XFEL needs two undulator lines for photon source. PAL is developing undulator magnetic structure based on EU-XFEL design. Recently, the hard X-ray undulator changed its minimum magnetic gap to 8.3 mm from the previous 7.2 mm to alleviate the wake field impact, and to increase the allowances for the re alignment. Accordingly, the period is also changed from 24.4 mm to 26.0 mm to generate 0.1 nm at 10 GeV electron energy. In this report, the modification efforts and the progress on the prototyping of hard x-ray undulator system will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO039

Export •

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

WEPRO041

Undulator Radiation Spectral Broadening Due To Radiation Energy Loss

undulator, radiation, simulation, photon

2035

N.V. Smolyakov
NRC, Moscow, Russia

A relativistic electron passing through an undulator generates electromagnetic radiation at the expenses of its own kinetic energy. This effect is usually not taken into account if the number of periods of the undulator is relatively small (100 - 200). However, at FEL facilities, long installations have been built, planned or are under construction, where many undulators are installed one after another for a total of several thousand undulator periods. For instance, the SASE1 and SASE2 lines at the European XFEL will consist of 35 undulators with 124 periods each. In this case, because of the electron energy decrease along its trajectory, the radiation from different undulators will drop out of synchronism. As a result, the radiation spectral line will be much wider. In the presented report, this effect was analyzed analytically and numerically. An expression for the critical number of undulator periods, when the effect of electron energy loss should be properly taken into account, is derived. It is found that, for the case of the European XFEL, this number is about 1200 periods.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO041

Export •

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

WEPRO047

A New Cooling System for Cryocooled Permanent Magnet Undulators at Diamond Light Source

vacuum, undulator, operation, cryogenics

2047

E.C. Longhi, A.G. Miller, E.C.M. Rial, A.J. Rose, J.C. Schouten, C.W. Thompson, A. Thomson, J.H. Williams
DLS, Oxfordshire, United Kingdom
C. Monroe
Monroe Brothers Ltd., Moreton-in-Marsh, United Kingdom

Cryocooled permanent magnet undulators (CPMUs) using NdFeB magnets around 150K were first proposed by Hara*. These are cooled by using either GM cryocoolers or circulating sub-cooled liquid nitrogen. Due to the heat load from radiation and wakefield heating from the electron beam, temperature gradients can develop along the length of the magnet girders which could be as large as several degrees for the Diamond Light Source (DLS) storage ring operating parameters. Some grades of the magnetic material (NdxPr1-x)2Fe14B have remanence curves versus temperature which increase significantly for temperatures below 150K with peaks below 80K**. This means that the operating temperature of a CPMU using this material can be close to the boiling point of liquid nitrogen. The proposed cooling system for the new DLS CPMU is based on a thermosiphon allowing nitrogen to boil inside the cooling channels without a circulating pump. This has the advantage of absorbing large amounts (>250W) of heat with very small temperature gradients. We report here the results of a prototype magnet beam cooled with a thermosiphon producing a temperature gradient of less than 0.05K along a 2m beam at ~77K.
* T. Hara et al., Phys Rev Spec Top. Accelerator & Beam, Vol 7, 2004.
** J. Bahrdt et al., AIP Conf. Proc., SRI 2009, Melbourne Australia, vol. 1234, pp. 499-502, 2010.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO047

Export •

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

WEPRO048

A Concept of a Universal Superconducting Undulator

undulator, simulation, storage-ring, FEL

2050

Y. Ivanyushenkov
ANL, Argonne, Ilinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
Tiny round electron beams of free-electron lasers and relatively new diffraction-limited storage rings make possible utilization of electromagnetic helical undulators based on double-helical windings. It has been understood for a while that a coaxial pair of double-helical windings can generate helical as well as planar magnetic fields*. Such a coil structure can potentially be realized with superconducting windings thus forming the concept of a universal superconducting undulator (Universal SCU). An example of a possible universal SCU for the recently suggested Advanced Photon Source multi-bend achromat storage ring is given in this paper. The results of the magnetic simulation together with initial cryogenic considerations are presented.
* D.F. Alferov, Yu.A. Bashamakov, E. G. Bessonov, Sov. J. Tech. Phys. 21(11), (1976) 1408.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO048

Export •

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

WEPRO050

Cryogenically Cooled 1J, ps Yb:YAG Slab Laser for High-brightness Laser-Compton X-Ray Source

laser, photon, booster, operation

2056

A. Endo, M. Chyla, T. Miura, T. Mocek, P. Sikocinski
Czech Republic Academy of Sciences, Institute of Physics, Prague, Czech Republic
K. Sakaue, M. Washio
RISE, Tokyo, Japan

Funding: This work benefitted from the support of the Czech Republic’s Ministry of Education, Youth and Sports to the HiLASE and DPSSLasers projects cofinanced from the European Regional Development Fund.
Laser Compton X-ray source is studied as an accelerator-laser hybrid technology to realize a compact source from soft X-ray to gamma ray*. It is critical to design a solid state laser of 1J pulse energy with 1ps pulse length, and a high beam quality for 10 microμm diameter interaction. The required M2 is less than 1.5 in a standard normal incidence configuration. X-ray total photon number is ~10⁹ with 1nC, 3ps 43MeV electron bunch for each shot. HiLASE project is committed to make a progress in the field of new generation solid state laser based on Yb-doped materials, to deliver 1J at 120Hz of 1-2ps with M2<1.5. The laser system consists of a seed fiber laser and two amplifier stages, an Yb:YAG thin disk regenerative amplifier, and a cryogenically cooled single slab booster amplifier. We have obtained output energy of 45mJ from the regenerative amplifier at 1 kHz with M2 <1.2. Booster amplifier is designed by a conduction cooling to build a compact system. Gain bandwidth was 1.2nm at 120K, enough to obtain 1-2ps pulses. Improvement of the crystal holder and the experimental results are presented to indicate the available pulse energy and M2.
*Endo, A. et.al. “Characterization of the monochromatic laser Compton X-ray beam with picosecond and femtosecond pulse widths”, Proceedings SPIE 4502, pp100-108 (2001)

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO050

Export •

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

WEPRO051

Commissioning of the Laser Beam Transport for the Femto-slicing Project at the Synchrotron SOLEIL

laser, wiggler, beam-transport, diagnostics

2059

P. Prigent, M.-E. Couprie, Ph. Hollander, M. Labat, C. Laulhé, A. Lestrade, J. Lüning, J.L. Marlats, P. Morin, A. Nadji, S. Ravy, J.P. Ricaud, M.G. Silly, F. Sirotti, M.-A. Tordeux, D. Zerbib
SOLEIL, Gif-sur-Yvette, France

The aim of the Femto-Slicing project at SOLEIL is to generate 100 fs X-rays pulses on two beamlines, CRISTAL and TEMPO in a first step, for pump-probe experiments in the hard and soft X-rays regions and possibly on two other beamlines in the future. Two fs lasers are currently in operation on TEMPO and CRISTAL for pump-probe experiments on the ps time scale enabling time resolved photoemission and photodiffraction studies. The Femto-Slicing project is based on the fs laser of the CRISTAL beamline, which can be adjusted to deliver 5 to 3 mJ pulses of 30 fs duration at 1 to 2.5 kHz respectively. The laser beam is separated in three branches: one delivering about 2 mJ to the modulator Wiggler and the other ones delivering the remaining energy to the TEMPO and CRISTAL experiments. This layout will yield natural synchronization between IR laser pump and X-ray probe pulses, only affected by drift associated with beam transport. In this paper, we present the current status of the Femto-Slicing project at SOLEIL, with particular emphasis on the characterization of the laser beam transport to the wiggler, to the CRISTAL beamline, and with the first results that will be obtained.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO051

Export •

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

WEPRO053

All-optical Free Electron Lasers using Travelling-wave Thomson Scattering

laser, FEL, undulator, scattering

2065

K. Steiniger, M.H. Bussmann, A.D. Debus, A. Irman, A. Jochmann, R.G. Pausch, U. Schramm
Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany
T.E. Cowan
HZDR, Dresden, Germany

In Travelling-Wave Thomson Scattering (TWTS) the pulse front of a high-power, short-pulse laser is tilted and the dispersion of the pulse is controlled in such a way that electrons can interact over a long distance with a quasi-monochromatic electromagnetic wave. We present a complete three dimensional analytic time-dependent description of the TWTS field and use this description to derive an analytic FEL equation that shows that TWTS indeed provides for an all-optical FEL. We further derive conditions for optimum operation of the TWTS FEL, showing that EUV and XUV FEL sources are in reach using Petawatt lasers and conventional few-hundred MeV electron sources. Future laser-wakefield accelerators could potentially drive all-optical TWTS-FELs in the X-ray and beyond. TWTS itself is optimum to provide full flexibility in terms of the wavelength and bandwidth of the scattered radiation, allowing for application-optimized, highly-brilliant Thomson Scattering sources for a broad range of wavelengths from the EUV to the gamma ray spectral region.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO053

Export •

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

WEPRO055

Development of a Quasi 3-D Ellipsoidal Photo Cathode Laser System for PITZ

laser, emittance, simulation, cathode

2069

T. Rublack, M. Khojoyan, M. Krasilnikov, F. Stephan
DESY Zeuthen, Zeuthen, Germany
A.V. Andrianov, E. Gacheva, E. Khazanov, A. Poteomkin, V. Zelenogorsky
IAP/RAS, Nizhny Novgorod, Russia
I. Hartl, S. Schreiber
DESY, Hamburg, Germany
E. Syresin
JINR, Dubna, Moscow Region, Russia

Funding: Funded by the German Federal Ministry of Education and Research (BMBF) project 05K10CHE in the framework of the German-Russian collaboration "Development and Use of Accelerator-Based Photon Sources".
3-D ellipsoidal photo cathode laser pulses are considered as the next step in optimization of photo injectors required for a successful operation of linac based free electron lasers. Significant improvements in electron beam emittance obtained from the beam dynamics simulations using such laser pulses compared to the conventional cylindrical pulses motivated the experimental studies in order to develop a laser system for quasi 3-D ellipsoidal pulses. The Institute of Applied Physics (Nizhny Novgorod, Russia) in collaboration with the Joint Institute of Nuclear Research (Dubna, Russia) and the Photo Injector Test facility at DESY, Zeuthen site (PITZ) is developing such a photo cathode laser system. Experimental tests of the laser system with photoelectron beam production are planned at PITZ. The laser pulse shaping is realized using the spatial light modulator technique. The laser system is capable of pulse train generation. First cross-correlation measurements were done demonstrating in principle the ability to generate and measure quasi ellipsoidal laser pulses. In this contribution the overall set-up, working principle and the actual progress of the development will be reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO055

Export •

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

WEPRO057

Effect of the Electron Beam Emittance on the ILSF Radiation of Sources and Beamline Design

emittance, photon, undulator, brilliance

2075

A. Gholampour, S. Amiri, H. Ghasem, H. Khosroabadi, J. Rahighi
ILSF, Tehran, Iran
H. Ghasem, M. Lamehi Rashti, J. Rahighi
IPM, Tehran, Iran

At the Iranian Light Source Facility (ILSF), two different storage ring options are being studied. The designs differ in emittance. In the first option the calculated emittance is 3.278 nm-rad whereas for the second option emittance is 0.937 nm-rad. In this paper the electron beam emittance effects on the source radiation properties from bending magnet, wiggler and undulator, X-ray optics and the beamline design are carefully studied. The present calculations demonstrate that in the case of 0.937 nm-rad brilliance of undulator is increased by a factor of about 5. For bending magnet, flux is reduced almost 1 order of magnitude for hard x-ray regime. Because of smaller size of the source for undulator at the case of 0.937 nm-rad, we can achieve to a smaller spot size and higher resolution with easier focusing systems and usual kind of monochromator than the emittance of 3.278 nm-rad and for the bending magnet hard x-ray beamline, size of the mirrors reduced 30% in the 0.937 nm-rad emittance case, so its result is shorter mirror, low cost and perhaps more challengeable heat load.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO057

Export •

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

WEPRO058

Photoemission Electron Microscopy Branch of Spectromicroscopy Beamline of the Iranian Light Source Facility

undulator, photon, focusing, brilliance

2078

S. Amiri, H. Ghasem, A. Gholampour, H. Khosroabadi, J. Rahighi
ILSF, Tehran, Iran
H. Ghasem, M. Lamehi Rashti
IPM, Tehran, Iran

The Spectromicroscopy beamline is one of the day one beamlines of the Iranian Light Source Facility project in the field of soft x-ray spectroscopy. This beamline is designed to cover the 90-2500eV energy range with about 8000 resolving power, and the minimum spot size of about 10×4 micrometer 2 at sample position. Brilliance, flux and photon size and divergence in the whole range of energy has been calculated for a 4.3m linear undulator using SPECTRA code. This undulator has 10¹⁵ ph/s(0.1% B.W.) photon flux at 96 eV energy & 400 mA electron current. A circular pinhole with maximum diameter size of 2.52mm has been inserted in a distance of 10m from the source to pass 95% radiated. Primary layout of this branch includes a collimating mirror, a varied included-angle plane grating monochromator, and a KB bendable elliptical cylinder mirror. The ray tracing calculation by using computational software SHADOW has been done to determine and optimize of the important optical parameters. Three plane gratings with different uniform line density (700, 900, 1200 lines/mm) have been used to cover the whole energy range with the resolving power of 0.75-0.8×104 depending on the photon energy.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO058

Export •

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

WEPRO064

Recent Results of the HESR RF System

operation, cavity, impedance, accumulation

2094

R. Stassen, F.J. Etzkorn, R. Greven, T. Katayama, R. Maier, G. Schug, H. Stockhorst
FZJ, Jülich, Germany

The FAIR complex (Facility for Antiprotons and Ion Research) will be built in different stages. Due to the postponed RESR in the first stage, both RF-cavities of the HESR have to operate in different modes to achieve the required beam quantity and quality. The RF-system of the HESR will now consists of two identical cavities with a common low-level RF control (LLRF). Both cavities will be driven by low noise solid state amplifiers. Each cavity contains of one gap and two tanks operating in push-pull mode and each tank will house 6 ring cores wound of modern magnetic nano-alloy ribbon. Meanwhile all ring cores were delivered and first results at low power and at high power will be presented. The construction of the new air cooling concept is now in the final stage.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO064

Export •

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

WEPRO090

Status of KAERI 6 MeV 9.3 GHz X-Band Electron Linac for Cancer Treatment System

linac, cavity, gun, radiation

2168

B.N. Lee, B.C. Lee, S.H. Lee, S. Lee, H.D. Park, K.B. Song
KAERI, Dae-jeon, Republic of Korea
P. Buaphad, Y. Kim
ISU, Pocatello, Idaho, USA
S.S. Cha
UST, Daejeon City, Republic of Korea

Funding: This work was supported by a grant from the (NRF funded by the MSIFP, Korea (No.2013M2A2A4023350) and the Industrial Strategic technology development program, 10043897, funded By the MOTIE, Korea.
The X-band RF linear accelerators (LINAC’s) are popular for medical application due to its compactness. To increase the precision of treatment accuracy under circumstance in which the LINAC is mounted on an apparatus such as gantry frame or robot-arm; this is an advantage as the weight and size are more reduced. It is a 9.3 GHz magnetron with the most readily available RF generator in the X-band frequencies from 8 GHz to 12 GHz and the magnetron is mainly used for the source of the RF power in a compact LINAC. The average power of the magnetron at 9.3~GHz is generally a few MW and this amount could provide a sufficient radiation dose-rate for tumour therapy. KAERI has been developing a new compact 9.3 GHz X-band electron LINAC for a cancer treatment system. The maximum energy of the electron beam is 6 MeV and the average beam power at the tungsten target is about 1 kW. In this paper, we describe the status of development of the 6 MeV X-band LINAC at KAERI.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO090

Export •

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

WEPRO093

Possibility of Application of THz Wiggler in Low Energy FEL for Measurements of Electron Bunch Longitudinal Structure

wiggler, laser, radiation, undulator

2177

E. Syresin, S.A. Kostromin, R.S. Makarov, N.A. Morozov, D. Petrov
JINR, Dubna, Moscow Region, Russia
M. Krasilnikov
DESY Zeuthen, Zeuthen, Germany

Funding: The work is funded by HGDF-RFBR Grant HRJRG-400
The infrared undulator constructed at JINR and installed at FLASH in 2007 is used for longitudinal bunch shape measurements in the range of several tenths of μm. The presented below electromagnetic wiggler is applied for a narrow-band THz radiation for measurements of electron bunch longitudinal structure in FEL with electron energy of several tenths of MeV. This is a planar electromagnetic device with 6 regular periods, each of 30 cm long. The K parameter is varied in the range 0.5- 7.12 corresponding to a range B=0.025- 0.356 T of the peak field on axis. The wiggler is simulated for 19.8 MeV/c FEL. The bunch compression scheme allows the whole wavelength range to be covered by super-radiant emission with a sufficient form factor. The wavelength range corresponds to 126 μm - 5.3 mm for the electron beam momentum of 19.8 MeV/c. The 3D Opera simulations of THz wiggler will be discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO093

Export •

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

WEPRO096

X-ray Radiation Source for Low Dose Angiography based on Channeling Radiation

radiation, optics, photon, cavity

2186

S.M. Polozov, T.V. Bondarenko
MEPhI, Moscow, Russia

Angiography is one of the most reliable and contemporary procedure of the vascular system imaging. X-ray spectrums provided by all modern medical angiographs are too broad to acquire high contrast images and provide low radiation dose at the same time. The new method of narrow X-ray spectrum achieving is based on the idea of channelling radiation application. The X-ray filters used in this method allows eliminating the high energy part of the spectrum and providing dramatic dose reduction. The scheme of the facility including the X-ray filter is discussed. The results of the spectrum analysis for the channelling radiation source and typical angiography X-ray tube are discussed. Doses obtained by the water phantom and contrast of the iodine agent image are also provided for both cases.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO096

Export •

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

WEPRO097

The Base Parameters of the Compact 27 GHz Electron Linac for Medical Application

linac, simulation, injection, coupling

2189

S.M. Polozov, T.V. Bondarenko, Yu.D. Kliuchevskaia, V.I. Rashchikov
MEPhI, Moscow, Russia

A compact and light-weight electron linac is attractive for a number of medical applications including intra-operational and cyber-knife systems. The design of such an accelerator can nowadays be based on using of a powerful high-voltage high-frequency gyrotron which can provide now in pulsed regime a peak power up to 15 MW at the frequency about of 30 GHz. Taking into account this possibility, the paper presents the results of design and numerical simulations for the electron beam dynamics in a linac with the operating frequency of 27 GHz. Designed linac consists of two parts: gentle buncher and main accelerating section. The beam bunching is complicated at 1 cm wavelength because high energy about 2 MeV is necessary for beam injection into the main stage with v/c=1. Beam dynamics simulations are held using BEAMDULAC-BL code*. The electrodynamics of accelerating structure based on biperiodic structure is presented. The electron gun simulation is also discussed. The RF feeding is planned to be realized using a gyrotron to be designed in IAP RAS. The gyrotron is capable to produce 2 MW peak RF power in pulses with pulse duration 400 μs and repetition rate 10 Hz.
T.V. Bondarenko, E.S. Masunov, S.M. Polozov. BEAMDULAC-BL code for 3D simulation of electron beam dynamics taking into account beam loading and coulomb field. PAST, 2014 (in press).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO097

Export •

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

WEPRO098

Producing Two-photon Planar Sources at an Electron Accelerator

target, photon, radiation, simulation

2192

V.L. Uvarov, N.P. Dikiy, A.N. Dovbnya, Yu.V. Lyashko, Yu.V. Rogov, V.A. Shevchenko, A.Eh. Tenishev
NSC/KIPT, Kharkov, Ukraine

Gamma-sources with two-energy spectrum are used in industrial and medical diagnostics for quantitative introscopy (tomography). Commonly, such sources are obtained by a reactor technology (153Gd) or using an ultrastable X-ray tube with properly shaped spectrum of radiation. We suggested utilize the 179Ta isotope (Ex~ 55 keV, T1/2= 665 day) in combination with 57Co (Eγ=122 keV, T1/2=273 day). A soft technology for producing planar sealed 179Ta/57Co sources at an electron accelerator by X-ray irradiation of a target from natural tantalum and nickel was developed. The isotope yield and absorbed power of radiation in the target device vs electron beam energy were calculated using a modified transport code PENELOPE-2008. The results of experiment conducted to determine the yields of the target isotopes and by-products are in good agreement with the simulation data.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO098

Export •

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

WEPRO103

Femtosecond Time-resolved Transmission Electron Microscopy using an RF Gun

gun, laser, emittance, cathode

2205

J. Yang, M. Gohdo, K. Kan, T. Kondoh, K. Tanimura, Y. Yoshida
ISIR, Osaka, Japan
J. Urakawa
KEK, Ibaraki, Japan

The first prototype of RF gun based relativistic-energy electron microscopy has been constructed at Osaka University to study ultrafast structural dynamic processes in matter. The RF gun driven by a femtosecond laser has generated a 100-fs-pulse MeV electron beam with emittance of 0.1 mm-mrad and energy spread of 10^-4. Both the electron diffraction and image measurements have been succeeded in the prototype using the femtosecond electron beam. In the diffraction measurement, an excellent quality of diffraction pattern was acquired with electron number of 10⁶. The single-shot measurement is available in the prototype. In the image measurement, the TEM image was acquired with a total electron number of 10⁸. The magnification was 3,000 times. In the next step, we will reduce further the emittance to increase the beam brightness on the sample, and then improve the spatial resolution to <10 nm.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO103

Export •

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

WEPRO107

Positron Annihilation Spectroscopy at the LEPTA Facility

positron, background, vacuum, scattering

2215

P. Horodek
JINR/DLNP, Dubna, Moscow region, Russia
A.G. Kobets, I.N. Meshkov, O. Orlov, A.A. Sidorin
JINR, Dubna, Moscow Region, Russia

Since 2009 year the LEPTA facility at Joint Institute for Nuclear Research in Dubna is operated with positron beam. Today it is developed into two directions. The first one is getting orthopositronium flux in flight. Slow positrons from 22Na source are accumulated in Surko trap and then are injected into the ring where they should overlap with electrons from the single-pass electron beam. In this way the flux of orthopositronium atoms will appear and will be observed in the process of registration of gamma quanta from annihilation process. The second group of works focuses on using the positron injector for Positron Annihilation Spectroscopy (PAS) applications. This method is dedicated to detection of structural defects as vacancies in the solid body lattice. The latest progress of this technique is strictly connected with measurements of PAS characteristics using positron beams. The progress in the LEPTA development, the first results obtained in the PAS, idea and actual state of works concerning the construction of the pulsed positron beam will be presented. The creation of pulsed positron beams is the modern tendency in the PAS domain.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO107

Export •

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

WEPRO108

Electron Diffraction on VELA at Daresbury

gun, laser, experiment, space-charge

2218

M. Surman
STFC/DL/SRD, Warrington, Cheshire, United Kingdom
P. Aden, R.J. Cash, D.M.P. Holland, M.D. Roper
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
W.A. Bryan
Swansea University, Swansea, Wales
J.A. Clarke, J.W. McKenzie
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
P.D. Lane, D.A. Wann
University of York, York, United Kingdom
J.G. Underwood
UCL, London, United Kingdom

Accelerator based Ultrafast Electron Diffraction (UED) is a technique for static and dynamic structural studies in material and biological sciences. The recently commissioned VELA accelerator at the Daresbury Laboratory provides multi-MeV beams for science and industry and will provide a test bed for the UK electron diffraction community. We present the design of the diffractometer currently being installed on VELA which will allow capture of a single shot diffraction pattern with a 1 pC electron bunch and outline future options.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO108

