IPAC2014 - List of Keywords (gun)

Paper	Title	Other Keywords	Page
MOZB01	Superconducting RF Guns: Emerging Technology for Future Accelerators	cathode, SRF, cavity, laser	4085
	J. Teichert HZDR, Dresden, Germany
	This talk should give an overview of Superconducting photo injectors (SRF guns) and focus on the present status of SRF gun development, the technical requirements and the critical issues like cavity design, photocathode integration, and emittance compensation methods.
	Slides MOZB01 [22.198 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOZB01
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MOPRO001	Upgrade Status of Injector LINAC for SuperKEKB	positron, electron, linac, emittance	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
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MOPRO013	Present Status of Coherent Electron Cooling Proof-of-Principle Experiment	electron, ion, cavity, 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.
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MOPRO066	Status of FLUTE	laser, electron, 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.
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MOPRO091	Fundamental Limits of Velocity Bunching of High-brightness Electron Beams	bunching, electron, emittance, cavity	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.
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MOPRO106	Status of the HZB ERL Prototype BERLinPro	linac, cavity, SRF, booster	340
	M. Abo-Bakr, W. Anders, R. Barday, K.B. Bürkmann-Gehrlein, A. Burrill, V. Dürr, A. Jankowiak, C. Kalus, T. Kamps, G. Klemz, J. Knobloch, J. Kolbe, O. Kugeler, B.C. Kuske, A.N. Matveenko, A. Meseck, A. Neumann, K. Ott, E. Panofski, D. Pflückhahn, J. Rahn, J. Rudolph, M. Schmeißer, S.G. Schubert, O. Schüler, J. Völker, S. Wesch 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 Prototype BERLinPro is to be constructed at the Helmholtz Zentrum site in Berlin. The aim of the project is to expand the required accelerator physics and technology knowledge mandatory for the generation of a high current (100 mA), high brilliance (norm. emittance below 1 mm mrad) cw electron beam. Since the funding decision in October 2010 the project has entered a phase of detailed planning. Hardware specifications have been defined and various components have been ordered. Furthermore, extensive tests of principal superconducting accelerator components successfully demonstrated the envisaged hardware performance. A summary of the most recent activities together with the details of the project timeline for the coming years are given in this paper.
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MOPRO107	Multi-turn ERL-based Synchrotron Light Facility: Injector Design	emittance, linac, brilliance, booster	343
	A.N. Matveenko, T. Atkinson, A.V. Bondarenko, Y. Petenev HZB, Berlin, Germany
	Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association VH NG 636 and HRJRG-214 Multi-turn energy recovery linac based light sources are candidates for the future 4th generation synchrotron light sources. Using the superconducting linac technology, the Femto-Science-Factory (FSF) will provide its users with ultra-bright photon beams of angstrom wavelength at 6 GeV final beam energy. The FSF is intended to be a multi-user facility and offers a variety of operation modes. An overview of the machine layout and magnetic optics design of the installation will be given in this paper with the focus on high brightness injector design.
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MOPRO112	Energy Recovering for Linac RF Injectors	cavity, SRF, HOM, linac	356
	V. Volkov, Ya.V. Getmanov, O.A. Shevchenko, N. Vinokurov BINP SB RAS, Novosibirsk, Russia A.N. Matveenko HZB, Berlin, Germany
	The article presents a new design of a CW RF high average current superconducting injector cavity. This design allows recovering energy in the injector, improving beam parameters and energy efficiency, reducing injector size, cost, and avoiding high average power coupler problem.
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MOPME008	3d Full Electromagnetic Beam Dynamics Simulations of the Pitz Photoinjector	simulation, laser, cathode, emittance	391
	Y. Chen, E. Gjonaj, W.F.O. Müller, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: work supported by DESY, Hamburg and Zeuthen sites The electromagnetic (EM) simulation software CST STUDIO SUITE® * has been applied to investigate the beam dynamics for the electron gun of the Photo Injector Test facility at DESY, Zeuthen site (PITZ). A series of 3D beam dynamics simulations are performed to study the bunch injection process at PITZ with the objective of clarifying the discrepancies between measurements and simulations. Multiple comparisons are presented for the transverse emittance and the total emitted charge between the measurement data and simulation results using CST STUDIO SUITE®and Astra *. Computer Simulation Technology AG, website: http://www.cst.com/ ** K. Floettmann A Space Charge Tracking Algorithm, user manual (version 3), 2011
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MOPME033	Beam Dynamics in an Electron Lens with the Warp Particle-in-cell Code	electron, simulation, collider, 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.
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MOPME067	Kicker Development at the ELBE Facility	kicker, positron, SRF, electron	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.
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MOPRI017	Status of AREAL RF Photogun Test Facility	electron, 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.
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MOPRI020	Introducing GunLab – A Compact Test Facility for SRF Photoinjectors	electron, 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.
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MOPRI023	Simulation of the ELBE SRF Gun II	simulation, emittance, SRF, laser	636
	P.N. Lu, A. Arnold, U. Lehnert, P. Murcek, J. Teichert, H. Vennekate, R. Xiang HZDR, Dresden, Germany
	Funding: EuCARD, contract number 227579 German Federal Ministry of Education and Research grant 05 ES4BR1/8 LA³NET, Grant Agreement Number GA-ITN-2011-289191 By combining the code of ASTRA and elegant in a user-friendly interface, a simulation tool is developed for the ELBE SRF Gun II. The photoelectric emission and first acceleration to several MeV in the gun cavity are simulated by ASTRA with a 1D Model, where the space charge effect is considered. The dependence of the beam quality on key parameters is studied, and a compromised optimization for a 77 pC beam is used for further elegant simulation of the beam transport through a dogleg and ELBE Linacs. Proper settings of the magnets and RF phases are the main targets of improving the beam quality. Up to now the best simulation result is an electron bunch with the energy of 47 MeV, energy spread of 66 keV, bunch length of 0.35 ps and transverse emittance of 1.9 μm and 2.7 μm in the two perpendicular directions.