Export •

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

WEPRO113

Status of the Radiation Source ELBE Upgrade

laser, operation, radiation, klystron

2233

P. Michel, T.E. Cowan, U. Lehnert, U. Schramm
HZDR, Dresden, Germany

ELBE is based on a 40 MeV superconducting Electron Linac able to operate in CW mode and provides manifold secondary user beams. The suite of secondary beams include: two free electron lasers operating in the IR/THz regime; a fast neutron beam; a Bremsstrahlung gamma-ray beam; a low-energy positron beam; and patented single-electron test beams. The primary electron beam is also used for radiobiology research, or in interaction with ultra-intense PW-class lasers. Through 2014 ELBE will be upgraded to a Centre for High Power Radiation Sources. The ELBE beam current was increased to 1.6 mA by using novel solid state RF amplifiers. The concept also contains additional broad and narrow band coherent THz sources and the development of a 500 TW TiSa Laser and even a 1.5 PW diode pumped laser system. Laser plasma electron acceleration and proton acceleration experiments for medical applications are planned. Additionally, coupled electron laser beam experiments like Thomson scattering or injection of ELBE electron into the laser plasma will be done.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO113

Export •

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

WEPRO114

SALOME: An Accelerator for the Practical Course in Accelerator Physics

cathode, quadrupole, experiment, emittance

2235

V. Miltchev, D. Riebesehl, J. Roßbach, M. Trunk
Uni HH, Hamburg, Germany
O. Stein
CERN, Geneva, Switzerland

SALOME (Simple Accelerator for Learning Optics and the Manipulation of Electrons) is a short low energy linear electron accelerator built by the University of Hamburg. The goal of this project is to give the students the possibility to obtain hands-on experience with the basics of accelerator physics. In this contribution the layout of the device will be presented. The most important components of the accelerator will be discussed and an overview of the planned demonstration experiments will be given.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO114

Export •

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

WEPRO115

The Star Project

laser, photon, linac, scattering

2238

A. Bacci, D.T. Palmer, L. Serafini, V. Torri
Istituto Nazionale di Fisica Nucleare, Milano, Italy
R.G. Agostino, G. Borgese, M. Ghedini, F. Martire, C. Pace
UNICAL, Arcavacata di Rende, Italy
D. Alesini, M.P. Anania, M. Bellaveglia, F.G. Bisesto, G. Di Pirro, A. Esposito, M. Ferrario, A. Gallo, G. Gatti, A. Ghigo, B. Spataro, C. Vaccarezza, F. Villa
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
G. D'Auria, A. Fabris, M. Marazzi
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
T. Levato
Czech Republic Academy of Sciences, Institute of Physics, Prague, Czech Republic
V. Petrillo
Universita' degli Studi di Milano, Milano, Italy
E. Puppin
Politecnico/Milano, Milano, Italy
P. Tomassini
Università degli Studi di Milano, Milano, Italy

We present on overview of the STAR project (Southern european Thomson source for Applied Research), in progress at the Univ. of Calabria (Italy) aimed at the construction of an advanced Thomson source of monochromatic tunable, ps-long, polarized X-ray beams, ranging from 20 to 140 keV. The project is pursued in collaboration among: Univ. della Calabria, CNISM, INFN and Sincrotrone Trieste. The X-rays will be devoted to experiments of matter science, cultural heritage, advanced radiological imaging with micro-tomography capabilities. One S-band RF Gun at 100 Hz will produce electron bunches boosted up to 60 MeV by a 3m long S-band TW cavity. A dogleg will bring the beam on a parallel line, shielding the X-ray line from the background radiation due to Linac dark current. The peculiarity of the machine is the ability to produce high quality electron beams, with low emittance and high stability, allowing to reach spot sizes around 15-20 microns, with a pointing jitter of the order of a few microns. The collision laser will be based on a Yb:Yag 100 Hz J-class high quality laser system, synchronized to an external photo-cathode laser and to the RF system to better than 1 ps time jitter.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO115

Export •

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

WEPRO116

Direct High Power Laser Diagnostic Technique Based on Focused Electron Bunch

laser, solenoid, scattering, experiment

2242

R. Sato, A. Endo, K. Nonomura, K. Sakaue, M. Washio, Y. Yoshida
Waseda University, 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 desire to measure laser profile in collision point. However, focused laser profile has not been observed directory by existing techniques. We have been developing laser profiler based on laser Compton scattering. Laser profile can be measured by scanning focused electron beam while measuring Compton scattering signal. This method is suitable for a high intensity laser, but very small spot size of electron beam is required. To achieve small spot size, we use S-band photocathode rf gun and special design solenoid lens. The beam size was simulated by General particle tracer (GPT) and directory measured by Gafchromic film HD-810. We have succeeded in observing minimum beam size of about 20 μm rms. We are preparing beam scanning system, pulse CO2 laser and a detector for Compton signal. In this conference, we will report the results of focused electron beam measurement and future prospective.
Work supported by NEDO(New Energy and Industrial Technology Development Organization).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO116

Export •

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

WEPRO118

THz Radiation Generation in Multimode Wakefield Structures

radiation, wakefield, experiment, linac

2248

S.P. Antipov, S.V. Baryshev, C.-J. Jing, A. Kanareykin, P. Schoessow
Euclid TechLabs, LLC, Solon, Ohio, USA
M.G. Fedurin
BNL, Upton, Long Island, New York, USA
W. Gai, A. Zholents
ANL, Argonne, Illinois, USA
D. Wang
TUB, Beijing, People's Republic of China

Funding: DOE SBIR
A number of methods for producing sub-picosecond electron bunches have been demonstrated in recent years. A train of these bunches is capable of generating THz radiation via multiple mechanisms like transition, Cherenkov and undulator radiation. We propose to use a bunch train like this to selectively excite a high order mode in a dielectric wakefield structure. This allows us to use wakefield structures that are geometrically larger and easier to fabricate for beam-based THz generation. In this paper we present a THz source design based on this concept and experimental progress to date.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO118

Export •

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

WEPME001

Virtual Cathode Drive Laser Diagnostics with a Large Dynamic Range for a Continuous Wave SRF Photoinjector

laser, cathode, diagnostics, operation

2251

E. Panofski, A. Jankowiak, T. Kamps, G. Klemz
HZB, Berlin, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association
In a SRF photoinjector the close relationship between the laser pulse and the generated electron bunch parameters requires continuous monitoring of some of the laser pulse parameters. A laser diagnostic system, called virtual cathode, is a key part of a system that controls the stability of the laser. One of the main challenges for the virtual cathode is to cover the large dynamic range of the photocathode laser between commissioning at 120 Hz and operation at 1.3 GHz repetition rate with constant laser pulse parameters. The design of the virtual cathode as well as first measurements with a photocathode drive laser for the SRF injector test facility GunLab of BERLinPro will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME001

Export •

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

WEPME004

Prediction of Severe Electron Loading of High-gradient Accelerating Structures based on Field Emission Measurements of Nb and Cu Samples

cavity, vacuum, high-voltage, factory

2258

S. Lagotzky, G. Müller
Bergische Universität Wuppertal, Wuppertal, Germany

Funding: The work is funded by BMBF project 05H12PX6.
Enhanced field emission (EFE) limits the performance of both superconducting and normal conducting high-gradient accelerating structures. Systematic field emission scanning microscopy and correlated SEM/EDX measurements of relevant Nb and Cu samples have revealed particulates and surface irregularities with field enhancement factors b = 10 - 90 as origin of EFE. Based on sufficient emitter statistics, an exponential increase of the emitter number density N with increasing surface field (E) was found. This allows a prediction of the EFE loading of future ILC and CLIC accelerating structures by scaling of N to relevant E and using a weighted integration over the high-field cavity surface. Accordingly, an electropolished (Ra < 300 nm) and dry-ice cleaned (DIC) TESLA-shape 9-cell 1.3 GHz Nb cavity * will still suffer from EFE at Eacc = 35 MV/m (N = 0.3 /cm² at Epeak = 70 MV/m). Moreover, a diamond-turned, chemically etched and DIC 11.2 GHz Cu structure ** will breakdown at Eacc = 100 MV/m (N = 20 /cm² at Epeak = 243 MV/m). Possible improvements, i.e. by emitter processing will be discussed.
* ILC Technical Design Report (2013)
** A. Grudiev and W. Wuensch, Proceedings of LINAC2010, Tsukuba, Japan, pp. 211 - 213

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME004

Export •

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

WEPME005

Enhanced Field Emission and Emitter Activation on Flat Dry-ice Cleaned Cu Samples

site, vacuum, factory, gun

2261

S. Lagotzky, G. Müller, P. Serbun
Bergische Universität Wuppertal, Wuppertal, Germany
S. Calatroni, T. Muranaka
CERN, Geneva, Switzerland

Enhanced field emission (EFE), resulting in dark currents and electric breakdowns, is one of the main gradient limitations for the CLIC accelerating structures (actual design Eacc = 100 MV/m, Epeak = 240 MV/m *). Measurements on diamond-turned, flat (Ra = 158 nm) Cu samples showed first EFE at surface fields Es = 130 MV/m. In order to reduce EFE, we have installed a commercial dry ice cleaning (DIC) system in a clean room environment (class iso 5). Accordingly, the number density of emitters (N) was significantly decreased by DIC from N = 52 /cm² to N = 12 /cm² at Es = 190 MV/m. Furthermore we have tested two diamond-turned and chemically etched (SLAC treatment, Ra = 150 nm) Cu samples after DIC resulting in EFE onset at 230 MV/m. Locally measured I(V) curves of the strongest emitters yielded field enhancement factors b = 10 – 90 (10 – 85) on the diamond-turned (chemically etched), respectively. SEM and EDX investigations of the located emission sites revealed surface defects and few particulates (Al, Ca, Si) as origin of the EFE. Moreover, strong emitter activation effects were observed. A possible breakdown mechanism based on this EFE activation will be discussed.
* A. Grudiev and W. Wuensch, Proceedings of LINAC2010, Tsukuba, Japan, pp. 211 - 213

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME005

Export •

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

WEPME007

Multi-Bunch Generator Cavity

cavity, impedance, cathode, coupling

2267

E.A. Savin, S.V. Matsievskiy, Ya.V. Shashkov, N.P. Sobenin
MEPhI, Moscow, Russia
A.A. Zavadtsev
Nano, Moscow, Russia

The concept of the six bunch generator cell for the washers and diaphragm loaded structure (Moscow Meson Factory) power supply is proposed. The required power is 0.8 MW on the 991 MHz frequency. The high-voltage electron gun produces electron bunches and puts them into the cylindrical resonator tuned to TE02 mode and operating frequency. Bunches produces RF field that takes energy from the following bunches and then energy transfer to the accelerating structure throw the tuned coupling system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME007

Export •

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

WEPME009

Principles for Design of High Power Pulsed Microwave Devices and Devices with Low Operating Voltage for Accelerators

klystron, gun, controls, solenoid

2273

K.G. Simonov, A.A. Borisov, I.I. Golenitskiy, A.V. Mamontov, A.N. Yunakov
ISTOK, Moscow Region, Russia
O.A. Morozov
Research and Production Co. "MAGRATEP", Fryazino, Russia

The principle of obtaining the extra-high pulsed power at significantly lower operating voltages by creating klystrons with magnetron gun; location of several such klystrons in a single solenoid with a homogeneous magnetic field and summing their output capacities is proposed. The principle of designing of high-power klystron with multi-beam magnetron gun with anode modulation and several energy outputs is proposed. The principle of designing of high-power klystron magnetron gun with multi-beam magnetron gun with control electrode modulation and several energy outputs is proposed. Are given the results of theoretical studies demonstrating the feasibility of such devices and high-power microwave systems based on them. During development of principles of obtaining an extra-high power were used the design of single-beam klystron with magnetron gun with control electrode modulation created at RPC "Istok".

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME009

Export •

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

WEPME025

Design and Performance of Ultimate Vacuum System for the AREAL Test Facility

vacuum, gun, cathode, dipole

2311

A.A. Gevorgyan, V.S. Avagyan, B. Grigoryan, T.H. Mkrtchyan, A.S. Simonyan, V. V. Vardanyan
CANDLE SRI, Yerevan, Armenia

The design specification of the AREAL test facility require the residual pressure at the level of 1nTorr with beam through entire vacuum chamber. We present the main features of the vacuum system, including the design and fabrication peculiarities of the dedicated components like dipole magnet stainless steel vacuum chamber and the cubes for beam diagnostic stations. The philosophy and instrumentation of the vacuum system are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME025

Export •

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

WEPME030

Design and Construction of a Prototype Sputter ion Pump in ILSF

ion, vacuum, cathode, operation

2323

O. Seify, H. Ghasem, S. Kashani, J. Rahighi
ILSF, Tehran, Iran
H. Ghasem
IPM, Tehran, Iran

Design and construction process of special kind of sputter ion pump is described briefly in this paper. In order to investigate the optimization of effective parameters in choosing and designing ILSF ion pumps, this pump has been designed and manufactured. By optimizing some parameters such as dimension and shape of penning cells, anode voltage, magnetic field and internal structure of pump, it is possible to significantly decrease the cost of construction and operation of synchrotron vacuum system. One of the most important advantages of this design, is that the initial parameters and finally internal structure of the prototype pump are changeable easily. The effect of parameters like anode voltage, magnetic field etc. on pumping speed and final pressure are described. With the existing optimization it is expected that an ultimate pressure of 1x10^-11 Torr could be achieved.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME030

Export •

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

WEPME031

Magnetic Design of the First Prototype Pure Permanent Magnet Undulator for the ILSF

undulator, brilliance, radiation, permanent-magnet

2326

A. Ramezani Moghaddam, J. Rahighi
ILSF, Tehran, Iran
H. Ghasem
IPM, Tehran, Iran
M. Lamehi Rashti
Nuclear Science & Technology Research Institute, Tehran, Iran
A. Ramezani Moghaddam
NSTRI, Tehran, Iran

Iranian light source facility (ILSF) is a 3GeV, 400 mA, 3rd generation light source under design and construction. This paper describes the details of the preliminary magnetic design of the first prototype PPM undulator for the ILSF. In the preliminary design, the undulator period and some other parameters have been determined to reach desired x-ray spectrum to be used for soft x-ray application. A PPM layout and a model undulator with 16 poles is used to calculate the properties of the designs.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME031

Export •

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

WEPME032

Detailed Investigation of the Low Energy Secondary Electron Yield of Technical Cu and its Relevance for LHC

gun, simulation, dipole, operation

2329

R. Cimino, L.A. Gonzalez, A.L. Romano
INFN/LNF, Frascati (Roma), Italy
R. Cimino, G. Iadarola, G. Rumolo
CERN, Geneva, Switzerland
R. Larciprete
ISM-CNR, Rome, Italy

The detailed study of the Secondary Electron Yield (SEY) of technical Cu for very low electron landing energies (from 0 to 30 eV) is very important for electron cloud build up in high intensity accelerators and in many other fields of research. However, this question has been rarely addressed due to the intrinsic experimental complexity to control very low energy electrons. Furthermore, several results published in the past have been recently questioned for allegedly suffering from experimental systematics. In this paper, we critically review the experimental method used to study low energy SEY and define more precise energy regions, in which the experimental data can be considered valid. The new SEY curves are then fed into e-cloud simulation codes to address their impact for electron cloud predictions in the LHC.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME032

Export •

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

WEPME033

Search for New e-cloud Mitigator Materials for High Intensity Particle Accelerators

experiment, vacuum, embedded, impedance

2332

R. Cimino, S.T. O'connor, A.L. Romano
INFN/LNF, Frascati (Roma), Italy
V. Baglin, G. Bregliozzi, R. Cimino
CERN, Geneva, Switzerland
M.R. Masullo
INFN-Napoli, Napoli, Italy
S. Petracca, A. Stabile
INFN-Salerno, Baronissi, Salerno, Italy

Electron cloud is an ubiquitous effect in positively charged particle accelerators and has been observed to induce unwanted detrimental impacts on beam quality, stability, vacuum etc. A great effort has been recently devoted to the search of new material morphology and/or coatings which can intrinsically mitigate beam instabilities deriving from electron cloud effects. In this context, we present some characterization of Cu foams, available from the market, and their qualification in terms of their vacuum behavior, impedance, secondary electron yield, gas desorption etc. More experimental effort is required to finally qualify foams as a mature technology to be integrated in accelerator environments. But, our preliminary results suggests that, when compatible with geometrical constrains, Cu foams can be utilized when low desorption yields are required and as e-cloud moderator in future particles accelerators.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME033

Export •

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

WEPME034

Soft X-ray Reflectivity and Photoelectron Yield of Technical Materials: Experimental Input for Instability Simulations in High Intensity Accelerators

photon, optics, radiation, synchrotron

2335

R. Cimino
INFN/LNF, Frascati (Roma), Italy
R. Cimino
CERN, Geneva, Switzerland
F. Schäfers
HZB, Berlin, Germany

High luminosity particle accelerators can suffer from serious performance drop or limitations due to interaction of the synchrotron radiation produced by the accelerator itself with the accelerator walls. Such interaction may produce a number of photoelectrons, that can either seed electron cloud related instabilities and/or interact anyway with the beam itself, potentially causing its deterioration. To correctly take these effects into account simulation codes depends on the realistic knowledge of Reflectivity and Photoelectron Yield of technical material. In this work we present relevant experimental data for some of the mostly used technical surfaces in accelerators.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME034

Export •

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

WEPME036

Simulation of the Trajectory of Electrons in a Magnetron Sputtering System of TiN with CST Particle Studio

vacuum, cathode, simulation, experiment

2341

J. Wang, L. Fan, Y.Z. Hong, W.L. Liu, X.T. Pei, K. Tang, Y. Wang, W. Wei, Y.H. Xu, B. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: National Nature Science Foundation of China under Grant Nos.11075157.
In the process of magnetron sputtering deposition, electromagnetic fields have an important influence on the trajectory of particle movement and the properties of the TiN thin film in many cases. Even for simple geometries, the analytical prediction for charged particles trajectories is extremely cumbersome, so numerical simulations are essential to obtain a better understanding of the possible effects and helpful to optimize the design of experimental facility and experimental process. A software of CST PARTICLE STUDIOTM has been used to simulate the effect of magnetic and electric fields on electrons trajectories in the process of film coating. According to the simulation results, the improvement measures of the system design and experimental process have been achieved. The author put forward the improvement measures on film coating process according to the simulation results. The result shows that it is feasible and convenient to use three dimensional tool in the simulation of trajectory of electrons in a magnetron sputtering system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME036

Export •

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

WEPME040

Development of Aluminium Vacuum Chambers for the LHC Experiments at CERN

vacuum, experiment, beam-losses, factory

2354

M.A. Gallilee, P. Chiggiato, P. Costa Pinto, L.M.A. Ferreira, P. Lepeule, J. Perez Espinos, L. Prever-Loiri, A. Sapountzis
CERN, Geneva, Switzerland

Beam losses may cause activation of vacuum chamber walls, in particular those of the Large Hadron Collider (LHC) experiments. For the High Luminosity LHC, the activation of such vacuum chambers will increase. It is therefore necessary to use a vacuum chamber material which interacts less with the circulating beam. While beryllium is reserved for the collision point, a good compromise between cost, availability and transparency is obtained with aluminium alloys; such materials are a preferred choice with respect to austenitic stainless steel. Manufacturing a thin-wall aluminium vacuum chamber presents several challenges as the material grade needs to be machinable, weldable, leak-tight for small thicknesses, and able to withstand heating to 250°C for extended periods of time. This paper presents some of the technical challenges during the manufacture of these vacuum chambers and the methods for overcoming production difficulties, including surface treatments and NEG thin-film coating.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME040

Export •

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

WEPME042

The LHC Vacuum Pilot Sectors Project

vacuum, controls, radiation, detector

2360

B. Henrist, V. Baglin, G. Bregliozzi, P. Chiggiato
CERN, Geneva, Switzerland

The operation of the CERN Large Hadron Collider (LHC) at nominal beam parameters is expected for the next years (2015). Increased synchrotron-radiation stimulated-desorption and electron-cloud build-up are expected. A deep understanding of the interactions between the proton beams and the beampipe wall is mandatory to control the anticipated beam-induced pressure rise. A Vacuum Pilot Sector (VPS) has been designed to monitor the performance of the vacuum system with time. The VPS is installed along a double LHC room temperature vacuum sector (18 m long, 80 mm inner diameter beam pipes) and includes 8 standard modules, 1.4 m long each. Such modules are equipped with residual gas analysers, Bayard-Alpert gauges, photon and electron flux monitors, etc. The chosen modular approach opens the possibility of studying different configurations and implementing future modifications. This contribution will describe the apparatus, the control system designed to drive measurements and possible applications during the next LHC operational phase.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME042

Export •

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

WEPME047

CERN Vacuum System Activities during the Long Shutdown 1: the LHC Beam Vacuum

vacuum, experiment, cryogenics, collimation

2375

V. Baglin, G. Bregliozzi, P. Chiggiato, J.M. Jimenez, G. Lanza
CERN, Geneva, Switzerland

After the Long Shutdown 1 (LS1) and the consolidation of the magnet bus bars, the CERN Large Hadron Collider (LHC) will operate with nominal beam parameters. Larger beam energy, beam intensities and luminosity are expected. Despite the very good performance of the beam vacuum system during the 2010-12 physics run (Run 1), some particular areas require attention for repair, consolidation and upgrade. Among the main activities, a large campaign aiming at the repair of the RF bridges of some vacuum modules is conducted. Moreover, consolidation of the cryogenic beam vacuum systems with burst disk for safety reasons is implemented. In addition, NEG cartridges, NEG coated inserts and new instruments for the vacuum system upgrade are installed. Besides these activities, repair, consolidation and upgrades of other beam equipment such as collimators, kickers and beam instrumentations are carried out. In this paper, the motivation and the description for such activities, together with the expected beam vacuum performance after LS1, are described in detail.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME047

Export •

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

WEPME049

Coupled Simulations of the Synchrotron Radiation and Induced Desorption Pressure Profiles for the HiLumi-LHC Triplet Area and Interaction Points

vacuum, simulation, photon, detector

2381

R. Kersevan, V. Baglin, G. Bregliozzi
CERN, Geneva, Switzerland

The HiLumi-LHC machine upgrade has officially started as an approved LHC project (see dedicated presentations at this conference on the subject). One important feature of the upgrade is the installation of very high-gradient triplet magnets for focusing the beams at the collision points of the two high-luminosity detectors ATLAS and CMS. Other important topics are new superconducting D1 magnets, installation of crab cavities, and re-shuffling of the dispersion suppression area. Based on the current magnetic lattice set-up and beam orbits, a detailed study of the emission of synchrotron radiation (SR) and related photon-induced desorption (PID) has been carried out. A significant amount of SR photons are generated by the two off-axis beams in the common vacuum chamber of the triplet area, about 57 m in length. Ray-tracing Montecarlo codes SYNRAD⁺ and Molflow+ have been employed in this study. The related PID pressure profiles will be shown, together with simulations using the code VASCO for the analysis of beam losses and background in the detectors, including electron cloud effects.
(*) The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME049

Export •

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

WEPME054

Design and Fabrication of the Novel-type Ceramic Chamber

vacuum, site, HOM, detector

2393

L.H. Wu, C.K. Chan, J.-R. Chen, G.-Y. Hsiung, S-N. Hsu, T.Y. Lee
NSRRC, Hsinchu, Taiwan
J.-R. Chen
National Tsing Hua University, Hsinchu, Taiwan

A ceramic chamber of novel type has been designed and fabricated. The uniformity of its inner thin film of deposited metal is improved to have a thickness error about 1 %. The average straightness error of the chamber (length 550 mm) is developed to be less than 55 μm. To fabricate the ceramic chamber of novel type, we first cleaned and joined the two halves; the metal films were deposited by sputtering. These two halves were next sealed with a glass powder colloid to become a ceramic tube. The rate of outgassing of this colloid is 3.57×10^-12 Torr L s⁻¹ cm^-2 after baking. The ceramic tube was connected to a stainless-steel flange with the aid of a glass powder colloid and TIG welding. This ceramic test chamber will be installed in the experimental system to analyze the residual gas.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME054

Export •

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

WEPME056

Further Optimisation of NEG Coatings for Accelerator Beam Chamber

vacuum, injection, experiment, photon

2399

O.B. Malyshev, R. Valizadeh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The non-evaporable getter (NEG) coating, invented at CERN in 90s, is used nowadays in many accelerators around the world. The main advantages of using NEG coatings are evenly distributed pumping speed, low thermal outgassing rates and low photon and electron stimulated gas desorption. The only downside of the NEG is its selective pumping: it pumps H2, CO, CO2 and some other gas species, but does not pump noble gases and hydrocarbons. However, in the accelerators where NEG coating could be beneficial, there is synchrotron radiation and photoelectrons that bombard vacuum chamber walls, it was found in our study that hydrocarbons can be pumped by NEG coating under electron and, most likely, photon bombardment. The detail and the results of this study are reported in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME056

Export •

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

WEPME057

The Secondary Electron Yield from Transition Metals

vacuum, gun, collider, hadron

2403

S. Wang, M.D. Cropper
Loughborough University, Loughborough, Leicestershire, United Kingdom
O.B. Malyshev, E.A. Seddon, R. Valizadeh, S. Wang
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Non-evaporable getter thin films, which are currently being used in the ultra-high vacuum system of the Large Hadron Collider, normally consist of Ti, Zr and V, deposited by physical vapour deposition. In this study, the secondary electron yield (SEY) of bulk Ti, Zr, V and Hf have been investigated as a function of electron conditioning. The maximum SEYs of as-received Ti, Zr, V and Hf, are respectively 1.96, 2.34, 1.72 and 2.32, these reduce to 1.14, 1.13, 1.44 and 1.18 after electron conditioning. Surface chemical composition was studied by X-ray photoelectron spectroscopy which revealed that surface conditioning by electron bombardment promotes the growth of a thin carbon layer on the surface and consequently reduces the SEY of the surface as a function of electron dose. Heating a vanadium sample to 250°C resulted in diffusion of oxygen into the bulk and induced formation of metal carbide at the surface. However, the SEY stays the same even after heat-induced surface chemistry modification. Prolonged electron conditioning increases the surface oxygen but the surface is still predominantly covered with a thin graphitic layer and hence the SEY stays approximately constant.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME057

Export •

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

WEPME060

Yb DOPED HIGH-ENERGY UV ULTRAFAST LASER FOR AREAL FACILITY

laser, gun, alignment, emittance

2412

A. Lorsabyan, A.A. Gevorgyan, B. Grigoryan, A.S. Simonyan
CANDLE SRI, Yerevan, Armenia
V. Clet, A. Courjaud
Amplitude Systemes, Pessac, France
T.K. Sargsyan
LT-PYRKAL cjsc, Yerevan, Armenia

For electron generation from photocathode the new laser system was developed for the AREAL linear accelerator laboratory. Besides generating electrons using the laser, we plan to provide a laser beam for other experimental stations running in parallel. The performance and capabilities of the laser system including operating frequency, electron generation in multi-bunch regime and other advantages are presented. The outlooks and steps for further upgrade are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME060

Export •

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

WEPME067

Performance of the MTCA.4 Based LLRF System at FLASH

LLRF, operation, laser, free-electron-laser

2433

Ch. Schmidt, V. Ayvazyan, J. Branlard, L. Butkowski, M.K. Grecki, M. Hoffmann, F. Ludwig, U. Mavrič, K.P. Przygoda, H. Schlarb, H.C. Weddig, B.Y. Yang
DESY, Hamburg, Germany
W. Cichalewski, D.R. Makowski, A. Piotrowski
TUL-DMCS, Łódź, Poland
K. Czuba, I. Rutkowski, D. Sikora, M. Żukociński
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
I.M. Kudla
NCBJ, Świerk/Otwock, Poland
K. Oliwa, W. Wierba
IFJ-PAN, Kraków, Poland

The Free Electron Laser in Hamburg (FLASH) is the first linac which is equipped with a MTCA.4 based low level RF control system. Precise regulation of RF fields is essential for stable and and reproducible photon generation. Flash benefits from the performance increase using the new developments like, accurate and precise field detection devices. Further enourmous increase of processing capabilities allow for more sophisticated controller applications which better the overall performance of the regulation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME067

Export •

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

WEPME077

Advanced Automatic Frequency Control System for a Dual Energy S-band RF Electron Linear Accelerator

cavity, resonance, controls, simulation

2459

S.S. Cha
UST, Daejeon City, Republic of Korea
Y. Kim
ISU, Pocatello, Idaho, USA
B.C. Lee, B.N. Lee, H.D. Park, K.B. Song
KAERI, Daejon, Republic of Korea

Funding: This work was supported by a National Research Foundation of Korea (NRF) grant funded by the ministry of science ICT & future Planning (No. 2010-0026088), and MOTIE Korea (13-DU-EE-12).
The Radiation Instrumentation Research Division of Korea Atomic Energy Research Institute is developing a 2856 MHz dual energy [9, 6 MeV] s-band RF electron linear accelerator for security inspection. The s-band dual energy electron accelerator generates dual x-ray energy by irradiating a bunched electron beam from the cavity to a tungsten target. By detecting an x-ray, the cargo security inspection system can distinguish between organic and inorganic materials. Synchronization of the resonant frequency between the cavity and RF driver is an important factor for the stable operation of an accelerator. With a low RF driver power using the AFC, stable accelerator operations and a uniform output beam power can be obtained. This indicates that an accurate cargo inspection is possible. We used phase a frequency detector that can detect a wide frequency band and synchronize the resonance frequency between the RF driver and cavity. In this paper, we introduce a more advanced AFC system than a conventional AFC system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME077

Export •

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

WEPME083

VELA: A New Accelerator Technology Development Platform for Industry

FEL, cavity, target, experiment

2471

P.A. McIntosh, D. Angal-Kalinin, R.K. Buckley, S.R. Buckley, J.A. Clarke, P.A. Corlett, B.D. Fell, A.R. Goulden, C. Hill, F. Jackson, S.P. Jamison, J.K. Jones, L.B. Jones, A. Kalinin, L. Ma, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, A.J. Moss, T.C.Q. Noakes, Y.M. Saveliev, D.J. Scott, B.J.A. Shepherd, R.J. Smith, S.L. Smith, T.T. Thakker, A.E. Wheelhouse, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
N. Bliss, G. Cox, G.P. Diakun, A. Gleeson, T.J. Jones, K. Robertson, M.D. Roper, E. Snedden
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
S.T. Boogert
Royal Holloway, University of London, Surrey, United Kingdom
N.J. Boulding
FMB Oxford, Oxford, United Kingdom
A. Lyapin
JAI, Egham, Surrey, United Kingdom
E.J. Morton
CXR Ltd, Guildford, United Kingdom

The Versatile Electron Linear Accelerator (VELA) facility will provide enabling infrastructures targeted at the development and testing of novel and compact accelerator technologies, specifically through partnership with industry and aimed at addressing applications in medicine, health, security, energy and industrial processing. The facility has now been commissioned at Daresbury Laboratory and the facility is now being actively utilised by industrial groups who are able to take advantage of the variable electron beam parameters available on VELA to either demonstrate new techniques and/or processes or otherwise develop new technologies for future commercial realisation. Examples of which to be presented include; demonstration of a new cargo scanning process, characterisation of novel, high performance beam position monitors, as well as other technology development applications.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME083

Export •

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

WEPRI005

Processing and Testing of the SRF Photoinjector Cavity for BERLinPro

cavity, SRF, operation, niobium

2484

A. Burrill, W. Anders, A. Frahm, J. Knobloch, A. Neumann
HZB, Berlin, Germany
G. Ciovati, W.A. Clemens, P. Kneisel, L. Turlington
JLab, Newport News, Virginia, USA
E.N. Zaplatin
FZJ, Jülich, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association
The BERLinPro project is a compact, c.w. SRF energy recovery linac (ERL) that is being built to develop the accelerator physics and technology required to operate the next generation of high current ERLs. The machine is designed to produce a 50 MeV 100 mA beam, with better than 1 mm-mrad emittance. The electron source for the ERL will be a SRF photoinjector equipped with a multi-alkali photocathode. In order to produce a SRF photoinjector to operate reliably at this beam current HZB has undertaken a 3 stage photoinjector development program to study the operation of SRF photoinjectors in detail. The 1.4 cell cavity being reported on here is the second stage of this development, and represents the first cavity designed by HZB for use with a high quantum efficiency multi-alkali photocathode. This paper will describe the work done to prepare the cavity for RF testing in the vertical testing dewar at Jefferson Laboratory as well as the results of these RF tests.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI005

Export •

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

WEPRI011

Progress of R&D on SRF Cavities at DESY towards the ILC Performance Goal

cavity, SRF, factory, accelerating-gradient

2499

A. Navitski
DESY, Hamburg, Germany
A. Prudnikava, Y. Tamashevich
Uni HH, Hamburg, Germany

Funding: BMBF project 05H12GU9, Alexander von Humboldt Foundation, CRISP (No. 283745) and ”Construction of New Infrastructures-Preparatory Phase” ILC-HiGrade (No. 206711) of the EU 7th FP7/2007-2013 Programme.
The R&D program of the ILC-HiGrade group at DESY aims at a solid understanding and control of the industrial mass-production process of the superconducting radio-frequency accelerating cavities that are being manufactured for the European X-ray Free Electron Laser (EXFEL). This accelerator is currently under construction at DESY. As well as the main production cavities for XFEL, 24 additional cavities are being constructed as part of the ILC-HiGrade program. The goal is to identify the gradient-limiting factors and further refine the cavity-treatment technique to understand how to achieve gradients above 35 MV/m at >90% production yield in an industrial context. Techniques such as 2nd sound and temperature mapping for the quench detection, OBACHT optical inspections, as well as Centrifugal Barrel Polishing (CBP) and Local Grinding repair are foreseen as tools. Actual status, details, and achievements will be reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI011

Export •

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

WEPRI025

Studies of Fabrication Procedure of 9-cell SRF Cavity for ILC Mass-production at KEK.

cavity, HOM, gun, linear-collider

2528

T. Saeki, Y. Ajima, K. Enami, H. Hayano, H. Inoue, E. Kako, S. Kato, S. Koike, T. Kubo, S. Noguchi, M. Satoh, M. Sawabe, T. Shishido, A. Terashima, N. Toge, K. Ueno, K. Umemori, K. Watanabe, Y. Watanabe, S. Yamaguchi, A. Yamamoto, Y. Yamamoto, M. Yamanaka, K. Yokoya
KEK, Ibaraki, Japan
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
N. Kawabata, H. Nakamura, K. Nohara, M. Shinohara
SPS, Funabashi-shi, Japan
F. Yasuda
The University of Tokyo, Institute of Physics, Tokyo, Japan

We had been constructing a new facility for the fabrication of superconducting RF cavity at KEK from 2009 to 2011. In the facility, we have installed a deep-drawing machine, a half-cup trimming machine, an electron-beam welding machine, and a chemical etching room in one place. We started the studies on the fabrication of 9-cell cavity for International Linear Collier (ILC) using this facility. The studies are focusing on the cost reduction with keeping high performance of cavity, and the goal is the establishment of mass-production procedure for ILC. We already finished the fabrication of two 9-cell cavities in this facility. This article reports the current status of the studies.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI025

Export •

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

WEPRI030

Multipactor Simulation on Superconducting Spoke Cavity for Laser Compton Scattered Photon Sources

multipactoring, cavity, simulation, acceleration

2543

Y. Iwashita, H. Fujisawa, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
R. Hajima, R. Nagai, M. Sawamura
JAEA, Ibaraki-ken, Japan
T. Kubo
KEK, Ibaraki, Japan

Funding: This work is supported by Photon and Quantum Basic Research Coordinated Development Program.
Superconducting spoke cavity for laser Compton scattered (LCS) photon sources is under development. The operating frequency is 325-MHz to accelerate electron beam for the LCS sources, where the size of the spoke cavity is less than a elliptical cavities with the same frequency. Because of the complicated shape of the cavity, it may be suffered from a strong multipactor effect. The recent results on the multipactor analysis will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI030

Export •

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

WEPRI039

LIPAc SRF Linac Couplers Conditioning

vacuum, linac, SRF, operation

2562

D. Regidor, I. Kirpitchev, J. Mollá, P. Méndez, M. Weber, C. de la Morena
CIEMAT, Madrid, Spain
S. Chel, M. Desmons, G. Devanz, H. Jenhani
CEA/IRFU, Gif-sur-Yvette, France
H. Dzitko
CEA, Pontfaverger-Moronvilliers, France

The LIPAc SRF Linac is a cryomodule with eight superconducting HWR cavities at 175 MHz powered by RF couplers capable of transmitting up to 200 kW in CW. To prepare the couplers for operation, cleaning and high power RF processing are needed. When performed, the couplers will be ready for integration in the cryomodule. The Couplers Test Bench has been designed to perform the RF conditioning by pairs, providing good matching, low losses and the required UHV level. To preserve the cleanliness of the internal surfaces, after the test bench manufacturing, an ISO5 clean room has been used for the vacuum parts assembly. The size and number of particles was carefully controlled during the assembly process. The RF conditioning was performed at the IFMIF-EVEDA RF Integration Facility using the Prototype RF Module in travelling wave and standing wave modes. The process started with short pulses at low power and finished when full power CW was reached. Vacuum, multipacting, arcs and matching were continuously monitored to control the process avoiding damages. An overview of the process applied to the prototypes and the RF conditioning results are presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI039

Export •

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

WEPRI043

Implementation of Carbon Thin Film Coatings in the Super Proton Synchrotron (SPS) for Electron Cloud Mitigation

dipole, quadrupole, target, cathode

2574

P. Costa Pinto, T.C. Basso, A. Bellunato, P. Edwards, M. Mensi, A. Sublet, M. Taborelli
CERN, Geneva, Switzerland

Low Secondary Electron Yield (SEY) carbon thin films get rid of electron multipacting in accelerator beam pipes. Two magnetic cells of the SPS were coated with such material and installed. In total more than forty vacuum vessels and magnet interconnections were treated. The feasibility of the coating process was validated. The performance of the carbon thin film will be tested with LHC nominal beams after the end of the long shutdown 1. Particular attention will be drawn to the long term behaviour. This paper presents the sputtering techniques used to coat the different components; their characterization (SEY measurements on coupons, RF multipacting tests and pump down curves); and the technology to etch the carbon film in case of a faulty coating. The strategy to coat the entire SPS will also be exposed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI043

Export •

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

WEPRI044

Final Structure and Design Parameters of TARLA RF System

rf-amplifier, LLRF, controls, FEL

2577

Ö. Karslı, A.A. Aksoy, C. Kaya, İ.B. Koc, E.Ç. Polat, O. Yavaş
Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
M. Doğan
Dogus University, Istanbul, Turkey
S. Özkorucuklu
Istanbul University, Istanbul, Turkey

Funding: Work supported by Turkish Ministry of Development (Grant No: DPT2006K-120470)
Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) is an oscillator mode IR-FEL facility which is under construction since 2011. ELBE licensed superconducting modules housing TESLA RF cavities have been manufacturing for one year and the first module will be delivered in 2015. He Cryogenic System has also started to be manufacturing at similar time with the accelerator structures. It will be delivered in 2014. High Power RF amplifiers are started to tender procedures and delivery time is planning as 2015. The installation of high power transmission lines have to be completed at the same time with the delivery date of HPRF amplifiers to test the cavities and amplifiers. In this study, the final structural design of high power RF transmission lines and design parameters of RF amplifiers for TARLA is discussed.
On behalf of TARLA Collaboration, www.tarla.org.tr

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI044

Export •

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

WEPRI047

UK Industrial Development of Manufacturing Techniques for Superconducting RF Cavities

cavity, niobium, superconducting-RF, PLC

2586

A.E. Wheelhouse, R.K. Buckley, L.S. Cowie, P. Goudket, A.R. Goulden, P.A. McIntosh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
J.R. Everard, N. Shakespeare
Shakespeare Engineering, South Woodham Ferrers, Essex, United Kingdom

An STFC Innovation Partnership Scheme (IPS) grant, funding Daresbury Laboratory and Shakespeare Engineering Ltd to develop the capability to fabricate, process and test a 9-cell 1.3 GHz superconducting RF cavity in support of enabling UK industry to address the large potential market for superconducting RF structures. At the heart of the development are the repeatability and the reproducibility of the manufacturing process in an effort to reduce the costs. Effort has been spent on developing the techniques to fabricate the niobium half cells and the beam pipes and this paper discusses the manufacturing processes and the results obtained.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI047

Export •

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

WEPRI052

SRF Systems for ASTA at Fermilab

cavity, cryomodule, operation, SRF

2601

E.R. Harms, C.M. Baffes, K. Carlson, B. Chase, D.J. Crawford, E. Cullerton, D.R. Edstrom, M. Geynisman, A. Hocker, A.L. Klebaner, M.J. Kucera, J.R. Leibfritz, J.N. Makara, D. McDowell, S. Nagaitsev, O.A. Nezhevenko, D.J. Nicklaus, H. Pfeffer, Y.M. Pischalnikov, P.S. Prieto, J. Reid, W. Schappert, P. Stabile, P. Varghese
Fermilab, Batavia, Illinois, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The Advanced Superconducting Test Accelerator (ASTA) at Fermilab now being commissioned is comprised of a number of superconducting RF systems including single-cavity cryomodules and a TESLA/ILC style 8-cavity cryomodule. Two of them, 'Capture Cavity 2' and 'Cryomodule 2', have been cooled to 2 Kelvin and brought into operation. We provide an overview of the unique characteristics of each of the systems, commissioning experience, and latest results including their respective operating characteristics.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI052

Export •

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

WEPRI075

A Compact Beam Spreader using RF Deflecting Cavities for the LCLS-II

cavity, dipole, septum, HOM

2666

S.U. De Silva, J.R. Delayen, R.G. Olave
ODU, Norfolk, Virginia, USA
L.R. Doolittle, M. Placidi, A. Ratti
LBNL, Berkeley, California, USA
P. Emma
SLAC, Menlo Park, California, USA

The LCLS-II project currently under development is designed to accelerate electron bunches up to 4 GeV and transport them to one of two FEL undulators located more than 2 km downstream of the end of the LCLS-II linac. The upgrade requires a spreader system to separate the baseline electron bunches and transport them to two undulator lines or a local dump. Fast bipolar kickers (FK) or transverse electric rf deflectors (RFD) are considered as fast-switching devices (FSD). In the RFD approach described here three design options operating at 325 MHz are studied including a superconducting rf-dipole cavity, a normal conducting rf-dipole cavity, and a normal conducting 4-rod cavity. Optional compact splitting schemes involving a combination of vertical and horizontal initial deflections are addressed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI075

Export •

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

WEPRI077

Cryogenic Test of a 750 MHz Superconducting RF Dipole Crabbing Cavity*

cavity, radiation, simulation, cryogenics

2672

A. Castilla, J.R. Delayen
ODU, Norfolk, Virginia, USA
A. Castilla, J.R. Delayen, H. Park
JLab, Newport News, Virginia, USA
A. Castilla
DCI-UG, León, Mexico

Funding: *Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. With resources of NERSC, under U.S. DOE contract No. DE-AC02-05CH11231.
A superconducting rf dipole cavity has been designed to address the challenges of a high repetition rate (750 MHz), high current for both electron/ion species (0.5/3 A per bunch), and large crossing angle (50 mrad) at the interaction points (IPs) crabbing system for the Medium Energy Electron-Ion Collider (MEIC) proposed by Jefferson Lab. The cavity prototype built at Niowave, Inc. has been tested at the Jefferson Lab facilities. In this work we present a detailed analysis of the prototype cavity performance at 4 K and 2 K, corroborating the absence of hard multipacting barriers that could limit the desired transverse fields, along with the surface resistance (R_s) temperature dependency.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI077

Export •

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

WEPRI081

Mechanical Design of the 704 MHz 5-cell SRF Cavity Cold Mass for CeC PoP Experiment

cavity, SRF, cryomodule, experiment

2678

J.C. Brutus, S.A. Belomestnykh, I. Ben-Zvi, Y. Huang, V. Litvinenko, I. Pinayev, J. Skaritka, L. Snydstrup, R. Than, J.E. Tuozzolo, W. Xu
BNL, Upton, Long Island, New York, USA
T.L. Grimm, R. Jecks, J.A. Yancey
Niowave, Inc., Lansing, Michigan, USA

Funding: * Work is supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the US DOE.
A 5-cell SRF cavity operating at 704 MHz will be used for the Coherent Electron Cooling Proof of Principle (CeC PoP) system under development for the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The CeC PoP experiment will demonstrate the new technique of cooling proton and ion beams that may increase the beam luminosity in certain cases, by as much as tenfold. The 704 MHz cavity will accelerate 2 MeV electrons from a 112 MHz SRF gun up 22 MeV. Novel mechanical designs, including a super fluid heat exchanger, helium vessel, vacuum vessel and tuner mechanism are presented. Structural and thermal analysis, using ANSYS were performed to confirm the mechanical tuning system structural stability. This paper provides an overview of the design, the project status and schedule of the 704 MHz 5-cell SRF for CeC PoP experiment.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI081

Export •

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

WEPRI085

The Elettra 3.5 T Superconducting Wiggler Refurbishment

wiggler, vacuum, controls, storage-ring

2687

D. Zangrando, R. Bracco, D. Castronovo, M. Cautero, E. Karantzoulis, S. Krecic, G.L. Loda, D. Millo, L. Pivetta, G. Scalamera, R. Visintini
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
S.V. Khrushchev, N.A. Mezentsev, V.A. Shkaruba, V.M. Syrovatin, O.A. Tarasenko, V.M. Tsukanov, A.A. Volkov
BINP SB RAS, Novosibirsk, Russia

A 3.5 Tesla 64 mm period superconducting wiggler (SCW) was constructed by the Russian Budker Institute of Novosibirsk (BINP) and installed in the Elettra storage ring as a photon source for the second X-ray diffraction beamline in November 2002, but never used due to the lack of the funding required for the beamline construction. About three years ago, the beamline construction was finally funded together with the refurbishment of the SCW. This upgrade, that was necessary in order to make the SCW operations compatible with the top up mode of the storage ring aimed in a drastic reduction of the liquid helium consumption by means of replacing the cryostat with a new version. At the same time the upgrade aimed as well to improve the reliability of the cryostat, to update the control system and to verify the magnetic field performance after a very long time of inactivity. In this paper we present and discuss the performances of the SCW following its refurbishment carried out by BINP team and its re-commissioning in the Elettra storage ring.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI085

Export •

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

WEPRI096

Mu2e Magnetic Measurements

solenoid, detector, target, experiment

2719

M. Buehler, M.A. Tartaglia, J.C. Tompkins
Fermilab, Batavia, Illinois, USA
C.R. Orozco
University of Illinois at Urbana-Champaign, Illinois, USA

The Mu2e experiment at Fermilab is designed to explore charged lepton flavor violation by searching for muon-to-electron conversion. The magnetic field generated by a system of solenoids is crucial for Mu2e and requires accurate characterization to detect any flaws and to produce a detailed field map. Stringent physics goals are driving magnetic field specifications for the Mu2e solenoids. A field mapper is being designed, which will produce detailed magnetic field maps. The uniform field region of the spectrometer volume requires the highest level of precision (1 Gauss per 1 Tesla). During commissioning, multiple magnetic field maps will be generated to verify proper alignment of all magnet coils, and to create the final magnetic field map. In order to design and build a precise field mapping system consisting of Hall and NRM probes, tolerances and precision for such a system need to be evaluated. In this paper we present a design for the Mu2e field mapping hardware, and discuss results from OPERA-3D simulations to specify parameters for Hall and NMR probes. We also present a fitting procedure for the analytical treatment of our expected magnetic measurements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI096

Export •

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

WEPRI107

Fundamental Thermal Analysis for Cryogenic System Design

radiation, cavity, cryogenics, cryomodule

2749

H. Kim, D. Jeon, W.K. Kim, G.-T. Park, I. Shin, J.H. Shin, S.W. Yoon
IBS, Daejeon, Republic of Korea

Non-uniform temperature distribution, surface roughness, and superfluid helium level change between 2K dewar and cryomodule are most important thermal analyses in designing cryogenic system. Effective temperature for non-uniform temperature distribution is defined. Thermal radiation property from surface roughness which is related to fractional dimension is investigated. Superfluid helium level change between 2K dewar and cryomodule is shown as a function of temperature difference. Our research can be useful thermal analyses for cryogenic system design.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI107

Export •

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

THOAA01

Beam Trip Analysis by Bunch-by-bunch BPM System in BEPCⅡ

storage-ring, controls, positron, resonance

2779

Q.Y. Deng, J.S. Cao, J. Yue
IHEP, Beijing, People's Republic of China

A new bunch-by-bunch beam position measurement prototype system has been designed and built to monitor and analysis beam trip in the BEPCⅡ(Beijing Electron-Positron ColliderⅡ) machine. The fast ADC and programmable FPGA can obtain the beam information bunch-by-bunch, so we can analyze base on both time domain and frequency domain. In this paper we will presentation the system architecture and discuss some beam trip analysis result, such as beam instability, tune drifting, RF breakdown, and so on.

Slides THOAA01 [0.999 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THOAA01

Export •

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

THYA01

Control and Application of Beam Microbunching in High Brightness Linac-driven Free Electron Lasers

laser, FEL, impedance, radiation

2789

G.V. Stupakov
SLAC, Menlo Park, California, USA

The remarkable properties of coherent radiation from free-electron lasers (FELs) are due to the current modulation in the beam with the modulation period equal to the radiation wavelength. This modulation is developed as a result of a beam instability when the beam propagates in a long FEL undulator, and requires a beam with a high-peak current, small emittance and a small energy spread. Unfortunately the same beam qualities make it a subject to a so-called microbunching instability at a much longer scale than the radiation wavelength. It is driven by the space charge and CSR impedances in the machine and develops during the beam acceleration in the linac, compression, and transport to the undulator. If not controlled, the microbunching instability influences dramatically the FEL performance and in the worst case can even ruin the lasing. In the presentation we will review the mechanism behind the microbunching instability, the suppression methods used in existing facilities as well as possible future developments and concepts.

Slides THYA01 [5.631 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THYA01

Export •

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

THOBA03

Beam Transport System from a Laser Wakefield Accelerator to a Transverse Gradient Undulator

undulator, laser, beam-transport, radiation

2803

C. Widmann, V. Afonso Rodríguez, A. Bernhard, N. Braun, A.-S. Müller, A.I. Papash, R. Rossmanith, W. Werner
KIT, Karlsruhe, Germany
M. Kaluza, M. Reuter
HIJ, Jena, Germany
M. Kaluza, M. Nicolai, A. Sävert
IOQ, Jena, Germany

Funding: This work is funded by the German Federal Ministry for Education and Research under contract no. 05K10VK2.
The transport and matching of electron beams generated by a laser wakefield accelerator (LWFA) is a major challenge due to their large energy spread and divergence. Strong focussing magnets and a chromatic correction are required. This contribution discusses the layout of the beam transport optics for a diagnostic beamline at the LWFA in Jena, Germany. The aim of this optics is to match the betatron functions and the dispersion to the field of a transverse gradient undulator (TGU) such that monochromatic undulator radiation is generated despite the large energy spread.

Slides THOBA03 [2.891 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THOBA03

Export •

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

THOAB03

A High Resolution Spatial-temporal Imaging Diagnostic for High Energy Density Physics Experiments

target, scattering, proton, diagnostics

2819

W. Gai
ANL, Argonne, Illinois, USA
S. Cao, H.S. Xu, W.-L. Zhan, Z.M. Zhang, Y.T. Zhao
IMP, Lanzhou, People's Republic of China
J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA
C.-X. Tang
TUB, Beijing, People's Republic of China

We present a scheme that uses a high energy electron beam as a probe for time resolved (~ pico – nano seconds) imaging measurements of high energy density processes in materials with spatial resolution of < 1 μm. The device uses an electron bunch train with a flexible time structure penetrating a time varying high density target. By imaging the scattered electron beam, the detailed target profile and its density evolution can be accurately determined. In this paper, we discuss the viability of the concept and show that for densities in the range up to 400 gram/cm³, an electron beam consisting of a train of ~800 MeV bunchlets, each a few ps long and with charges ~nC is suitable. Successful demonstration of this concept will have a major impact for both future fusion science and HEDP physics research.

Slides THOAB03 [2.493 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THOAB03

Export •

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

THOBB03

Novel Device for In-situ Thick Coatings of Long, Small Diameter Accelerator Vacuum Tubes

cathode, vacuum, target, plasma

2834

A. Hershcovitch, M. Blaskiewicz, J.M. Brennan, W. Fischer, C.J. Liaw, W. Meng, R.J. Todd
BNL, Upton, Long Island, New York, USA
A.X. Custer, A.A. Dingus, M.Y. Erickson, N.Z. Jamshidi, R.R. Laping, H.J. Poole
PVI, Oxnard, California, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
To alleviate the problems of unacceptable ohmic heating and of electron clouds, a 50 cm long cathode magnetron mole was fabricated and successfully operated to copper coat an assembly containing a full-size stainless steel cold bore RHIC magnet tubing connected to two types of RHIC bellows, to which two additional RHIC tubing pipes were connected. To increase cathode lifetime, movable magnet package was developed, and thickest possible cathode was made, with rather challenging target to substrate distance of less than 1.5 cm. The magnetron is mounted on a carriage with spring loaded wheels that successfully crossed bellows and adjusted for variations in vacuum tube diameter, while keeping the magnetron centered. Electrical power and cooling water are fed through a motorized spool driven umbilical cabling system, which is enclosed in a flexible braided metal sleeve. Optimized process to ensure excellent adhesion was developed. Coating adhesion of 10 μm Cu surpassed all industrial tests; exceeded maximum capability of a 12 kg pull test fixture. Details of experimental setup for coating two types of bellows and a full-scale magnet tube sandwiched between them will be presented.

Slides THOBB03 [2.033 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THOBB03

Export •

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

THPPA00

EPS-AG Prize d) Presentation

cryogenics, operation, simulation, synchrotron

2837

J.F. Esteban Müller
EPFL, Lausanne, Switzerland
J.F. Esteban Müller
CERN, Geneva, Switzerland

EPS-AG Prize d) Presentation. The Prize d) winner will present the work for which the prize is awarded, on the basis of the judging by the EPS-AG Prizes Selectin Committee.

Slides THPPA00 [3.432 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPPA00

Export •

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

THPPA01

FEL R&D Initiatives at the SLAC National Accelerator Laboratory

undulator, FEL, laser, free-electron-laser

2842

A. Marinelli
SLAC, Menlo Park, California, USA

The successful lasing of the linac coherent light source in 2009, the first x-ray free-electron laser (xFEL) in the world, has opened a new era for x-ray photon science. The unprecedented intensity and coherence of the LCLS photon pulses have enabled groundbreaking experiments in a wide variety of fields ranging from coherent x-ray imaging to molecular and atomic physics. Despite the success of x-ray free-electron lasers, there is a steady push to extend and improve their capabilities fueled by the users' demands for new modes of operation and more precise photon and electron diagnostics. In my talk I will present several R&D initiatives at the SLAC National Accelerator Laboratory geared towards improving the performance and extending the capabilities of x-ray FELs. In particular I will focus on the spectral manipulation of FELs and our recent development of the multibunch and multicolor x-ray FEL modes at LCLS as well as our demonstration of the longitudinal space-charge amplifier as a broadband coherent light source at the NLCTA test accelerator.

Slides THPPA01 [10.793 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPPA01

Export •

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

THPPA02

Gersch Budker Prize Presentation

klystron, collider, linear-collider, FEL

2846

T. Shintake
OIST, Onna-son, Okinawa, Japan

SACLA: SPring-8 Angstrom Compact free-electron Laser, previously called XFEL/SPring-8, which is based on electron accelerator technology developed at SCSS project, in which C-band high gradient linear accelerator provides stable driving beams. Looking back upon 20 years R&D on C-band accelerator, I would like to give some advises to young scientists on doing research. The developed C-band accelerator is now providing 8 GeV electron beams at SACLA X-ray FEL in daily operation with the world best energy stability among these large scale machines.

Slides THPPA02 [17.649 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPPA02

Export •

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

THPPA03

The MAX-lab Story; From Microtron to MAX IV

microtron, synchrotron, storage-ring, synchrotron-radiation

2852

M. Eriksson
MAX-lab, Lund, Sweden

The MAX story started with the design and construction of a small Race-Track Microtron 1973-1979. This microtron was later followed by the synchrotron radiation storage rings MAX I, MAX II, MAX III and the MAX IV facility, the latter consisting of two storage rings operated at 1.5 and 3 Gev respectively and also including a full energy injector linac. It was quite clear from the very beginning that conventional accelerator technology not was matching the boundary conditions in terms of the staff size and limited economical resources at MAX. We had to find new technical solutions based on mass-produced industrial components and an extensive usage of CNC machining to match the turbulent development of synchrotron radiation sources. This article describes some of the most important features of the accelerators developed at MAX-lab and covers also the design philosophy behind the early ideas for designing a close to Diffraction Limited Storage Ring. Finally, the author and MAX staff wants to thank the prize committee for the prestigious Wideröe prize and thank all our international colleagues world-wide.

Slides THPPA03 [3.396 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPPA03

Export •

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

THPRO003

Progress of the LUNEX5 demonstator Project

FEL, operation, undulator, laser

2856

M.-E. Couprie, C. Benabderrahmane, P. Berteaud, C. Bourassin-Bouchet, F. Bouvet, L. Cassinari, L. Chapuis, J. Daillant, M. Diop, M.E. El Ajjouri, C. Evain, C. Herbeaux, N. Hubert, M. Labat, P. Lebasque, A. Lestrade, A. Loulergue, P. Marchand, O. Marcouillé, J.L. Marlats, C. Miron, P. Morin, A. Nadji, F. Polack, F. Ribeiro, J.P. Ricaud, P. Roy, K. Tavakoli, M. Valléau, D. Zerbib
SOLEIL, Gif-sur-Yvette, France
S. Bielawski, E. Roussel, C. Szwaj
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
B. Carré, D. Garzella
CEA/DSM/DRECAM/SPAM, Gif-sur-Yvette, France
X. Davoine
CEA/DAM/DIF, Arpajon, France
N. Delerue
LAL, Orsay, France
G. Devanz
CEA/DSM/IRFU, France
A. Dubois, J. Lüning
CCPMR, Paris, France
G. Lambert, R. Lehé, V. Malka, A. Rousse, C. Thaury
LOA, Palaiseau, France
C. Madec, A. Mosnier
CEA/IRFU, Gif-sur-Yvette, France

LUNEX5 (free electron Laser Using a New accelerator for the Exploitation of X-ray radiation of 5th generation) aims at investigating the production of short, intense, coherent pulses in the 40-4 nm spectral range [1]. It comprises two types of accelerators connected to a single Free Electron Laser (FEL) for advanced seeding configurations (seeding with High order Harmonic in Gas, echo). A 400 MeV superconducting Linear Accelerator, adapted for studies of advanced FEL schemes, will enable future upgrade towards high repetition rate and multi-user operation by splitting part of the macropulse to different FEL lines. A 0.4 - 1 GeV Laser Wake Field Accelerator (LWFA) [2] will also be qualified by the FEL application. After the Conceptual Design Report, R&D has been launched on different sub components. Following transport theoretical studies of longitudinal and transverse manipulation of a LWFA electron beam enabling to provide theoretical amplification, a test experiment is under preparation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO003

Export •

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

THPRO009

Harmonic Lasing in X-ray FELs

undulator, FEL, photon, operation

2873

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

Contrary to nonlinear harmonic generation, harmonic lasing in a high-gain FEL can provide much more intense, stable, and narrow-band FEL beam which is easier to handle if the fundamental is suppressed. We perform a parametrization of the solution of eigenvalue equation for lasing at odd harmonics, and present explicit expression for FEL gain length, taking into account all essential effects. We propose and discuss methods for suppression of the fundamental. We also suggest a combined use of harmonic lasing and lasing at the retuned fundamental wavelength in order to reduce bandwidth and to increase brilliance of X-ray beam. We discover that in a part of the parameter space, corresponding to the operating range of soft X-ray beamlines of X-ray FEL facilities, harmonics can grow faster than the fundamental. We suggest that harmonic lasing can be widely used in the existing or planned X-ray FEL facilities. LCLS after a minor modification can lase at the 3rd harmonic up to the photon energy of 25-30 keV providing multi-gigawatt power level. At the European XFEL the harmonic lasing would allow to extend operating range up to 100 keV, to reduce bandwidth and increase brilliance.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO009

Export •

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

THPRO010

Analysis of Operation of Harmonic Lasing Self-seeded FEL

undulator, FEL, simulation, radiation

2876

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

Harmonic lasing self-seeded FEL holds great potential for significant improvement of the the longitudinal coherence of the radiation. A gap-tunable undulator is divided into two parts by setting two different undulator parameters such that the first part is tuned to a sub-harmonic of the second part. Harmonic lasing occurs in the exponential gain regime in the first part of the undulator, also the fundamental stays well below saturation. In the second part of the undulator the fundamental mode is resonant to the wavelength, previously amplified as the harmonic. The amplification process proceeds in the fundamental mode up to saturation. In this case the bandwidth is defined by the harmonic lasing (i.e. it is reduced by a significant factor depending on harmonic number) but the saturation power is still as high as in the reference case of lasing at the fundamental in the whole undulator, i.e. the spectral brightness increases. Application of the undulator tapering in the deep nonlinear regime would allow to generate higher peak powers approaching TW level. The scheme is illustrated with the parameters of the European XFEL.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO010

Export •

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

THPRO011

Investigation of the Coherence Properties of the Radiation at FLASH

radiation, emittance, FEL, undulator

2879

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

We present the results of the studies of coherence properties of the radiation from FLASH for fundamental harmonic and higher odd harmonics. General overview of the parameter space is performed including peak current, emittance, and external focusing. The results of our studies show that present configuration of FLASH free electron laser is not optimal for providing ultimate quality of the output radiation. We find that the physical origin of the problem is mode degeneration. The way for improving quality of the radiation is proposed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO011

Export •

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

THPRO012

Wakefield-based Dechirper Structures for ELBE

wakefield, vacuum, radiation, controls

2882

F. Reimann, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
U. Lehnert, P. Michel
HZDR, Dresden, Germany

Funding: Federal Ministry of Education and Research
The efficient reduction of the pulse length and the energy width of electron beams plays a crucial role in the generation of short pulses in the range of sub-picoseconds at future light sources. At the radiation source ELBE in Dresden Rossendorf short pulses are required for coherent THz generation and laser-electron beam interaction experiments such as X-ray Thomson scattering. Energy dechirping can be carried out passively by wakefields generated when the electron beam passes through suitable structures, namely corrugated and dielectrically lined cylindrical pipes or dielectrically lined rectangular waveguides (*,**,***). All structures offer the possibility to tune the resulting wakefield and therefore the resulting energy chirp through a variation of purely geometrical or material parameters. In this paper we present a semi-analytical approach to determine the wakefield in dielectrically lined rectangular waveguide, starting with the expression of the electric field in terms of the structure's eigenmodes.
* Bane, Stupakov, SLAC-PUB-14925 (2012)
** Mosnier, Novokhatski, in: Proceedings of PAC97, Vancouver, Canada, 1997
*** Antipov et al., in: Proceedings of IPAC2012, New Orleans, USA, 2012

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO012

Export •

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

THPRO013

FERMI Status Report

FEL, laser, linac, experiment

2885

M. Svandrlik, E. Allaria, F. Bencivenga, C. Callegari, F. Capotondi, D. Castronovo, 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, A. Fabris, R. Fabris, W.M. Fawley, M. Ferianis, E. Ferrari, P. Finetti, L. Fröhlich, P. Furlan Radivo, G. Gaio, D. Gauthier, F. Gelmetti, L. Giannessi, M. Kiskinova, S. Krecic, M. Lonza, N. Mahne, C. Masciovecchio, M. Milloch, F. Parmigiani, G. Penco, L. Pivetta, O. Plekan, M. Predonzani, E. Principi, L. Raimondi, P. Rebernik Ribič, F. Rossi, L. Rumiz, C. Scafuri, C. Serpico, P. Sigalotti, C. Spezzani, C. Svetina, M. Trovò, A. Vascotto, M. Veronese, R. Visintini, D. Zangrando, M. Zangrando
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

FERMI, the seeded Free Electron Laser (FEL) located at the Elettra laboratory in Trieste, Italy, consists of two FEL lines. The FEL-1 facility, covering the wavelength range between 20 and 100 nm, was officially opened to external users. The shorter wavelength range, between 20 and 4 nm, is covered by the FEL-2 line, a double stage cascade operating in the “fresh bunch injection” mode, which is still under commissioning. We will report on the different FEL-1 operation modes that can be offered for users and assess the performance of the facility. The progress in the commissioning of FEL-2 will then be addressed, in particular reporting the performance attained at the lower wavelength limit; this aspect is of great interest for the user’s community of the FERMI seeded FEL since it allows to carry out experiments below the carbon K-edge.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO013

Export •

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

THPRO016

Stable Generation of High Power Self-seeded XFEL at SACLA

radiation, undulator, photon, FEL

2888

T. Inagaki, N. Adumi, T. Fukui, T. Hara, Y. Inubushi, T. Ishikawa, H. Kimura, R. Kinjo, H. Maesaka, Y. Otake, H. Tanaka, T. Tanaka, K. Togawa, M. Yabashi
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
S. Goto, T.K. Kameshima, T. Ohata, K. Tono
JASRI/SPring-8, Hyogo, Japan
T. Hasegawa, S. Tanaka
SES, Hyogo-pref., Japan
A. Miura, H. Ohashi, H. Yamazaki
Japan Synchrotron Radiation Research Institute (JASRI/SPring-8), Hyogo, Japan

A self-seeded XFEL system using a transmitted beam under Bragg diffraction has been developed at the first compact XFEL facility SACLA in order to generate a brilliant single-mode XFEL with high temporal coherence. High stability and unique beam characteristics of SACLA should significantly contribute to achieve reliable, high-quality seeded XFEL operation. In particular, the short-pulse property that has been achieved in routine operation enables us to switch SASE and seeded mode quickly, without changing the electron beam parameters. This is also useful for delivering different modes to multiple beamlines simultaneously. In the test experiments carried out in autumn 2013, spectral narrowing was observed at 10 keV using diamond 400 reflection. Systematic optimization on beam properties is now in progress towards experimental use of seeded XFELs in summer 2014. This talk gives the overview of the plan, achieved results and ongoing R&D.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO016

Export •

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

THPRO018

Electron-Magnetic-Phase Mixing in a Linac-driven FEL to Suppress Microbunching in the Optical Regime and Below

linac, FEL, laser, radiation

2894

S. Di Mitri, S. Spampinati
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
H.-S. Kang
PAL, Pohang, Kyungbuk, Republic of Korea
S. Spampinati
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Control of microbunching instability is a fundamental requirement in modern high brightness electron linacs, in order to prevent malfunction of beam optical diagnostics and contamination in the generation of coherent radiation, such as free electron lasers. We present experimental control and suppression of microbunching instability-induced optical transition radiation by means of particles’ longitudinal phase mixing in a magnetic chicane*. In presence of phase mixing, the intensity of the beam-emitted coherent optical transition radiation is reduced by one order of magnitude and brought to the same level provided, alternatively, by beam heating. The experimental results are in agreement with particle tracking and analytical evaluations of the instability gain. A discussion of applications of magnetic phase mixing to the generation of quasi-cold high-brightness ultra-relativistic electron beams is finally given.
* S. Di Mitri and S. Spampinati, Phys. Rev. Lett. 112, 134802 (2014)

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO018

Export •

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

THPRO022

JINR Powerful Laser Driver Applied for FEL Photoinjector

laser, radiation, FEL, ion

2906

E. Syresin, N. Balalykin, M.A. Nozdrin, G. Shirkov, G.V. Trubnikov
JINR, Dubna, Moscow Region, Russia
E. Gacheva, E. Khazanov, G. Luchinin, S. Mironov, A. Poteomkin, V. Zelenogorsky
IAP/RAS, Nizhny Novgorod, Russia

Funding: The work is funded by the German Federal Ministry of education and Research, project 05K10CHE.
The JINR develops a project of superconducting linear accelerator complex, based on a superconducting linear accelerator, for applications in nanoindustry, mainly for extreme ultraviolet lithography at a wavelength of 13.5 nm using kW-scale Free Electron Laser (FEL) light source. The application of kW-scale FEL source permits realizing EUV lithography with 22 nm, 16 nm resolutions and beyond. JINR-IAP collaboration constructed powerful laser driver applied for photoinjector of FEL linear accelerator which can be used for EUV lithography. To provide FEL kW-scale EUV radiation the photoinjector laser driver should provide a high macropulse repetition rate of 10 Hz, a long macropulse time duration of 0.8 ms and 8000 pulses per macropulse. The laser driver operates at wavelength of 260-266 nm on forth harmonic in the mode locking on base of Nd ions or Yb ions The laser driver micropulse energy of 1.6 uJ should provide formation of electron beam in FEL photoinjector with the bunch charge about 1 nC.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO022

Export •

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

THPRO023

Methods for the Optimization of a Tapered Free-Electron Laser

wiggler, radiation, FEL, simulation

2909

A.W.L. Mak, F. Curbis, S. Werin
MAX-lab, Lund, Sweden

In a free-electron laser (FEL), the technique of wiggler tapering enables the sustained growth of radiation power beyond the initial saturation. With the goal to develop an X-ray FEL in the terawatt power regime, it is important to utilize this technique and optimize the taper profile, giving the wiggler parameter as a function of the distance along the wiggler line. This work examines two methods of optimization, which are based on the theoretical analysis by Kroll, Morton and Rosenbluth (KMR). Using the numerical simulation code GENESIS, the methods are applied to a case for the possible future FEL at the MAX IV Laboratory in Lund, Sweden, as well as a case for the LCLS-II.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO023

Export •

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

THPRO024

Progress of the EU-XFEL Laser Heater

laser, undulator, vacuum, photon

2912

M. Hamberg, V.G. Ziemann
Uppsala University, Uppsala, Sweden

Funding: Swedish research council under Project number DNR-828-2008-1093 for financial support.
We describe the technical layout and report the status of the installation of the undulator, optical and vacuum systems of the laser heater for the EUXFEL. The laser heater is a device to increase the overall X-ray brightness stability. This is achieved by an optical laser system which induce an additional momentum spread in the electron bunches to reduce micro-bunching instabilities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO024

Export •

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

THPRO026

Design Parameters and Current Status of the TARLA Project

FEL, undulator, linac, radiation

2918

A.A. Aksoy, Ö. Karslı, C. Kaya, E. Kazancı, O. Yavaş
Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
P. Arıkan
Gazi University, Faculty of Arts and Sciences, Teknikokullar, Ankara, Turkey
S. Özkorucuklu
Istanbul University, Istanbul, Turkey

Funding: Work is supported by Ministry of Development of Turkey with Grand No: DPT2006K-120470
The Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) will operate two InfraRed Free Electron Lasers (IR-FEL) covering the range of 3-250 microns. The facility will consist of an injector fed by a thermionic triode gun with two-stage RF bunch compression, two superconducting accelerating ELBE modules operating at continuous wave (CW) mode and two independent optical resonator systems with different undulator period lengths. The electron beam will also be used to generate Bremsstrahlung radiation. In this paper, we discuss design goals of the project and present status and road map of the project.
On behalf of TARLA Team

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO026

Export •

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

THPRO027

Turkish Accelerator Center: The Status and Roadmap

FEL, linac, proton, factory

2921

A.A. Aksoy, O. Yavaş, H.D. Duran Yıldız
Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
B. Akkus, S. Özkorucuklu, L.S. Yalcin
Istanbul University, Istanbul, Turkey
H. Aksakal, Z. Nergiz
Nigde University, Nigde University Science & Art Faculty, Nigde, Turkey
E. Algin
Eskisehir Osmangazi University, Eskisehir, Turkey
O. Cakir
Ankara University, Faculty of Sciences, Ankara, Turkey

Funding: Ankara University
Turkish Accelerator Center (TAC) Project has started with support of the Ministry of Development (MD) of Turkey under the coordination of Ankara University. TAC is an inter-university collaboration with 12 Turkish Universities. An IR FEL facility (TARLA) based on Sc linac with 15-40 MeV energy under construction in Ankara as the first facility of TAC. It is expected that the TARLA facility will be commissioning in 2017. In addition to the TARLA, it is planned that Turkish Accelerator Center will include a third generation synchrotron radiation facility based on 1-3 GeV electron synchrotron (TAC SR), a fourth generation SASE FEL facility based on up to 5 GeV electron linac (TAC SASE FEL), a multi-purpose proton accelerator facility with 3 MeV-2 GeV beam energy (TAC PAF) and an electron-positron collider as a super charm factory (TAC PF). Construction phase of the proposed GeV scale accelerator facilities will cover next decade. In this presentation, main goals and road map of Turkish Accelerator Center will be explained. (http://thm.ankara.edu.tr)
*On behalf of TAC collaboration

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO027

Export •

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

THPRO030

Developments in CLARA Accelerator Design and Simulations

FEL, wakefield, simulation, undulator

2930

S. Spampinati
Cockcroft Institute, Warrington, Cheshire, United Kingdom
D. Angal-Kalinin, A.D. Brynes, D.J. Dunning, J.K. Jones, K.B. Marinov, J.W. McKenzie, B.L. Militsyn, N. Thompson, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
I.P.S. Martin
DLS, Oxfordshire, United Kingdom

We present recent developments in the accelerator design of CLARA (Compact Linear Accelerator for Research and Applications), the proposed UK FEL test facility at Daresbury Laboratory. Updates on the electron beam simulations and code comparisons including wakefields are described. Simulations of the effects of geometric wakefields in the small-aperture FEL undulator are shown, as well as further simulations on potential FEL experiments using chirped beams. We also present the results of simulations on post-FEL diagnostics.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO030

Export •

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

THPRO032

Studies on LPWA-based Light Sources driven by a Transverse Gradient Undulator

undulator, FEL, laser, simulation

2937

T. Chanwattana, R. Bartolini, A. Seryi
JAI, Oxford, United Kingdom
R. Bartolini
DLS, Oxfordshire, United Kingdom

The Accelerator Science Laboratory (ASL) is under development at the John Adams Institute in Oxford with the aim of fostering advanced accelerator concepts and applications. The option to install a LPWA based light source driven by a transverse gradient undulator is being investigated. This report presents the accelerator physics, FEL studies and the performance expected from such a facility.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO032

Export •

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

THPRO033

Electron-bunch Shaping for Coherent Compton Scattering

laser, radiation, simulation, scattering

4107

J.E. Thorne, P. Piot, I. Viti
Northern Illinois University, DeKalb, Illinois, USA
P. Piot
Fermilab, Batavia, Illinois, USA

Producing high-quality x rays could have important applications to high-precision medical imaging and national security. Inverse Compton scattering involving the head-on collision of a relativistic electron bunch with a high-power laser offers a viable path toward the realization of a compact x-ray source. A method consisting in reflecting a short-pulse laser onto a “relativistic mirror” (a moving thin sheet of electrons) has been proposed and recently demonstrated as a way to enhance the back-scattered photon flux by operating in the coherent regime. In this contribution we present particle-in-cell numerical simulations of the inverse Compton scattering process and especially investigate the impact of the laser-pulse and electron-beam distributions that could substantially improve the x-ray production via coherent emission.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO033

Export •

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

THPRO034

Design of the LCLS-II Electron Optics

undulator, linac, quadrupole, optics

2940

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

Funding: Work supported by the US Department of Energy Contract DE-AC02-76SF00515.
The LCLS-II project is a high repetition rate, high average brightness free-electron laser based on the existing facilities at the SLAC National Accelerator Laboratory. The LCLS-II will be driven by a new CW superconducting RF (SCRF) 4-GeV linac replacing the existing Cu-linac in the 1st km of the linac tunnel. The SCRF linac will include chicanes for providing full compression of the electron bunch length. After the linac, the electron beam will be directed into the existing 2-km bypass line connecting to the Beam Switch Yard (BSY), where a new spreader system will allow a high rate bunch-by-bunch deflection into the hard X-ray (HXR) or soft X-ray (SXR) transport lines, or towards the BSY high power dump. The HXR line will include a new variable gap undulator replacing the existing LCLS-I undulator and will reuse the existing LCLS-I linac-to-undulator and dump transport lines. The SXR will require a new transport line sharing the same tunnel with the HXR and will include a new variable gap undulator. Overview of the electron beam transport and the optics design are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO034

Export •

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

THPRO038

Energy-Silenced HGHG

laser, FEL, bunching, space-charge

2946

E. Hemsing, G. Marcus, A. Marinelli
SLAC, Menlo Park, California, USA
D. Xiang
Shanghai Jiao Tong University, Shanghai, People's Republic of China

We study the effect of longitudinal space charge on the correlated energy spread of a relativistic beam that has been microbunched for the emission of high harmonic radiation. We show that, in the case of microbunching induced by a laser modulator followed by a dispersive chicane, longitudinal space charge forces can act to significantly reduce the induced energy spread of the beam without a reduction in the harmonic bunching content. This effect may significantly relax constraints on the harmonic number achievable in HGHG FELs, which are otherwise limited by the induced energy spread from the laser.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO038

Export •

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

THPRO039

Model-independent Description of Shot-noise, Amplification and Saturation

FEL, bunching, undulator, simulation

2949

Y.C. Jing, V. Litvinenko, G. Wang
BNL, Upton, Long Island, New York, USA
V. Litvinenko
Stony Brook University, Stony Brook, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
High-gain FEL is one of many electron-beam instabilities, which have a number of common features linking the shot noise, the amplification and the saturation. In this paper we present a new, model-independent description of the interplay between these effects and derivation of a simple formula determining the saturation and maximum attainable gain in such instabilities. Application of this model-independent formula to FEL is compared with FEL theory and simulations. We describe limitations resulting from these finding for FEL amplifiers used for seeded FELs and for Coherent electron Cooling.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO039

Export •

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

THPRO041

Position of Maximum in Quantum Spectrum of Synchrotron Radiation

radiation, polarization, synchrotron, synchrotron-radiation

2952

A.N. Burimova, D.M. Gitman
IFUSP, Sao Paulo, Brazil
V.G. Bagrov
Institute of High Current Electronics, Tomsk, Russia

Funding: FAPESP
In the framework of quantum theory, we consider the condition for radiation maximum shift between harmonics of SR spectrum for scalar and spinor particles. Since quantum spectrum is discrete and finite, one can find values of radiation parameters such that the maximum in radiation spectrum stays at highest harmonic. It turns out that there exists a "quantization" of magnetic field associated with shift of maximum from one harmonic to another.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO041

Export •

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

THPRO042

Field Emission Studies of Heat Treated Mo Substrates

SRF, cathode, gun, cavity

2955

R. Barday, A. Jankowiak, T. Kamps, C. Klimm, J. Knobloch, F. Siewert, A. Varykhalov
HZB, Berlin, Germany
S. Lagotzky, G. Müller
Bergische Universität Wuppertal, Wuppertal, Germany
B. Senkovskiy
Technische Universität Dresden, Dresden, Germany

Funding: This work was supported by German Bundesministerium für Bildung und Forschung project 05K13PX2, Land Berlin and grants of Helmholtz Association.
Molybdenum can be used as a substrate for the bi-alkali antimonide photocathodes utilized for the generation of high brightness electron beams in a superconducting radio frequency (SRF) photoinjector cavities. Operation at high field strength is required to obtain a low emittance beam, thus increasing the probability of field emission (FE) from the cathode surface. Usually, substrates are heated in situ before alkali de- position to remove oxide layers from the surface. FE on Mo substrates was measured by means of a field emission scanning microscope (FESM). It turned out that in situ heat treatment (HT) of the Mo surface significantly changes the FE behaviour by activation of new emitters. For a better understanding of the mechanism for enhanced emission after in situ heating a witness Mo sample was investigated using x-ray photoelectron spectroscopy.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO042

Export •

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

THPRO043

Studies on the Application of the 3D Ellipsoidal Cathode Laser Pulses at PITZ

laser, booster, emittance, flattop

2958

M. Khojoyan, M. Krasilnikov, F. Stephan
DESY Zeuthen, Zeuthen, Germany

Funding: The work is funded by the German federal Ministry of education and Research, project 05K10CHE “development and experimental test of a laser system for producing quasi 3D ellipsoidal laser pulses”.
The Photo Injector Test facility at DESY, Zeuthen Site (PITZ) characterizes and optimizes high brightness electron sources for FLASH and the European XFEL. At nominal conditions the electron bunches are created from a photocathode laser with flat-top temporal distribution and sharp rise and fall times. Beam dynamics simulations using a 3D ellipsoidal cathode laser shape yielded to a significant improvement of the electron beam quality compared to the traditionally used cylindrically shaped beams. The 3D ellipsoidal laser system is under development at the Institute of Applied Physics (IAP) and will be used at PITZ soon, to create high quality electron beams. The recent studies of electron beam simulations at PITZ have been devoted to the position optimization of the second accelerating cavity for the 3D ellipsoidal laser profile. Electron beam properties were compared for cylindrical and 3D ellipsoidal beams applying default and optimized booster positions. Beam tolerance studies revealed much better injector performance for the 3D ellipsoidal laser profile case with the optimized booster position. The outcome of such investigations is presented and discussed in this contribution.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO043

Export •

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

THPRO045

Design and Construction of a Thermionic Cathode RF Electron Gun for Iranian Light Source Facility

gun, linac, simulation, emittance

2965

A. Sadeghipanah, H. Ghasem, J. Rahighi, Kh.S. Sarhadi
ILSF, Tehran, Iran

We present a program for the design and construction of a thermionic cathode RF gun to produce bright electron beams, consisting in the first step toward the possible development of S band linac based pre-injector at Iranian Light Source Facility (ILSF). The program is aimed at the goal to attain a beam quality as requested by ILSF. As a first step within this mainstream, we are currently developing a thermionic cathode side coupling RF electron gun which is expected to deliver 100 pC bunches with emittances below 2 mm-mrad at 2.5 MeV. We report the performed simulation and design activity, as well as cold test results of first fabricated prototype, which are in good agreement with simulation results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO045

Export •

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

THPRO047

Linac Design for the Proposed NSRRC THz/VUV FEL Facility

linac, bunching, optics, emittance

2971

N.Y. Huang, W.K. Lau, A.P. Lee
NSRRC, Hsinchu, Taiwan
A. Chao, J. Wu
SLAC, Menlo Park, California, USA
C.H. Chen
NTHU, Hsinchu, Taiwan

A driver linac based on a photocathode RF gun injector system for a proposed free electron laser facility at National Synchrotron Radiation Research Center (NSRRC) in Taiwan is under study. This facility is designed to be operated in two modes, one for the VUV application and one for the THz application to fulfil the user needs. Generally the VUV radiation prefers a low emittance, high peak current beam free from collective instability during acceleration and magnetic pulse compression, whereas the THz radiation needs a moderate charge in hundred femtosecond bunch length free from space charge degradation in a transport line. In this paper, the schemes of bunch compression as well as the strategy to optimize and control of the beam quality will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO047

Export •

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

THPRO048

Emittance and Bunch Length Measurement of the Electron Beams from the NSRRC Photocathode Gun

emittance, gun, cavity, space-charge

2974

A.P. Lee, M.C. Chou, N.Y. Huang, J.-Y. Hwang, W.K. Lau, C.C. Liang
NSRRC, Hsinchu, Taiwan
P. Chiu, P. Wang
NTHU, Hsinchu, Taiwan
Y. Hao
BNL, Upton, Long Island, New York, USA

A high brightness photo-injector is under development for single pass FEL research at NSRRC. The gun test facility (GTF) equipped with a photocathode rf gun a compensation solenoid, a S-band high power pulse klystron as well as a UV driver laser has been constructed for testing the photocathode rf gun. The gun is fabricated in house and being tested at the GTF. Since the transverse emittance is a key property of the electron beam from the rf gun, multi-slit method is used to characterize the transverse emittance of the electron beam. Another key property of the electron beam is bunch length. An S-band three-cell deflecting cavity is designed to measure the bunch length. The setup and results of emittance measurement as well as the structure design of the deflecting cavity is reported in this contribution.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO048

Export •

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

THPRO049

Magnet AC Analysis of a Taiwan Light Source Booster

quadrupole, booster, network, factory

2977

H.C. Chen, H.H. Chen, S. Fann, S.J. Huang, A.P. Lee, J.A. Li, C.C. Liang, Y.K. Lin
NSRRC, Hsinchu, Taiwan

The Response Surface Methodology (RSM), is used to study the optimization process of magnet AC in the booster for Taiwan Light Source (TLS) in National Synchrotron Radiation Research Center (NSRRC). A study model was constructed based on the Artificial Neural Network (ANN) theory. The theoretical model and optimization procedure were both implemented to evaluate the model. The details of the study will be reported in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO049

Export •

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

THPRO053

Ion Effects in the Cornell ERL High Intensity Photoinjector

ion, resonance, radiation, simulation

2989

S.J. Full, A.C. Bartnik, I.V. Bazarov, J. Dobbins, B.M. Dunham, G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

We present our first measurements of trapped ions in the Cornell energy recovery linac (ERL) photoinjector. During high intensity operation, ions become trapped inside of the electric potential generated by the electron beam and oscillate transversely with a characteristic frequency. At high beam currents, electron beam-ion interactions result in excessive radiation, primarily due to beam losses and bremsstrahlung. However, by shaking the beam at the trapped ion's oscillation frequency, we are able to drive a resonance that severely reduces or eliminates this radiation. This both confirms the viability of beam shaking as an ion mitigation strategy inside high intensity injectors, and allows us to measure the trapped ion oscillation frequencies indirectly. Experimental data for a beam energy of 5 MeV, a bunch repetition rate of 1.3 GHz, and beam currents up to 20 mA, as well as simulations to describe our data and the beam shaking principle are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO053

Export •

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

THPRO055

Electron Beam Final Focus System for Thomson Scattering at ELBE

quadrupole, permanent-magnet, focusing, laser

2995

J.M. Krämer, F. Bødker, A. Baurichter, M. Budde
Danfysik A/S, Taastrup, Denmark
A. Irman, U. Schramm
Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany
U. Lehnert, P. Michel
HZDR, Dresden, Germany

Funding: This work is part of LA3NET and funded by European Commission under Grant Agreement Number 289191.
The design of an electron beam Final Focus System (FFS) aiming for high-flux laser-Thomson backscattering x-ray sources at ELBE* is presented. A telescope system consisting of four permanent magnet based quadrupoles was found to have significantly less chromatic aberrations than a quadrupole triplet. This allows sub-ps electron beam focusing to match the laser spot size at the interaction point. Focusing properties like the position of the focal plane and the spot size are retained for electron beam energies between 20 and 30 MeV by adjusting the position of the quadrupoles individually on a motorized stage. Since the electron beam is chirped for bunch compression upstream, the rms energy spread is increased to one or two percent and second order chromatic effects must be taken into account. For an emittance of 13 pi mm mrad, we predict rms spot sizes of about 40 um and divergences of about 15 mrad. We also present the design of the permanent magnet quadrupoles to be used for the FFS. Ferromagnetic poles ensure a high field quality and adjustable shunts allow for fine adjustment of the field strength and compensation of deviations in the permanent magnet material.
*A. Jochmann et al., Phys. Rev. Lett. 111 (2013) 114803

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO055

Export •

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

THPRO060

Beam-beam Effect on the BTF in Bunched Beams

simulation, damping, beam-beam-effects, operation

3011

P.A. Görgen, O. Boine-Frankenheim
TEMF, TU Darmstadt, Darmstadt, Germany
W. Fischer
BNL, Upton, Long Island, New York, USA

We present studies on the transverse baseband Beam Transfer Functions (BTFs) in bunched beams at high energies. The goal of the work is to evaluate whether transverse BTFs can be used to diagnose the tune spread arising from transverse nonlinearities such as the beam-beam effect and space charge. We employ an analytic expression to the BTFs of beams under a transverse nonlinear lens arising from a bi-Gaussian charge distribution. We obtain agreement between a simulation model of an electron-lens like configuration and the analytic results. The tune spread for this scenario can be recovered by means of a fit against the analytic expectation. The results are compared with measurements where the beam-beam effect acts as a substitute for the electron lens. A similar behaviour of the BTF is observed. This allows the conclusion that the transverse BTF can be used to diagnose tune spread from an electron-lens. Finally we discuss the problems that arise when trying to recover the tune spread from BTFs of arbitrary non-Gaussian beams and in the presence of coherent beam-beam modes.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO060

Export •

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

THPRO064

Effect of Laser-plasma Channeling on Third-harmonic Radiation Generation

laser, plasma, radiation, focusing

3023

M. Singh, D.N. Gupta
University of Delhi, Delhi, India

An intense Gaussian laser beam, propagating through a magnetized plasma, becomes self-focused due to the ponderomotive force on the electrons. The magnetic field reduces the radius of the laser beam and enhances the self focusing of the laser beam. The self-sustained plasma channel can affect the efficiency of harmonic generation of the interacting laser beam. The radial density gradient of the channel beats with the oscillatory electron velocity to produce density perturbation at laser frequency. The ponderomotive force at second-harmonic frequency produces electrons density oscillations that beat with the oscillatory velocity to create a non-linear current, driving the third harmonic radiation. The velocity and density perturbation associated with the self-focused laser beam generates a nonlinear current at triple fold frequency of the fundamental laser. Our results show that the efficiency of third-harmonic generation of the laser beam is affected significantly due to the self-sustained plasma channel. The strength of magnetic field play a crucial role in efficiency enhancement of third-harmonic generation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO064

Export •

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

THPRO066

Correction of the Higher Order Dispersion for Improving Momentum Acceptance

optics, storage-ring, emittance, betatron

3029

M. Takao, K.K. Kaneki, Y. Shimosaki, K. Soutome
JASRI/SPring-8, Hyogo-ken, Japan

May 2013 we lowered the emittance of the SPring-8 storage ring from 3.5 nm¥cdotrad to 2.4 nm¥cdotrad to enhance the brilliance. At the optics change the momentum acceptance shrunk from 3.2 ¥% to 2.4 ¥%. Then, by carefully correcting the second order dispersion, we recovered the momentum acceptance up to 2.8 ¥%, which results in doubling the Touschek beam lifetime. Although the injection efficiency decreased by more than 10 ¥% by the dispersion correction, we restored it by means of suppressing the amplitude dependent tune shift. Here we describe these improvements of the nonlinear dynamics of the SPring-8 storage ring.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO066

Export •

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

THPRO096

Nonlinear Oscillations of a Sheet Electron Beam

emittance, plasma, simulation, brightness

3113

H.Y. Barminova
MEPhI, Moscow, Russia

In collisionless approximation the nonlinear dynamics of continuous strong current intense electron beam is investigated. Nonlinear oscillations of the beam radius appear due to self-consistent nonlinear forces. To study these oscillations the model is used that automatically satisfy to Vlasov equation. The oscillations are described by means of Duffing equation. The equilibrium state is shown to exist. The solutions near the equilibrium state are analyzed. The asymptotic character of the solutions is found. Nonlinear beam transverse oscillations lead to filamentation and effective emittance growth. If particle energy dissipation is absent in the beam transportation channel the physical reason of the effective emittance growth is transfer of the part of the beam potential energy to kinetic energy of the particle transverse oscillations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO096

Export •

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

THPME079

Beam Diagnostics and Control for the AREAL RF Photogun Linac

controls, diagnostics, linac, gun

3418

G.A. Amatuni, B. Grigoryan, A. Lorsabyan, N. Martirosyan, V. Sahakyan, A. Sargsyan, A.V. Tsakanian, A. Vardanyan, G.S. Zanyan
CANDLE SRI, Yerevan, Armenia
K. Manukyan
YSU, Yerevan, Armenia

Advanced Research Electron Accelerator Laboratory (AREAL) based on photo cathode RF gun is under construction at CANDLE. In current stage the gun section is under commissioning (phase 1). This paper presents the main characteristics of gun section beam diagnostics and the architecture of AREAL control system. The diagnostic system includes the measurements of the beam main parameters and its longitudinal and transverse phase space characteristics. The results of the facility first phase commissioning are summarized from the beam diagnostic and control point of view.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME079

Export •

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

THPME088

Study of Phase Reconstruction Techniques applied to Smith-Purcell Radiation Measurements

radiation, simulation, diagnostics, monitoring

3436

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

Funding: Work supported by the France-Ukraine high energy physics laboratory and by the Université Paris-Sud (programme “attractivité") and the French ANR (contract ANR-12-JS05-0003-01).
Measurements of coherent radiation at accelerators typically give the absolute value of the beam profile Fourier transform but not its phase. Phase reconstruction techniques such as Hilbert transform or Kramers Kronig reconstruction are used to recover such phase. We report a study of the performances of these methods and how to optimize the reconstructed profiles.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME088

Export •

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

THPME092

Status of Diamond Detector Development for Beam Halo Investigation at ATF2

detector, vacuum, photon, cathode

3449

S. Liu, P. Bambade, F. Bogard, J-N. Cayla, H. Monard, C. Sylvia, T. Vinatier
LAL, Orsay, France
N. Fuster-Martínez
IFIC, Valencia, Spain
I. Khvastunov
National Taras Shevchenko University of Kyiv, The Faculty of Physics, Kyiv, Ukraine
T. Tauchi, N. Terunuma
KEK, Ibaraki, Japan

Funding: Chinese Scholarship Council
We are developing a diamond detector for beam halo and Compton spectrum diagnostics after the interaction point (IP) of ATF2, a low energy (1.3 GeV) prototype of the final focus system for ILC and CLIC linear collider projects. Tests of a 500 μm thick sCVD diamond detector with a dimension of 4.5 mm×4.5 mm have been carried out with radioactive sources and with electron beam from PHIL low energy (<10 MeV) photo-injector at LAL. The tests at PHIL were done with different beam intensities in air, just after the exit window at the end of the beam line, to test the response of the diamond detector and the readout electronics. We have successfully detected signals from single electrons, using a 40 dB amplifier, and from an electron beam of 10⁸ electrons, using a 24 dB attenuator. A diamond sensor with 4 strips has been designed and fabricated for installation in the vacuum chambers of ATF2 and PHIL, with the aim to scan both the beam halo (with 2 strips of 1.5 mm×4 mm) and the beam core (with 2 strips of 0.1 mm×4 mm) transverse distributions.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME092

Export •

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

THPME093

Reconstruction of Longitudinal Electrons Bunch Profiles at FACET, SLAC

radiation, background, detector, wakefield

3453

M. Vieille Grosjean, J. Barros, N. Delerue, S. Jenzer
LAL, Orsay, France
F. Bakkali Taheri, G. Doucas, I.V. Konoplev, A. Reichold
JAI, Oxford, United Kingdom
C.I. Clarke
SLAC, Menlo Park, California, USA

The E-203 collaboration is testing a device on FACET at SLAC to measure the longitudinal profile of electron bunches using Smith-Purcell radiation. At FACET the electron bunches have an energy of 20GeV and a duration of a few hundred femtoseconds. Smith-Purcell radiation is emitted when a charged particle passes close to the surface of a metallic grating. The set-up installed in FACET consists in four targets (three gratings and a blank) on a carrousel on one side and eleven pyroelectric detectors on the opposite side, the beam passing between. At the moment, the measurement is averaged over a hundred pulses or more. We have studied the stability of the measurement from pulse to pulse and the resolution of the measure depending on the number of grating used.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME093

Export •

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

THPME094

Measurement of Low-charged Electron Beam with a scintillator Screen

detector, diagnostics, laser, vacuum

3456

T. Vinatier, P. Bambade, C. Bruni, S. Liu
LAL, Orsay, France

Measuring electron beam charge lower than 1pC is very challenging since the traditional diagnostics, like Faraday Cup and ICT, are limited in resolution to a few pC. A way to simply measure lower charge would be to use the linear relation, existing before saturation regime, between the incident charge and the total light intensity emitted by a YAG screen. Measurement has been performed on PHIL accelerator at LAL, with charge lower than 50pC, with a YAG screen located just in front of a Faraday Cup. It shows a very good linear response of the YAG screen up to the Faraday Cup resolution limit (2pC) and therefore allows calibrating the YAG screen for lower charge measurement with an estimated precision of 4%. A noise analysis allows estimating the YAG screen resolution limit around 40fC. Results of low charge measurement on PHIL will be shown and compared to those coming from a diamond detector installed on PHIL, in order to validate the measurement principle and to determine its precision and resolution limit. Such simple measurement may thereafter be used as single-shot charge diagnostic for electron beam generated and accelerated by laser-plasma interaction.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME094

Export •

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

THPME095

Length Measurement of High-brightness Electron Beam thanks to the 3-Phase Method

gun, booster, laser, flattop

3459

T. Vinatier, C. Bruni, S. Chancé, P.M. Puzo
LAL, Orsay, France

The goal of 3-phase method is to determine the length of an electron beam without dedicated diagnostics by varying the measurement conditions of its energy spread, through a change in the RF phase of an accelerating structure. The originality here comes from the fact that it is applied on high-brightness electron beams of few MeV generated by RF photo-injectors. It allows testing the accuracy of 3-phase method, since the length to reconstruct is known as being that of the laser pulse generating the beam. It requires establishing the longitudinal transfer matrix of a RF photo-injector, which is difficult since the electron velocity vary from 0 to relativistic during its path*. The 3-phase method in RF photo-injector has been simulated by ASTRA and PARMELA codes, validating the principle of the method. First measurement has been done on PHIL accelerator at LAL, showing a good agreement with the expected length. I will then show results obtained at PITZ with a standing wave booster and a comparison with those coming from a Cerenkov detector. Finally, measurements at higher energy performed on the SOLEIL LINAC with travelling wave accelerating structures will be exposed.
* : K-J. Kim, “RF and Space Charge Effects in Laser-Driven RF Electron Guns”, Nucl. Instr. Meth., A275, 201 (1989)

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME095

Export •

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

THPME097

Schottky Diode Detectors for Monitoring Coherent THz Synchrotron Radiation Pulses

detector, radiation, synchrotron, synchrotron-radiation

3465

A. Semenov, H.-W. Hübers, A. Pohl
DLR, Berlin, Germany
O. Cojocari, M. Sobornytskyy
ACST GmbH, Hanau, Germany
A. Hoehl, R. Müller
PTB, Berlin, Germany
M. Ries, G. Wüstefeld
HZB, Berlin, Germany

Coherent synchrotron radiation (CSR) in the terahertz frequency range is a powerful tool for the diagnostics of the electron-beam relying on the fact that the emission spectrum of THz CSR depends on the shape of the electron bunch from which the radiation is emitted. Among available direct THz detectors only superconducting microbolometers and Schottky diodes are capable to resolve single CSR pulses. Here we present recent photoresponse measurements of CSR with a quasioptical zero-bias Schottky diode detector which was produced at ACST GmbH. The rise-time of the recorded real-time transient was limited to approximately 20 ps by the 18-GHz bandwidth of interconnecting cables. Non-saturated responsivity of the detector, that is the amplitude of the voltage transient referred to the total CSR pulse energy in the detector quasioptical mode, was approximately 1.5 mV/fJ. The dynamic range of the detector spans almost three orders of magnitude from 3 fJ to 1 pJ. The intrinsic jitter of the detector was less than 2 ps thus not affecting the effective time resolution and allowing us to measure the arrival-time jitter of CSR pulses for different settings of the storage ring parameters.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME097

Export •

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

THPME106

Compact Integrated THz Spectrometer in GaAs Technology for Electron Bunch Compression Monitor Applications

detector, radiation, synchrotron, diagnostics

3489

N. Neumann, M. Laabs, D. Plettemeier, M. Schiselski
TU Dresden, Dresden, Germany
M. Gensch, B.W. Green, S. Kovalev
HZDR, Dresden, Germany

Funding: BMBF 05K13ODB
Bunch compression monitors are essential for the efficient operation of linear accelerators. The spectral distribution of coherently generated THz radiation is a favorable measure for the shape of the electron bunches. Today, THz spectrometers are bulky and costly. Here, the concept of an integrated on-chip semiconductor spectrometer being developed in a joint effort by HZDR and TU Dresden within the scope of the BMBF project InSEl is presented. This potentially low-cost and compact solution based on Schottky diode detectors, integrated on-chip THz antennas and filters fabricated in a commercial GaAs process will not exceed 5 mm in size replacing current single element THz detectors in the bunch compression monitors in the ELBE accelerator at HZDR. Covering the frequency range from 0.1 to 1.5 THz (and more in the future) with a resolution of 5 to 20 points, it could also be of interest for the longitudinal electron bunch diagnostic at other electron linacs such as FLUTE, BERLinPro, FLASH or the European X-FEL. Furthermore, the detector bandwidth in the GHz range supports the high repetition rates of superconducting radio frequency accelerators.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME106

Export •

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

THPME109

EOS at CW Beam Operation at ELBE

laser, operation, FEL, diagnostics

3492

Ch. Schneider, M. Gensch, M. Kuntzsch, P. Michel, W. Seidel
HZDR, Dresden, Germany
P.E. Evtushenko
JLab, Newport News, Virginia, USA
Ç. Kaya
Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
A. Shemmary, N. Stojanovic
DESY, Hamburg, Germany

The ELBE accelerator is a super conduction electron cw machine located at the Helmholtz Center Dresden Rossendorf Germany with 1 mA current, now tested for up to 2 mA. Besides other important diagnostics for setting up the machine for user beam time and further improvement of the machine – a THz source is momentary under commissioning – a EOS measuring station for bunch length measurements is locate right behind the second super conducting Linac. Measuring with a crystal in the vicinity of an up to 2 mA cw beam implies higher beam loss and also higher radiation exposure of the crystal and hence also a safety risk for the UHV conditions of the super conducting cavities in the case of crystal damage. Therefore the EOS measuring principle is adapted to larger measuring distances and also for beam requirements with lower bunch charge at ELBE. A description of the setup, considerations of special boundary conditions and as well results for 13 MHz cw beam operation are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME109

Export •

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

THPME112

Design of a Compact Setup to Measure Beam Energy by Detection of Compton Backscattered Photons at ANKA

photon, laser, background, detector

3494

C. Chang, D. Batchelor, E. Hertle, E. Huttel, V. Judin, A.-S. Müller, A.-S. Müller, A.-S. Müller, M.J. Nasse, M. Schuh, J.L. Steinmann
KIT, Eggenstein-Leopoldshafen, Germany

Funding: This work is funded by the European Union under contract PITN-GA-2011-289191
One of the most important parameters of accelerators is their beam energy. So far, the method of resonant depolarization was used to accurately determine the energy at 2.5 GeV of the ANKA electron storage ring, which, however, becomes cumbersome for lower energies. A good alternative is the detection of Compton backscattered photons, generated by laser light scattered off the relativistic electron beam. To achieve compactness and integration into the storage ring, the setup of transverse scattering is proposed instead of conventional head-on collision. The feasibility has been studied by comparison between simulations of Compton backscattered photons by AT and CAIN 2.35 and actual measurement of background radiation with an HPGe (High Purity Germanium) spectrometer. The layout of the setup is also included in the paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME112

Export •

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

THPME114

Commissioning and First Beam Measurements with a New Beam Diagnostics for Medical Electron Accelerators

diagnostics, simulation, injection, quadrupole

3500

D. Vlad
Siemens AG Healthcare, H CP CV - Components and Vacuum, Erlangen, Germany
G. Fischer
Friedrich-Alexander Universität Erlangen-Nuernberg, University Erlangen-Nuernberg LFTE, Erlangen, Germany
M. Hänel
Siemens Healthcare, Erlangen, Germany

A new beam diagnostics system was developed and built at the Siemens Healthcare Sector facility in Rudolstadt, Germany. The project goal was to develop, commission and operate a complete beam diagnostics system to fully characterize the compact medical linear electron accelerators. An overview of the whole system including the beam diagnostics, linear accelerator and control and supply unit is given. The system was successfully commissioned in July 2013. We report on initial experiences and first experimental results on current measurements, transverse beam size, transverse emittance and momentum and momentum distribution gained during the commissioning phase.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME114

Export •

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

THPME115

EUV Radiation Generated by a 5.7 MeV Electron Beam in Multilayer Periodical Structure

radiation, target, experiment, photon

3503

S.R. Uglov, A. Potylitsyn, L.G. Sukhikh, A.V. Vukolov
TPU, Tomsk, Russia
G. Kube
DESY, Hamburg, Germany

Funding: This work was partly supported by the by the Ministry of Education Science of the Russian Federation, contract 2.1799.2011.
Recent experience from linac based FELs like LCLS or FLASH shows that transverse beam imaging based on optical transition radiation (OTR) might fail due to coherence effects in the OTR emission process. In order to overcome the problem it was proposed to use transition radiation (TR) in the EUV region*. For a reliable beam diagnostics however, an increase of the light output in the EUV region is required. One possibility to increase the radiation yield in the geometry of interest (target tilt angles 22.5 or 45 degrees) is to exchange the conventional monolayer target by a multilayer structure which acts as a multilayer X-ray mirror for EUV radiation. In this case, two radiation components are expected to contribute to the measured signal, diffracted transition radiation (DTR) and parametric radiation (PR)**. In this report we present results of an experimental investigation of EUV TR generated by a 5.7 MeV electron beam at monolayer and multilayer targets. The angular characteristics of the radiation was investigated and compared with theoretical models.
* L.G. Sukhikh, S. Bajt, G. Kube et al., in Proc. IPAC'12, MOPPR019, New Orleans, Louisiana, USA, p.819 (2012)
** N.Nasonov, V.Kaplin, S.Uglov, e al., Phys. Rev. E 68 (2003) 036504

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME115

Export •

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

THPME118

A Freon-filled Bubble Chamber for Gamma-ray Detection in Strong Laser-plasma Interaction

photon, laser, plasma, detector

3512

W.B. Zhao, J.E. Chen, C. Lin, L.H.Y. Lu, X.Q. Yan, Y.Y. Zhao, B.Y. Zou
PKU, Beijing, People's Republic of China

When a laser pulse with focused intensity exceeding 1018W/cm² interacts with a solid target, electrons in the focal spot are accelerated to relativistic velocity and where they generate inner-shell vacancies and hard x-ray(>10 keV) spectral line and Bremsstrahlung radiation. In laser plasma interactions, the resonance between betatron motion of electrons and ultraintense laser pulses is an interesting phenomenon in both electron acceleration and gamma photon production. Even though the gamma-ray synchrotron is micron scale, the energy ranges from ~1 MeV to ~102MeV. To detect the energy of the gamma-ray accurately is particularly significant. Owing to a lot of various energy of gamma-ray are emitted in femtosecond scale, which are impossible distinguished from each other on the time. A small freon-filled bubble chamber is being built to measure the energy spectrum of high-energy photons. After that, we can calculate the electron’s energy and then offer the data for various of electron acceleration theories. It combines a good spatial resolution with a large depth of field, allowing a large number of tracks. This improves the statistical quality of the photon spectrum.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME118

Export •

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

THPME119

Transverse emittance measurement at REGAE

emittance, target, diagnostics, simulation

3515

S. Bayesteh
Uni HH, Hamburg, Germany
H. Delsim-Hashemi, K. Flöttmann
DESY, Hamburg, Germany

A new linac, named REGAE (Relativistic Electron Gun for Atomic Exploration) has been built at DESY and operates as an electron source for ultra-fast electron diffraction. An RF photocathode gun provides electron bunches of high coherence, sub-pC charge and energies of 2-5 MeV. In order to film time-resolved structural changes of excited specimens, bunch lengths of several femtoseconds need to be created. Taking into account these critical parameters, beam diagnostics at REGAE is very challenging. The existing diagnostics consists of energy, energy spread, beam profile, beam charge and emittance measurements. For transversal diagnostics, specific approaches have to be considered to overcome complications associated with the low charge and to carry out the beam diagnostics in single shot. In this paper, the contribution of the transversal diagnostics to the measurement of the transverse emittance is presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME119

Export •

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

THPME123

Electro-optical Bunch Length Monitor for FLUTE: Layout and Simulations

laser, simulation, linac, gun

3527

A. Borysenko, E. Hertle, N. Hiller, V. Judin, B. Kehrer, S. Marsching, A.-S. Müller, M.J. Nasse, R. Rossmanith, R. Ruprecht, M. Schuh, M. Schwarz, P. Wesolowski
KIT, Karlsruhe, Germany
B. Steffen
DESY, Hamburg, Germany

Funding: This work is funded by the European Union under contract PITN-GA-2011-289191
A new compact linear accelerator FLUTE is currently under construction at Karlsruhe Institute of Technology (KIT) in collaboration with DESY and PSI. It aims at obtaining femtosecond electron bunches (~1fs - 300 fs) with a wide charge range (1 pC - 3 nC) and requires a precise bunch length diagnostic system. Here we present the layout of a bunch length monitor based on the electro-optic technique of spectral decoding using an Yb-doped fiber laser system (central wavelength 1030 nm) and a GaP crystal. Simulations of the electro-optic signal for different operation modes of FLUTE were performed and main challenges are discussed in this talk. This work is funded by the European Union under contract PITN-GA-2011-289191

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME123

Export •

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

THPME125

Electrical Field Sensitive High-Tc YBCO Detector for Real-time Observation of CSR

detector, real-time, synchrotron, operation

3533

J. Raasch, K.S. Ilin, Y.-L. Mathis, A.-S. Müller, A. Scheuring, M. Siegel, N.J. Smale, P. Thoma
KIT, Karlsruhe, Germany
S. Bielawski, C. Evain, E. Roussel, C. Szwaj
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
B. Holzapfel
Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
M. Hosaka, N. Yamamoto
Nagoya University, Nagoya, Japan
K. Iida
Leibniz Institute for Solid State and Materials Research Dresden, Dresden, Germany
M. Katoh, S.I. Kimura, T. Konomi
UVSOR, Okazaki, Japan
H. Zen
Kyoto University, Kyoto, Japan

Funding: We thank Agilent Technologies & Tektronix for supplying oscilloscopes. The work was supported by BMBF (05K2010), ANR (2010 blanc 042301), MEXT (Quantum Beam Tech. Prog.), IMS (Int. Collab. Prog.).
High-Tc thin-film YBa2Cu3O7-x (YBCO) detectors were deployed for the real-time observation of Coherent Synchrotron Radiation (CSR). Due to enhanced fabrication techniques enabling the patterning of sub-μm sized detector areas responsivity values as high as 1V/pJ for pulsed THz excitations have been achieved at the ANKA synchrotron facility at the Karlsruhe Institute of Technology (KIT). Response of the detectors is linear over the whole dynamic range of the IR1 beamline. Combining the picosecond scaled response mechanism of the high-temperature superconductor YBa2Cu3O7-x (YBCO) to THz excitations with broad-band readout a temporal resolution of 15 ps full width at half maximum (FWHM) was reached. Real-time resolution of CSR single shots was observed at ANKA and UVSOR-III, the synchrotron facility of the Institute of Molecular Science in Okazaki, Japan.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME125

Export •

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

THPME128

Fast Beam Diagnostics for Third-Generation Synchrotrons by Means of Novel Diamond-based Photon BPMs

photon, diagnostics, detector, radiation

3541

M. Antonelli, G. Cautero, I. Cudin, D.M. Eichert, D. Giuressi, W.H. Jark, E. Karantzoulis, S. Lizzit, R.H. Menk
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
A. De Sio, E. Pace
Università degli Studi di Firenze, Firenze, Italy
M. Di Fraia
Università degli Studi di Trieste, Trieste, Italy

In the past years electron beam stability has been intensively addressed In new-generation Synchrotron Radiation (SR) sources. Many SR machines have been equipped with a Fast Orbit Feedback (FOFB) based on electron Beam-Position Monitors (eBPMs). Also photon Beam-Position Monitors (pBPMs) are a useful tool for keeping the electron beam under control by simultaneously monitoring position and intensity of the delivered radiation; the machine control system can take advantage of this information in order to improving the electron beam stability. At Elettra, a diagnostic beamline, which utilizes a couple of single-crystal CVD diamond detectors as fast pBPMs, has been built and inserted into a bending-magnet front end. Preliminary tests carried out during normal machine operations show that this system allows to monitor the beam position with sub-micrometric precision at the demanding readout rates required by the FOFB. Therefore, this diagnostic line represents a demonstrator for future implementation of pBPMs at several bending-magnet front ends of Elettra.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME128

Export •

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

THPME132

Generation and Diagnosis of Ultrashort Electron Bunches from a Photocathode RF Gun Linac

detector, linac, gun, laser

3553

I. Nozawa, M. Gohdo, K. Kan, T. Kondoh, K. Norizawa, A. Ogata, J. Yang, Y. Yoshida
ISIR, Osaka, Japan
H. Kobayashi
KEK, Ibaraki, Japan

Ultrashort electron bunches are essential for time-resolved measurement methods such as pulse radiolysis* from the viewpoint of time resolutions. On the other hand, generation of electro-magnetic wave in the THz range using short electron bunches has been investigated**. Frequency spectra of coherent transition radiation (CTR) emitted by an electron bunch depend on bunch form factor (BFF), which is expressed by Fourier coefficients of longitudinal distribution in the electron bunch. In this study, the bunch length measurement was demonstrated by analyzing THz-waves generated by CTR. Femtosecond electron bunches were generated by a laser photocathode RF gun linac and magnetic bunch compressor. THz-waves generated by CTR, which was emitted on an interface of an aluminum mirror along the beam trajectory, were transported to a Michelson interferometer. The bunch length was measured by analyzing interferogram, which was an infrared detector output as a function of a moving mirror position. Finally, the bunch length was measured according to fitting curves for the interferogram near the centerburst***. Minimum bunch length of 1.3 fs was obtained at a bunch charge of ~1 pC.
*J. Yang et al., Nucl. Instrum. Meth. A 556, 52 (2006).
**K. Kan et al., Appl. Phys. Lett. 99, 231503 (2011).
***A. Murokh et al., Nucl. Instrum. Meth. A 410 (1998).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME132

Export •

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

THPME133

Bunch Length Measurement with 2-Cell RF-Deflector at Waseda University

cavity, gun, cathode, coupling

3556

T. Takahashi, Y. Nishimura, M. Nishiyama, K. Sakaue, M. Washio
Waseda University, Tokyo, Japan
T. Takatomi, J. Urakawa
KEK, Ibaraki, Japan

We have been studying on a system to measure the length of electron bunch generated by a photocathode rf electron gun at Waseda University. We adopted the rf-deflector system which can convert the longitudinal distribution to transverse by sweeping the electron bunch. By using HFSS, we optimized the design of the 2 cell rf-deflector which is operating on π-mode, dipole (TM110-like) mode at 2856 MHz. The fabrication and the tuning of the rf deflector have successfully processed. We have installed the rf-deflector in the accelerator system of Waseda University, and performed the measurement of the bunch length. It is confirmed that this rf-deflector has the temporal resolution of 167fs with 700kW supply when the beam energy is 4.8MeV. This means that our rf-deflector system has possibility to measure the ultra-short bunch length. In this conference, the rf-deflector system in Waseda University, the result of the bunch length measurement, the performance of the rf-deflector and the future plan will be reported.
Work supported by JSPS Grant-in-Aid for Scientific Research (A) 10001690 and the Quantum Beam Technology Program of MEXT.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME133

Export •

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

THPME134

Experimental Results of a Gas Jet Based Beam Profile Monitor

vacuum, ion, alignment, storage-ring

3559

V. Tzoganis
RIKEN Nishina Center, Wako, Japan
A. Jeff, V. Tzoganis, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
A. Jeff, V. Tzoganis, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A. Jeff
CERN, Geneva, Switzerland

Funding: Work supported by the EU under grant agreement 215080, HGF and GSI under contract number VH-NG-328, the STFC Cockcroft Institute Core Grant Mo.ST/G008248/1, and a RIKEN-Liverpool studentship.
A novel, least invasive beam profile monitor based on a supersonic gas jet has been developed by the QUASAR Group at the Cockcroft Institute, UK. It allows the measurement of beam profiles for various particle beams across a range of energies and vacuum levels to be made. A finely collimated neutral gas jet, produced by a nozzle and several skimmers, is injected into a vacuum chamber perpendicular to the main particle beam. Ionization by the primary beam produces ions which are extracted from the interaction region and directed towards an imaging detector. This contribution presents the design of the monitor and first experimental results obtained with a low energy electron beam. It also discusses solutions of previous alignment problems and challenges in the realization of a versatile control and data acquisition system

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME134

Export •

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

THPME135

Simulations of the Ion Spatial Distribution in a Gas-Curtain Based Beam Profile Monitor

ion, extraction, simulation, antiproton

3563

B.B.D. Lomberg, A. Jeff, V. Tzoganis, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A. Jeff, B.B.D. Lomberg, V. Tzoganis, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
A. Jeff
CERN, Geneva, Switzerland
V. Tzoganis
RIKEN Nishina Center, Wako, Japan

Funding: Work supported by the EU under grant agreement 215080 and 289485, HGF and GSI under contract VH-HG-328, the STFC Cockcroft Institute Core Grant No. ST/G008248/1, and a RIKEN-Liverpool studentship.
A gas-jet monitor has been developed and commissioned by the QUASAR Group at the Cockcroft Institute, UK. It is designed to measure the transverse profile of a beam by crossing it with a neutral supersonic gas-jet. An array of high voltage electrodes is used to extract ions from the region where the beam and gas-jet interact. These ions first hit a micro-channel plate (MCP) and are then imaged through a phosphor screen and a CCD camera. It is important to understand and characterise the measured ion distribution in order to extract the beam profile. Therefore, numerical investigations using the commercial COMSOL and OPERA codes were carried out benchmarking profile measurements obtained from a low energy electron beam. This paper presents results from these studies. It compares measurements based on the interaction of the primary beam with the residual gas or the ultra-cold gas curtain, and discusses the comparisons of simulated profiles and extraction field configurations on the measured profile.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME135

Export •

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

THPME137

Preliminary Study of Non-invasive Beam Profile Measurements for Proton Beams

proton, gun, detector, ion

3569

H. He, J.S. Cao, Q.Y. Deng, J.H. Junhui, Y.F. Sui, J. Yue, Y. Zhao
IHEP, People's Republic of China
J. Chen
NSRRC, Hsinchu, Taiwan

Funding: This work was supported by NSFC under grant NO.11305186 and No.11205172
Two non-invasive beam profile measurement methods were developed for China high intensity proton beams projects, including CSNS and ADS. The first consists in an IPM (ionization beam profile monitor) system which detect the ionized products from a collision of the beam particle with residual gas atoms or molecules present in the vacuum pipe. The second is an electron beam scanner which using a low energy electron beam instead of a metal wire to sweep through the beam. The deflection of electron beam by the collective field of the high intensity beam is measured. The charge density in the high intensity beam can be restored under certain conditions or estimated by various mathematical techniques. Here we present the design parameters of the IPM system, the signal intensity of ionization products, optimization of the electric field, machine designs of electrode, tracking of the ionization products and so on. The principle of the electron beam scanner and the test results which is based on a commercial electron gun from Kimball Physics are also introduced in details.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME137

Export •

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

THPME140

New Beam Diagnostics and Related Study on HLS Photo-Injector and HLS II

cavity, quadrupole, diagnostics, emittance

3578

Q. Luo, H.T. Li, P. Lu, B.G. Sun, K. Tang, J.J. Zheng, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: Work supported by Natural Science Foundation of China 11005105, 11005106, 11205156 and 11375178.
A team in NSRL is now doing research about small model accelerators and carrying out series of related experiments on HLS photo-injector and HLS II storage ring. Cavity beam multi-parameter monitor system designed for the HLS photocathode RF electron gun consists of a beam position monitor, a beam quadrupole moment monitor and a beam density and bunch length monitor. TM0n0 modes of cavity can be used to work out beam density and bunch length simultaneously. Miniaturization of FEL facilities is now being studied based on results of experiments and theoretical work before. The team also participate in commissioning of HLS II, i.e. measured work points of the new storage ring and did some research on longitudinal bunch-by-bunch feedback system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME140

Export •

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

THPME141

Design of Beam Intensity Measurement System in Injector for HLS II

linac, controls, monitoring, instrumentation

3581

C. Cheng, P. Lu, B.G. Sun, K. Tang, J. Xu, Y.L. Yang, Z.R. Zhou, J.Y. Zou
USTC/NSRL, Hefei, Anhui, People's Republic of China

A new beam intensity measurement (BIM) system has been developed and has been used in the upgrade project of HLS II. After the upgrading is accomplished, electron energy in Injector endpoint will increase from 200MeV to 800MeV to achieve the goal of top-off injector. Meanwhile, macro pulse width changes from 1us to 1ns and peak intensity from 50mA to 1A approximately. So three fast current transformers (FCTs) and two integrating current transformer (ICTs) are installed in Linac and Transport Line to measure single pass beam parameters. In this article, off-line calibration of beam transformer is elaborated. Since the fast pulse signals from beam transformer will be hugely distorted after they transmit from Injector vacuum chamber to the Injector beam diagnostic centre room after hundreds of meters long LMR-400 cable, signal recovery algorithm based on FFT/IFFT is used to re-appear the true original signal and calculate the calibration efficient. In the end, resolution and measurement result of the BIM system is presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME141

Export •

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

THPME145

BPM Signal Channel Characterization Test based on TDR for HLS II Storage Ring

storage-ring, impedance, pick-up, simulation

3593

J.J. Zheng, C. Cheng, P. Lu, Q. Luo, B.G. Sun, Y.L. Yang, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

A new BPM system on the upgraded Hefei light source (HLSII) storage ring is installed. Before the machine commissioning, the BPM system should be carefully tested, such as the conductivity and integrity of BPM signal channels from button electrodes to digital beam position processors (pickups, cables and connectors). This paper presents an experience of signal channel test based on time domain reflection (TDR) for HLS II storage ring BPM system. Basing on the wave propagation method, an analytic expression for the signal from TDR on BPM signal channel is briefly introduced. The conductivity and integrity of the BPM signal channels can be verified by comparing the TDR waveform to theory signal. All the BPM signal channels are tested by the TDR in order to verify electronic characteristic and the usability. And some breakdowns are analysed and handled.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME145

Export •

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

THPME146

Bunch Length Measurement by Using a 2-Cell Superconducting RF Cavity in cERL Injector at KEK

cavity, experiment, gun, cathode

3596

J.G. Hwang, E.-S. Kim
Kyungpook National University, Daegu, Republic of Korea
T. Miyajima
KEK, Ibaraki, Japan

The development of future light source and linear colliders require high quality electron beams with short bunch length. The measurement of the bunch length is important technique for future electron machine. In general, the bunch length was measured by using deflecting cavity which has the time dependent transverse electromagnetic field. However, the transverse electric field of 2-cell superconducting RF (SRF) cavity can also provide the correlation between the bunch length and beam size as like the role of the deflecting cavity in bunch length measurement. The deflection strength was calibrated by changing the RF phase and the beam offset because the strength of transverse electric field of RF cavity depends on the phase of RF field and the beam offset in the cavity. We will present new way to measure the bunch length by using 2-cell SRF cavity, which has the acceleration field of 15 MV/m, and the measured result with the bunch length of 3 ps in cERL injector.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME146

Export •

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

THPME150

Spectrometer for SRF Gun

cavity, dipole, simulation, SRF

3608

I.Yu. Vladimirov, V.I. Shvedunov
MSU, Moscow, Russia
T. Kamps, J. Völker
HZB, Berlin, Germany

We report about the design of a spectrometer for energy spectrum measurements of an electron beam generated by a superconducting radio-frequency photoelectron gun (SRF gun), which is under construction at HZB for BERLinPro. The spectrometer shall provide absolute accuracy of energy measurements of about 0.1% and energy resolution about 0.1%. The spectrometer will be also used for single shot phase space measurements in combination with a transverse deflecting cavity.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME150

Export •

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

THPME151

New Station for Optical Observation of Electron Beam Parameters at Electron Storage Ring SIBERIA-2

storage-ring, diagnostics, vacuum, controls

3611

Stirin, A.I. Stirin, V. Korchuganov, G.A. Kovachev, D.G. Odintsov, Yu.F. Tarasov, A.V. Zabelin
NRC, Moscow, Russia
V.L. Dorohov, A.D. Khilchenko, A.L. Scheglov, L.M. Schegolev, A.N. Zhuravlev, E.I. Zinin
BINP SB RAS, Novosibirsk, Russia

The paper is dedicated to a new station for optical observation of electron beam parameters which was built at the synchrotron radiation (SR) storage ring SIBERIA-2 at Kurchatov Institute. The station serves for the automatic measurement of electron bunches transverse and longitudinal sizes with the use of SR visible spectrum in one-bunch and multi-bunch modes; the study of individual electron bunches behaviour in time with changing different accelerator parameters, the precise measurement of betatron and synchrotron oscillations frequency. The station with its diagnostic systems on the optical table is located outside the shielding wall of the storage ring. The paper contains an outline scheme of SR beam line and a block-scheme of optical measurement part, describes the principle of operation and technical characteristics of main system elements (dissector tube, 16-element avalanche photodiode array, CCD-matrix, etc.) as well as results of electron beam optical diagnostics and an estimation of accuracy of the bunches parameters measurements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME151

Export •

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

THPME153

The New Optical Device for Turn-to-turn Beam Profile Measurement

storage-ring, synchrotron, collider, positron

3617

O.I. Meshkov, V.L. Dorohov, A.A. Ivanova, A.D. Khilchenko, A.I. Kotelnikov, A.N. Kvashnin, P.V. Zubarev
BINP SB RAS, Novosibirsk, Russia
S.V. Ivanenko, E.A. Puryga
Budker Institute of Nuclear Physics, Novosibirsk, Russia
V. Korchuganov
RRC, Moscow, Russia
Stirin, A.I. Stirin
NRC, Moscow, Russia

The linear avalanche photodiodes array is applied for turn-to-turn beam profile measurement at Siberia-2 synchrotron light source. The apparatus is able to record a transversal profile of selected bunch and analyze the dynamics of beam during 2²⁰ turns. The first experience with application of new diagnostics for routine use at the installation is described.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME153

Export •

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

THPME155

Beam Phase Space Reconstruction for Monitoring the Luminosity in the VEPP-2000 Collider

luminosity, positron, lattice, collider

3623

A.L. Romanov, I. Koop, E. Perevedentsev, D.B. Shwartz
BINP SB RAS, Novosibirsk, Russia

16 synchrotron light imaging monitors available in VEPP-2000 can be used for evaluation of dynamic betas and emittances at collision. Tomographic techniques are useful for reconstruction of non-gaussian beam phase space at the IPs at high intensities of colliding bunches. The output is applied for prompt luminosity monitoring.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME155

Export •

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

THPME158

Coherent Diffraction and Cherenkov Radiation from Short Electron Bunches in Fibers

radiation, experiment, polarization, target

3632

G.A. Naumenko, V.V. Bleko, A. Potylitsyn, V.V. Soboleva
TPU, Tomsk, Russia

Funding: This work is particularly supported by grant of Russian MES Program "Nauka" number 2456
The ability to use a radiation of relativistic electrons in optical fibers for beam diagnostics was proposed by X. Artu recently *. In the cited work the properties of different types of radiation, such as diffraction and Cherenkov radiation in the visible region, induced in fibers by relativistic electron were considered. In our report we present the results of experimental investigation of such a phenomenon for millimeter wavelength radiation. The origin and properties of radiation in fibers were investigated for different geometries of fiber position in respect to the electron beam. The spectral characteristics and dependence on the orientation angle of fibers relative to the electron beam were investigated. One of the useful properties of fibers is the fiber flexibility. The characteristics of radiation accepted by flexible fiber with diameter D=11 mm and length L=600 mm were investigated as a function of curvature radius of the fiber R. The experimental results show the allowable transport factor of radiation for the condition L>R>>D. We believe that fibers for mm and submm range can be used for beam diagnostics also.
* X Artru and C. Ray, Nucl. Inst. Meth. B 309 (2013)

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME158

Export •

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

THPME159

Double Diffraction Radiation Target Interferometry for Micro-train Beam Diagnostics

target, radiation, diagnostics, detector

3635

D.A. Shkitov, A. Potylitsyn
TPU, Tomsk, Russia
A.S. Aryshev, J. Urakawa
KEK, Ibaraki, Japan

Funding: This work was supported by grant of Russian Ministry of Education and Science program “Nauka” number 2.1799.2011.
Recently our group starts to investigate a feasibility of double diffraction radiation (DR) target interferometry for non-invasive micro-train beam diagnostics at KEK: LUCX facility. Double DR target consists of two metal plates and one of them can be moved relative to another along the beam trajectory. Micro-train beam is a sequence of short electron bunches with sub-ps spacing. As it was shown* double DR target can be used for such a beam diagnostics measuring DR yield versus plates displacement. The obtained tuning curve (interferogram) allows to determine a number of bunches within the micro-train and spacing between them. In order to design a reliable device for this aim we have to take into account different double DR target interferometer plate’s adjustment inaccuracies. These inaccuracies can be as follows: inaccuracies in the mutual adjustment of plates tilt angles to the beam trajectory, outer plate edge shift along the beam trajectory and other. The influence of the bunch form-factor shape is also considered. We investigated double DR target preparation accuracy requirements in order to minimize measurements uncertainties and increase interferometer resolution.
* Skitov D.A. et. al., J. Phys.: Conf. Ser. 517, 012024 (2014).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME159

Export •

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

THPME170

Prospects for Longitudinal Phase-space Measurements at the MAX IV Linac

linac, FEL, simulation, extraction

3665

F. Curbis, O. Karlberg, S. Thorin, S. Werin
MAX-lab, Lund, Sweden

Knowing the longitudinal phase space of an electron beam is one of the most important and crucial issues in short-pulses linacs. To achieve this task expensive and rather complicated setups (like transverse deflecting cavities) are usually implemented. The MAX IV 3 GeV linac will be used to inject into two rings and to drive a short pulse facility. Nevertheless, a more deep understanding of the beam quality would be useful especially in view of an upgrade as FEL driver. Another interesting aspect is to evaluate how the double-achromat bunch compressors are performing. We are studying how to implement off-phase acceleration: last part of the linac will be set at zero-crossing phase and the transfer line to the 3 GeV ring could be used as energy spectrometer to retrieve the bunch profile. In the present configuration of the MAX IV linac this procedure will allow to check the bunch length after the first bunch compressor. Since it is work in progress, in this contribution we present a sketch of the measurement and the feasibility of the method will be explored by means of simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME170

Export •

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

THPME171

General-purpose Spectrometer for Vacuum Breakdown Diagnostics for the 12 GHz Test Stand at CERN

vacuum, simulation, klystron, diagnostics

3668

M. Jacewicz, Ch. Borgmann, J. Ögren, R.J.M.Y. Ruber, V.G. Ziemann
Uppsala University, Uppsala, Sweden

Funding: This work is supported by the grants from the the Swedish Research Council DNR-2011-6305 and DNR-2009-6234.
We discuss a spectrometer to analyze the electrons and ions ejected from a high-gradient CLIC accelerating structure that is installed in the klystron-driven 12 GHz test-stand at CERN. The charged particles escaping the structure provide useful information about the physics of the vacuum breakdown within a single RF pulse. The spectrometer consists of a dipole magnet, a pepper-pot collimator, a fluorescent screen and a fast camera. This enables us to detect both transverse parameters such as the emittance and longitudinal parameters such as the energy distribution of the ejected beams. We can correlate these measurements with e.g. the location of the breakdown inside the structure, by using information from the measured RF powers, giving in that way a complete picture of the vacuum breakdown phenomenon. The spectrometer was installed during Spring 2014 and will be commissioned during Summer 2014.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME171

Export •

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

THPME172

Experimental Results from the Characterization of Diamond Particle Detectors with a High Intensity Electron Beam

detector, experiment, radiation, impedance

3671

F. Burkart, R. Schmidt, O. Stein, D. Wollmann
CERN, Geneva, Switzerland
E. Griesmayer
CIVIDEC Instrumentation, Wien, Austria

Understanding the sources of ultra-fast failures, with durations of less than 3 LHC turns, is important for a safe operation of the LHC, as only passive protection is possible in these time scales. Diamond particle detectors with bunch-by-bunch resolution and high dynamic range have been successfully used to improve the understanding of some new ultra-fast loss mechanisms discovered in the LHC. To fully exploit their potential, diamond detectors were characterized with a high-intensity electron beam (10⁵ to 1010 electrons per shot). For the first time their efficiency and linearity has been measured in such a wide range of intensities. In this paper the experimental setup will be described and the signals of the different detectors will be discussed. Finally, future applications of these detectors in high-radiation applications will be discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME172

Export •

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

THPME174

High-accuracy Diagnostic Tool for Electron Cloud Observation in the LHC based on Synchronous Phase Measurements

cryogenics, operation, simulation, synchrotron

3677

J.F. Esteban Müller, P. Baudrenghien, T. Mastoridis, E.N. Shaposhnikova, D. Valuch
CERN, Geneva, Switzerland

Electron cloud effects such as heat load in the cryogenic system, pressure rise and beam instabilities are among the main limitations for the LHC operation with 25 ns spaced bunches. A new observation tool was developed to monitor the e-cloud activity and has been successfully used in the LHC during Run 1 (2010-2012). The power loss of each bunch due to the e-cloud can be estimated using very precise bunch-by-bunch measurement of the synchronous phase shift. In order to achieve the required accuracy, corrections for reflection in the cables and some systematic errors need to be applied followed by a post-processing of the measurements. Results show clearly the e-cloud build-up along the bunch trains and its evolution during each LHC fill as well as from fill to fill. Measurements during the 2012 LHC scrubbing run reveal a progressive reduction in the e-cloud activity and therefore a decrease in the secondary electron yield (SEY). The total beam power loss can be computed as a sum of the contributions from all bunches and compared with the heat load deposited in the cryogenic system. The plan to use this method in the LHC operation is also presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME174

Export •

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

THPME176

CERN Antiproton Decelerator Beam Instrumentation for the ELENA Era

antiproton, pick-up, operation, instrumentation

3684

M. Ludwig, L. Bojtár, M.F. Fernandes, M. Gąsior, L. Søby, G. Tranquille
CERN, Geneva, Switzerland

CERN is currently constructing an Extra Low ENergy Antiproton ring (ELENA), which will allow the further deceleration of antiprotons from the currently exploited Antiproton Decelerator (AD). In order to meet the challenges of ELENA the beam instrumentation systems of the CERN AD are being consolidated and upgraded. An updated controls architecture with a more flexible timing system needs to be adopted and obsolete systems must be replaced. This paper presents the status and plans for improved performance and measurement availability of the AD beam instrumentation with a decreased risk of failure.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME176

Export •

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

THPME179

Beam Diagnostics Measurements at 3MeV of the LINAC4 H⁻ Beam at CERN

linac, emittance, DTL, quadrupole

3694

F. Zocca, J.C. Allica Santamaria, M. Duraffourg, G.J. Focker, D. Gerard, B. Kolad, L. Lenardon, M. Ludwig, U. Raich, F. Roncarolo, M. Sordet, J. Tan, J. Tassan-Viol, C. Vuitton
CERN, Geneva, Switzerland
A. Feschenko
MIPT, Dolgoprudniy, Moscow Region, Russia
A. Feschenko
RAS/INR, Moscow, Russia

As part of the CERN LHC injector chain upgrade, LINAC4 will accelerate H⁻ ions to 160 MeV, replacing the old 50 MeV proton linac. The ion source, the Low Energy Beam Transfer (LEBT) line, the 3 MeV Radio Frequency Quadrupole and the Medium Energy Beam Transfer (MEBT) line hosting a chopper, have been first commissioned in a dedicated test stand and are now tested in the LINAC4 tunnel. Diagnostics devices are installed in the LEBT and MEBT line and in a movable diagnostics test bench which is temporarily added to the MEBT exit. The paper gives an overview of all the instruments used, including beam current transformers, beam position monitors, wire scanners and wire grids for transverse profile measurements, a longitudinal bunch shape monitor and a slit-and-grid emittance meter. The movable test bench also includes a spectrometer that allows measuring the beam energy spread in conjunction with a wire grid. The present understanding of the instrumentation performance is discussed and the measurement results that allowed characterizing the 3 MeV beam in the LINAC4 tunnel are summarized.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME179

Export •

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

THPME180

Vibration Measurement Experiment at TLS

photon, interface, operation, synchrotron

3697

C.C. Liang, C.K. Chou, S. Fann, C.K. Kuan, D. Lin, T.F. Lin, Y.-C. Liu, T.-C. Yu
NSRRC, Hsinchu, Taiwan
Y.-C. Liu
NTHU, Hsinchu, Taiwan

The oncoming completion of Taiwan Photon Source is closely constructed beside Taiwan Light Source (TLS). Few civil works are continuously under construction. Building the measurement, recording and analysis platform of software and hardware is the one of the main directions of operation group. To diagnose the instability problem of the light source, the external influence must be eliminated. One of the factors causing the instability is the physical vibration. Vibration measurement helps to evaluate if newly installed equipments are suited for adding on or the influence of the earthquake to the stability of TLS and to improve the light source quality for users. Software has been developed to provide assistance to do some preliminary diagnoses at TLS. In this article, some actual cases in routine operation are also presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME180

Export •

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

THPME188

Using Principal Component Analysis to Find Correlations and Patterns at Diamond Light Source

storage-ring, data-analysis, vacuum

3719

C. Bloomer, G. Rehm
DLS, Oxfordshire, United Kingdom

Principal component analysis is a powerful data analysis tool, capable of reducing large complex data sets containing many variables. Examination of the principal components set allows the user to spot underlying trends and patterns that might otherwise be masked in a very large volume of data, or hidden in noise. Diamond Light Source archives many gigabytes of machine data every day, far more than any one human could effectively search through for correlations. Presented in this paper are some of the results from running principal component analysis on years of archived data in order to find underlying correlations that may otherwise have gone unnoticed. The advantages and limitations of the technique are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME188

Export •

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

THPME189

Simulation Studies of Diffraction Radiation

radiation, target, simulation, damping

3722

T. Aumeyr, R. Ainsworth, P. Karataev
Royal Holloway, University of London, Surrey, United Kingdom
M.G. Billing
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
L.M. Bobb, B. Bolzon, T. Lefèvre, S. Mazzoni
CERN, Geneva, Switzerland

Transition Radiation (TR) and Diffraction Radiation (DR) are produced when a relativistic charged particle moves through a medium or in the vicinity of a medium respectively. The target atoms are polarised by the electric field of the charged particle, which then oscillate thus emitting radiation with a very broad spectrum. The spatial-spectral properties of TR/DR are sensitive to various electron beam parameters. Several projects aim to measure the transverse (vertical) beam size using TR or DR. This paper reports on recent studies using Zemax, presenting studies on finite beam sizes and the orientation of the beam ellipse.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME189

Export •

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

THPME192

Assembly and Installation of Beam Instrumentation for the ASTA Front-end Diagnostic Table

diagnostics, target, laser, gun

3732

D.J. Crawford, R. Andrews, B.J. Fellenz, D. Franck, T.W. Hamerla, J. Ruan, D. Snee
Fermilab, Batavia, Illinois, USA

Funding: This work was supported by the Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
Early stages of commissioning the Advanced Superconducting Test Accelerator (ASTA) at Fermilab have begun. The Front-end consists of a 1.5 cell normal conducting RF gun resonating at 1.3 GHz with a gradient of up to 40 MV/m, a cesium telluride cathode for photoelectron production, a pulsed 264 nm ultra-violet (UV) laser delivery system, and a Diagnostic Table upon which instrumentation is mounted for measuring the characteristics of the photoelectron beam. We report on the design, construction, and early experience with the Diagnostic Table.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME192

Export •

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

THPME196

Low Energy Coded Aperture Performance at the CesrTA x-Ray Beam Size Monitor

detector, synchrotron, photon, operation

3741

D.P. Peterson, J.P. Alexander, A. Chatterjee, M. P. Ehrlichman, B.K. Heltsley, A. Lyndaker, N.T. Rider, D. L. Rubin, R.D. Seeley, J.P. Shanks
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J.W. Flanagan
KEK, Ibaraki, Japan

Funding: U.S. National Science Foundation PHY-0734867, PHY-1002467, PHYS-1068662, U.S. Department of Energy DE-FC02-08ER41538, DE-SC0006505
We report on the design and performance of coded aperture optics elements in the CesrTA x-ray beam size monitor (xBSM). Resolution must be sufficient to allow single-turn measurements of vertical beam sizes of order 10um by imaging synchrotron radiation photons onto a one-dimensional photodiode array. Measurements with beam energies above 2.1GeV and current above 0.1mA can be performed with a single-slit (pinhole) optic. At lower energy or current, small beam size measurements are limited by the diffractive width of a pinhole image and counting statistics. A coded aperture is a multi-slit mask that can improve on the resolution of a pinhole in two ways: higher average transparency improves counting statistics; and the slit pattern and masking transparency can be designed to obtain a diffractive image with narrower features. We have previously implemented coded apertures that are uniform redundant arrays (URA). A new coded aperture design is optimized for imaging with 1.8 GeV beam energy (1.9keV average x-ray energy) and with beam sizes below 20um. Resolution measurements were made in December 2013. Performance of the new coded aperture is compared to the pinhole and the URA.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME196

Export •

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

THPRI013

A Beam Driven Plasma-wakefield Linear Collider from Higgs Factory to Multi-TeV

plasma, acceleration, positron, linear-collider

3791

J.-P. Delahaye, E. Adli, S.J. Gessner, M.J. Hogan, T.O. Raubenheimer
SLAC, Menlo Park, California, USA
W. An, C. Joshi, W.B. Mori
UCLA, Los Angeles, California, USA

An updated design of a beam-driven Plasma Wake-Field Acceleration Linear Collider (PWFA-LC) covering a wide range of beam collision energy from Higgs factory to multi-TeV is presented. The large effective accelerating field on the order of 1 GV/m and high wall-plug to beam power transfer efficiency of the beam driven plasma technology in a continuous operation mode allows to extend linear colliders to unprecedented beam collision energies up to 10 TeV with reasonable facility extension and power consumption. An attractive scheme of an ILC energy upgrade using the PWFA technology in a pulsed mode is discussed. The major critical issues and the R&D to address their feasibility in dedicated test facilities like FACET and FACET2 are outlined, especially the beam quality preservation during acceleration and the positron acceleration. Finally, a tentative scenario of a series of staged facilities with increasing complexity starting with short term application at low energy is developed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI013

Export •

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

THPRI015

DAΦNE Transfer Line for KLOE-2 Physics Run

injection, controls, linac, detector

3797

A. De Santis, B. Buonomo, S. Cantarella, P. Ciuffetti, G. Di Pirro, A. Drago, L.G. Foggetta, A. Ghigo, C. Milardi, R. Ricci, U. Rotundo, M. Serio, A. Stecchi, A. Stella
INFN/LNF, Frascati (Roma), Italy
A. Michelotti
Consorzio Laboratorio Nicola Cabibbo, Frascati, Italy

The transfer lines of the DAΦNE accelerator complex have been revised and optimized in view of the forthcoming KLOE-2 physics run. The transfer lines consolidation activities involved low level systems, diagnostics tools and control system hardware modifications for the magnetic element switching polarity during the injection procedure. Transfer lines optics has been reviewed and optimized as well by a systematic study based on a MAD-X model. The work done determined a substantial improvement in the transfer lines stability and reproducibility, speeded up the injection procedure with a considerable reduction on the background hitting the experimental detector during the beam injection process.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI015

Export •

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

THPRI024

Finding Your Happy-User-Index

operation, proton, target, feedback

3816

A. Lüdeke
PSI, Villigen PSI, Switzerland

Reliability is defined as the ability of a system or component to perform its required functions under stated conditions for a specified period of time. If we are talking about accelerator reliability then we have to know what the required functions are. Many accelerator facilities restrict their analysis to the beam availability: how reliable is beam provided to the users? We will show that this metrics is often not fully adequate. Specific metrics can be much more useful to allow you to optimize your facility to the needs of your users. The three accelerator user facilities at PSI will serve as examples for these happy-user-indexes.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI024

Export •

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

THPRI031

Design and Commissioning of S-Band RF Station for AREAL Test Facility

gun, LLRF, operation, klystron

3834

A. Vardanyan, H. Avdishyan, H. Davtyan, B. Grigoryan, L.H. Hakobyan, H. Poladyan
CANDLE SRI, Yerevan, Armenia

The RF station has been designed and constructed for AREAL Linac. The constructional features and commissioning results of RF system are presented. The whole RF system is designed to work at 3GHz frequency. The linac includes an electron gun for 0.5-8 ps electron bunch production with 1-10 Hz repetition rate. For linac RF control system a Libera LLRF stabilization system is used. An important feature of the presented system is a high level synchronization of amplitude-phase characteristics which provide the required accuracy for particle acceleration and bunch formation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI031

Export •

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

THPRI033

Design of New Buncher Cavity for Relativistic Electron Gun for Atomic Exploration – REGAE

cavity, simulation, emittance, operation

3840

M. Fakhari, H. Delsim-Hashemi, K. Flöttmann, M. Hüning, S. Pfeiffer, H. Schlarb
DESY, Hamburg, Germany
J. Roßbach
Uni HH, Hamburg, Germany

The Relativistic Electron Gun for Atomic Exploration, REGAE, is a small electron accelerator build and operated at DESY. Its main application is to provide high quality electron bunches for time resolved diffraction experiments. The RF system of REGAE contains different parts such as low level RF, preamplifier, modulator, phase shifter, and cavities. A photocathode gun cavity to produce the electrons and a buncher cavity to compress the electron bunches in the following drift tube. Since the difference between the operating mode of the existing buncher and its adjacent mode is too small, the input power excites the other modes in addition to the operating mode which affects the beam parameters. A new buncher cavity is designed in order to improve the mode separation. Furthermore the whole cavity is modeled by a circuit which can be useful especially during the tuning process. Beam dynamics simulations have been performed in order to compare the new designed cavity with the old one which declare that the effects of the adjacent modes on the beam parameters are decreased.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI033

Export •

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

THPRI035

Design and Simulation of Side Coupled Six MeV Linac for X-Ray Cargo Inspection

cavity, coupling, acceleration, simulation

3844

S. Ahmadiannamin, F. AbbasiDavani, R. Ghaderi, F. Ghasemi
sbu, Tehran, Iran
M. Lamehi Rashti
IPM, Tehran, Iran
S. Zarei
Nuclear Science and Technology Research, InstituteRadiation Application School, Tehran, Iran

Using in X-ray cargo inspection is one of most applications of linear accelerators. This paper represents design and simulation of Side Coupled Six MeV cavity. The electromagnetic simulation of structure was carried out in the SUPERFISH and CST Microwave studio. 2.3 MW input power is considered according to MG5193 magnetron. The coupling coefficient is calculated equal to 3% for stabilization of accelerator operation against environmental and mechanical errors effects.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI035

Export •

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

THPRI038

Simulation Study of Electron Gun for Six MeV Linac for X-Ray Cargo Inspection

gun, simulation, cathode, focusing

3847

S. Ahmadiannamin, F. AbbasiDavani, R. Ghaderi, F. Ghasemi
sbu, Tehran, Iran
M. Lamehi Rashti
IPM, Tehran, Iran
S. Zarei
Nuclear Science and Technology Research, InstituteRadiation Application School, Tehran, Iran

Electron guns are designed in different models. Output beam quality and efficiency of the linear accelerator for each application depends on choosing the suitable model of electron gun. The most common types are diode and triode electron guns. Simulation Study of diode electron gun of Six MeV Linac for X-Ray Cargo Inspection represented in this article. Vaughan analytical method was used to obtain the initial dimensions. In final stage, CST Particle Studio software used to obtain the dimensional details.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI038

Export •

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

THPRI040

Study of Geometrical Parameters and their Tolerances in Optimization of Accelerating Cells of Side Coupled Linac

cavity, linac, simulation, impedance

3850

S. Zarei
Nuclear Science and Technology Research, InstituteRadiation Application School, Tehran, Iran
F. AbbasiDavani, S. Ahmadiannamin, F. Ghasemi
sbu, Tehran, Iran
M. Lamehi Rashti
IPM, Tehran, Iran

After choosing the suitable geometry for accelerating cavity, evaluation of geometrical parameters effects on radio frequency characteristics is essential. In this paper after study of priority of geometrical parameters in optimization of accelerating cells of Side Coupled Linac, according to obtained results, new design of s-band accelerating cavity is suggested. By frequency sensitivity study of new dimensions, we can choose best technique to tune the accelerating cavity during magnetic coupling-hole adjustment.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI040

Export •

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

THPRI044

Vacuum Waveguide System for SPring-8 Linac Injector Section

vacuum, linac, klystron, operation

3863

T. Taniuchi, H. Dewa, H. Hanaki, T. Kobayashi, T. Magome, A. Mizuno, S. Suzuki, K. Yanagida
JASRI/SPring-8, Hyogo-ken, Japan

An SF6 waveguide system for the injector section of SPring-8 linac has been replaced in a vacuum waveguide system including a newly developed vacuum circulator and an isolator. This paper describes developed RF components, a waveguide configuration and an RF conditioning of the system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI044

Export •

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

THPRI048

Design of an Accelerating Tube for a Standing-wave Accelerator based on Genetic Algorithm’s Optimal Calculation

impedance, coupling, simulation, radiation

3875

Z.X. Tang
USTC, Hefei, Anhui, People's Republic of China
Y.J. Pei
USTC/NSRL, Hefei, Anhui, People's Republic of China

A compact medical standing-wave (SW) electron accelerating tube has been designed that operating frequency is 2998MHz, operating mode is π/2, final energy is 6MeV and beam current is 100mA based on genetic algorithm (GA)’s optimal calculation. It employed a bi-periodic structure with nose cone shape. We performed the simulation experiment which proved that GA was feasible and gave a set of geometric parameter with higher shunt impedance. We performed tuning of the whole tube by CST MICROWAVE STUDIO and SUPERFISH and calculation of beam dynamics by ASTRA and Parmela in this paper. The total length of the tube is less than 300mm.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI048

Export •

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

THPRI055

The New 118 MHz Normal Conducting RF Cavity for SIAM Photon Source at SLRI

cavity, storage-ring, impedance, HOM

3896

N. Juntong, S. Krainara
SLRI, Nakhon Ratchasima, Thailand

The Siam Photon Source (SPS) is the 1.2 GeV second generation light source in Thailand. It is managed by the Synchrotron Light Research Institute (SLRI). The institute is located inside the campus of Suranaree University of Technology (SUT), which is approximately 20 km from the city of Nakhon Ratchasima (or normally called Korat). Korat is 250 km north-east of Bangkok. Two insertion devices (IDs) have been installed in the SPS storage ring during June to August 2013. These IDs require additional electrical field energy from RF cavity to compensate electron energy loss in the storage ring. The existing RF cavity has been pushed to its maximum capability and the new RF cavity is in the procurement process. The design and study of the new RF cavity will be presented. Electromagnetic fields of the cavity are studied together with the effects to electron beam instabilities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI055

Export •

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

THPRI059

Field Emission Study of RF cavity in Static Magnetic Field

cathode, gun, cavity, solenoid

3905

T.H. Luo, D. Li
LBNL, Berkeley, California, USA
W. Gai
ANL, Argonne, Illinois, USA
J.H. Shao
TUB, Beijing, People's Republic of China

The RF cavity performance in solenoid magnetic field is crucial for the muon ionization cooling. Previous experiments have shown that the strong external magnetic field can significantly lower the maximum achievable RF voltage in the cavity. The mechanism of this performance degradation has been studied both analytically and experimentally, but so far no conclusive cause has been determined yet. In this paper, we propose an experiment to study the effect of a static B field on the field emission in the RF cavity, which hasn't been investigated before, and which can contribute to the cavity performance degradation in the solenoid field.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI059

Export •

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

THPRI064

Plasma Chemistry in a High Pressure Gas Filled RF Test Cell for use in a Muon Cooling Channel

ion, plasma, experiment, cavity

3917

B.T. Freemire, Y. Torun
IIT, Chicago, Illinois, USA
M. Chung, M.R. Jana, M.A. Leonova, A. Moretti, T.A. Schwarz, A.V. Tollestrup, Y. Torun, K. Yonehara
Fermilab, Batavia, Illinois, USA
R.P. Johnson
Muons, Inc, Illinois, USA

Filling an RF cavity with a high pressure gas prevents breakdown when the cavity is placed in a multi-Tesla external magnetic field. A beam of particles traversing the cavity, be it muons or protons, ionizes the gas, creating an electron-ion plasma which absorbs energy from the cavity. In order to understand the nature of this plasma loading, a variety of gas species, gas pressures, dopants, and cavity electric fields were investigated. Plasma induced energy loss, electron-ion recombination rates, ion-ion recombination rates, and electron attachment times were measured. The results for hydrogen, deuterium, helium, and nitrogen, doped with dry air will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI064

Export •

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

THPRI071

Instrumentation for Characterizing 201-MHz MICE Cavity at Fermilab

cavity, vacuum, pick-up, instrumentation

3930

M. Chung, D.L. Bowring, A. Moretti, R.J. Pasquinelli, D.W. Peterson, R.P. Schultz
Fermilab, Batavia, Illinois, USA
P.G. Lane, Y. Torun
Illinois Institute of Technology, Chicago, Illinois, USA
L. Somaschini
INFN-Pisa, Pisa, Italy

A 201-MHz single cavity module is installed in the Mucool Test Area (MTA) of Fermilab to test the performance of the cavity at the design parameters for the International Muon Ionization Cooling Experiment (MICE) particularly in multi-Tesla external magnetic fields. To monitor various aspects of the cavity and to understand detailed physics involved in RF breakdown and multipacting, numerous instrumentation is installed on the cavity module and also in the experimental hall, which includes thermocouples, infrared sensors, electron pickups, fiber light guides, and radiation detectors. In this paper, we will present details of each diagnostic and initial test results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI071

Export •

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

THPRI073

Achieving Higher Energies via Passively Driven X-band Structures

cavity, impedance, linac, FEL

3933

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

Due to their higher intrinsic shunt impedance X-band accelerating structures significant gradients with relatively modest input powers, and this can lead to more compact particle accelerators. At the Colorado State University Accelerator Laboratory (CSUAL) 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 design details of the X-band structures that will allow us to achieve our goal of reaching the maximum practical net potential across the X-band accelerating structure while driven solely by the beam from the L-band system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI073

Export •

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

THPRI074

Colorado State University (CSU) Accelerator and FEL Facility

laser, controls, linac, undulator

3937

S. Biedron, C. Carrico, A. D'Audney, J.P. Edelen, J. Einstein, C.C. Hall, J.R. Harris, K. Horovitz, J. Martinez, S.V. Milton, A.L. Morin, N. Sipahi, T. Sipahi, J.E. Williams, P.J.M. van der Slot
CSU, Fort Collins, Colorado, USA
P.J.M. van der Slot
Mesa+, Enschede, The Netherlands
P.J.M. van der Slot
Twente University, Laser Physics and Non-Linear Optics Group, Enschede, The Netherlands

The Colorado State University (CSU) Accelerator Facility will include a 6-MeV L-Band electron linear accelerator (linac) with a free-electron laser (FEL) system capable of producing Terahertz (THz) radiation, a laser laboratory, a microwave test stand, and a magnetic test stand. The photocathode drive linac will be used in conjunction with a hybrid undulator capable of producing THz radiation. Details of the systems used in CSU Accelerator Facility are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI074

Export •

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

THPRI079

RF BREAKDOWN IN A GAS-FILLED TE01 CAVITY

cavity, plasma, klystron, simulation

3952

F.Y. Wang, C. Adolphsen, C.D. Nantista
SLAC, Menlo Park, California, USA

An L-band (1.3 GHz) TE01 mode pillbox cavity has been designed to study rf breakdown in gas. Since there are no surface electric fields, effects from the electron interaction with the surface should not be present as in the DC breakdown case. A CCD camera was used to measure the integrated light pattern through holes in the cavity, and an ultrafast diode was used to observed the evolution of the plasma during breakdown. Some preliminary results of the tests are presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI079

Export •

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

THPRI080

The New Design for Capture Cavity of CEBAF

cavity, coupling, acceleration, simulation

3955

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

In CEBAF, the electron beam from the injector must be sufficiently relativistic to match a 1 GeV recirculated beam in the first linac. The electron beam is produced with a ~130 keV electron gun, then accelerated by a room temperature, graded-beta standing wave linac, capture section, from 130 keV to 510 keV before enters two 5-cell superconducting RF cavities for further acceleration. Present capture cavity is a 5-cell side-coupled cavity. We designed a new slot-coupled cavity which has lower power consumption and simpler structure.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI080

Export •

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

THPRI081

A Transverse Electron Target for Heavy Ion Storage Rings

ion, target, quadrupole, ion-source

3958

S. Geyer, O.K. Kester, O. Meusel
IAP, Frankfurt am Main, Germany
O.K. Kester
GSI, Darmstadt, Germany

A transverse electron target already constructed is under investigation for the application in storage rings at the FAIR facility. Using a sheet beam of free electrons in a crossed beam geometry promises a high energy resolution and gives access to the interaction region for spectroscopy. The produced electron beam has a length of 10 cm in ion beam direction and a width of 5 mm in the interaction region with electron densities of up to 10⁹ electrons/cm³. The target allows the adjustment of the electron beam current and energy in the region of several 10 eV and a few keV. Simulations have been performed regarding the energy resolution for electron-ion collisions. Also the ion optical behaviour of the target was investigated numerically. The target is integrated in a test bench to study the performance of the electron gun and the electron beam optics. The installed volume ion source delivers light ions and molecules for characterization of the target performance by measuring charge changing processes. Subsequently the target will be installed temporarily at the Frankfurt Low-Energy Storage Ring (FLSR) for further test measurements. An overview of the project status will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI081

Export •

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

THPRI084

Testing Results of the Prototype Beam Absorber for the PXIE MEBT

focusing, radiation, simulation, experiment

3967

C.M. Baffes, A.V. Shemyakin
Fermilab, Batavia, Illinois, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the United States Department of Energy
One of the goals of the PXIE program at Fermilab is to demonstrate the capability to form an arbitrary bunch pattern from an initially CW 162.5 MHz H⁻ bunch train coming out of an RFQ. The bunch-by-bunch selection will take place in the 2.1 MeV Medium Energy Beam Transport (MEBT) by directing the undesired bunches onto an absorber that needs to withstand a beam power of up to 21 kW, focused onto a spot with a ~2 mm rms radius. A prototype of the absorber was manufactured from molybdenum alloy TZM, and tested with an electron beam up to the peak surface power density required for PXIE, 17W/mm2. Temperatures and flow parameters were measured and compared to analysis. This paper describes the absorber prototype and key testing results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI084

Export •

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

THPRI086

Beam Dumps of the New LCLS-II

shielding, neutron, radiation, operation

3973

M. Santana-Leitner, A. Ibrahimov, L.Y. Nicolas, S.H. Rokni, D.R. Walz, J.J. Welch
SLAC, Menlo Park, California, USA

Funding: Work supported by U.S. Department of Energy contract DE-AC02-76SF00515.
In 2013 the design of the new LCLS-II new hard X-FEL facility at the SLAC National Accelerator Laboratory was rescoped to operate two parallel variable gap undulator lines at repetition rates up to 1MHz and above. A new superconducting RF structure will be installed in the first third of the SLAC two-mile Linac to provide a few hundred kWof beam power at energies of up to 4 GeV. This paper describes the radiological aspects of the dumps that are being designed for the end of the electron beam lines. A layered arrangement of shielding materials is being optimized to reduce instantaneous dose leakage to occupied areas, minimum cool-down time to access the tunnel, and impact to equipment and to the environment. Calculations deal with numerous constraints, as legacy beam components will be used, and the existing tunnel structure was designed for beam powers fifty times below those envisaged for LCLS-II.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI086

Export •

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

THPRI091

Machine Protection Considerations for BERLinPro

linac, vacuum, laser, diagnostics

3985

S. Wesch, M. Abo-Bakr, M. Dirsat, G. Klemz, P. Kuske, A. Neumann, J. Rahn, T. Schneegans
HZB, Berlin, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association
The Berlin energy-recovery-linac project BERLinPro at the HZB is a 50 MeV ERL test facility, which addresses physical and technological questions for future superconducting rf based high brightness, high current electron beam sources. The combination of a 100 mA cw beam, electron bunches with normalized emittances lower than 1 mm mrad and the magnet optics of BERLinPro leads to power densities capable to harm the accelerator components within microseconds if total beam loss occurs. Furthermore, continuous beam loss on the level of 10^-5 has to be controlled to avoid activation and to protect the SRF, beam diagnostics and other infrastructure components. In this paper, we present the evaluation of the required key parameters of the BERLinPro machine protection system and present its first conceptual design.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI091

Export •

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

THPRI100

Distributed Cooling System for the AREAL Test Facility

gun, klystron, operation, controls

4010

V. V. Vardanyan, G.A. Amatuni, V.S. Avagyan, A.A. Gevorgyan, B. Grigoryan, T.H. Mkrtchyan, V. Sahakyan, A.S. Simonyan, A.V. Tsakanian, A. Vardanyan
CANDLE SRI, Yerevan, Armenia

Following the design specifications of the Advanced Research Electron Accelerator Laboratory (AREAL), a reliable distributed cooling system for the AREAL linear accelerator has been developed. The cooling system provides a high accuracy temperature control for the electron gun, klystron and the magnets. The main requirements and technical solutions for various accelerator components cooling units are presented, including the local and remote control.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI100

Export •

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

THPRI104

Design and Fabrication of Bunch Compressor Support System for PAL XFEL

dipole, vacuum, diagnostics, quadrupole

4022

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

Pohang Accelerator Laboratory(PAL) is developing a SASE X-ray Free Electron Laser based on 10 GeV linear accelerator. Bunch compressor support systems are developed to be used for the linear accelerator tunnel. The support system design is based on an asymmetric four-dipole magnet chicane in which asymmetry and variable R56. can be optimized. This flexibility is achieved by allowing the middle two dipole magnets to move transversely. Moving system consist of servo motor, rodless ball screw actuator and linear encoder. In this paper, we describe the design of the stages used for precise movement of the bunch compressor magnets and associated diagnostics components.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI104

Export •

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

THPRI114

Apparatus and Technique for Measuring Low RF Resistivity of Tube Coatings at Cryogenic Temperatures

vacuum, cryogenics, cavity, network

4046

A. Hershcovitch, M. Blaskiewicz, J.M. Brennan, J. Brodowski, W. Fischer, R. Than, J.E. Tuozzolo
BNL, Upton, Long Island, New York, USA
A.X. Custer, A.A. Dingus, M.Y. Erickson, N.Z. Jamshidi, H.J. Poole
PVI, Oxnard, California, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
An in-situ technique for coating stainless steel vacuum tubes with Cu was developed to mitigate the problems of wall resistivity that leads to unacceptable ohmic heating of superconducting magnets cold bore and electron cloud generation in RHIC that can limit future machine luminosity enhancement. Room temperature RF resistivity of 10 μm Cu coated stainless steel RHIC beam tube has conductivity close to copper tubing. Before coating the RHIC beam pipe with copper, it is imperative to test the Cu coating’s conductivity at cryogenic. A folded quarter wave resonator structure has been designed and built for insertion in a cryogenic system to measure RF resistivity of copper coated RHIC tubing at liquid helium temperatures. The design is based on making the resonator structure out of a superconducting material such that the copper coating is the most lossy material. RHIC tubing samples prepared with different magnetron sputtering deposition modes are to be optimized by iterative processes. Additionally, this device can also be used for the development of better, cheaper SRF cavities and electron guns. The apparatus and its design details will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI114

Export •

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

FRYBA01

Long-term Accelerator R&D as an Independent Research Field

laser, plasma, SRF, acceleration

4073

R. Brinkmann
DESY, Hamburg, Germany

High energy physics projects have been important drivers of accelerator R&D for several decades. The resulting accelerator technology was used to construct frontier accelerators for HEP but was also very successfully applied in accelerators for other science fields, in particular photon science, nuclear physics, medical applications, … Fewer HEP projects and at the same time a growing number of projects in other areas require a modified approach to accelerator R&D. Efforts and progress to perform accelerator R&D as an independent research program with its own, independent funding are described for the example of the Helmholtz ARD program in Germany. Links to efforts in other countries are discussed and an outlook to future accelerator research is given.

Slides FRYBA01 [3.581 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-FRYBA01

Export •

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