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MOPRI024	NEA-GaAs (Cs, O) Photocathodes for the ELBE SRF Gun	vacuum, SRF, cathode, laser	639
	R. Xiang, A. Arnold, P.N. Lu, P. Michel, P. Murcek, J. Teichert, H. Vennekate HZDR, Dresden, Germany
	Funding: supported by the European Community under the FP7 programme (EuCARD-2, contract number 312453, and LA3NET, contract number 289191), and by the BMBF grant 05K12CR1. At HZDR a preparation chamber for NEA-GaAs (Cs, O) has been built and commissioned. GaAs is the next photocathode material for the ELBE SRF gun, which has been successfully operated with Cs2Te layer in last years. GaAs At HZDR a preparation chamber for NEA-GaAs (Cs, O) has been built and tested. GaAs is the next photocathode material for the ELBE SRF gun, which has been successfully operated with Cs2Te photocathode in last years. GaAs photocathodes are advantageous because of their high quantum efficiency (QE) with visible light and the extensive experiences of their use in DC guns. Furthermore, GaAs photocathodes provide the possibility to realize a polarized SRF gun in the future. In this presentation we will introduce the new preparation system and the first results of the GaAs tests. The new transfer system under construction will be also presented.
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MOPRI025	Recent Improvement of Cs2Te Photocathodes at HZDR	cathode, vacuum, SRF, cavity	642
	R. Xiang, A. Arnold, P.N. Lu, P. Michel, P. Murcek, J. Teichert, H. Vennekate HZDR, Dresden, Germany
	Funding: Work supported by the European Community-Research Infrastructure Activity (EuCARD, contract number 227579), and the support of the German Federal Ministry of Education and Research grant 05 ES4BR1/8. The SRF gun has been successfully operated for the radiation source ELBE at HZDR. To achieve higher current and lower beam emittance, a new niobium cavity with superconducting solenoid and a new 13 MHz laser have been recently developed. For this reason, better photocathodes with high quantum efficiency are urgently in demand. In this work we improve the present Cs2Te preparation system for cleaner environment and more precise stoichiometric control than before. A new mask is designed to prevent cesium pollution of the cathode body. Instead of Kapton only alumina ceramics are used for isolation, and the cathode plugs are degassed at higher temperature. New evaporators are installed and tested to obtain an accurate deposition rate. Furthermore, the cathode transfer system is thoroughly cleaned for a better vacuum condition.
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MOPRI027	Dark Current Studies at Relativistic Electron Gun for Atomic Exploration – REGAE	electron, 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.
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MOPRI028	Different Countermeasures of Electron Amplification in the Photocathode Unit	cathode, electron, SRF, 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.
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MOPRI030	Basic Design of a 20K C-band 2.6-cell Photocathode RF Gun	cavity, simulation, electron, 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.
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MOPRI033	Quasi-traveling Wave Side Couple RF Gun Commissioning for SuperKEKB	cavity, emittance, cathode, coupling	667
	T. Natsui, Y. Ogawa, M. Yoshida, X. Zhou KEK, Ibaraki, Japan
	We are developing a new RF gun for SuperKEKB. High-charge low-emittance electron and positron beams are required for SuperKEKB. We will generate 7.0 GeV electron beam at 5 nC 20 mm-mrad by J-linac. In this linac, a photo cathode S-band RF gun will be used as the electron beam source. For this reason, we are developing an advanced RF gun. New RF gun which has two side coupled standing wave field is developed. We call it quasi traveling wave side couple RF gun. This gun has a strong focusing field at the cathode and the acceleration field distribution also has a focusing effect. Beam commissioning has been started with the new RF gun. I will report the result of beam commissioning.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI033
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MOPRI036	Pulse Radiolysis Using Terahertz Probe Pulses	electron, laser, radiation, 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).
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MOPRI037	Development of Iridium Cerium Photocathode for the Generation of High-Charge Electron Beam	laser, electron, cathode, 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.
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MOPRI039	Ultra-short Electron Bunch Generation using Energy-chirping Cell Attached RF Electron Gun	electron, 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.
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MOPRI040	Design and Analysis of an Electron Beam in an Electron Gun for X-Ray Radiotherapy	electron, 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.
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MOPRI041	Electrons Injectors with Cathode Diameter of 6/15mm and New Cup Energy Input on the Wave E11 for Accelerators	cathode, electron, Windows, 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".
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MOPRI043	Study of a C-band Standing-wave Gun for the SwissFEL Injector	cathode, solenoid, coupling, emittance	698
	M. Schaer, S. Bettoni, A. Citterio, P. Craievich, M. Negrazus, L. Stingelin, R. Zennaro PSI, Villigen PSI, Switzerland
	The baseline design of the SwissFEL injector foresees the "PSI Gun 1", a 2.6-cell RF photo-cathode gun operating at S-band frequency, as the electron source. In this paper a new design is presented where a 5.6-cell C-band gun could replace the PSI Gun 1 with no impact on the rest of the injector setup. A conservative maximum gradient of 135 MV/m at the cathode is assumed which drives the electron beam faster into the relativistic regime and therefore allows to tolerate larger charge densities. The presented solution also foresees a coaxial RF coupling from the cathode side in order to place the gun solenoid as near to the photo-cathode as possible, improving the emittance compensation. Astra simulations showed that the transverse beam brightness can be doubled before the first bunch compressor preserving the low transverse emittance value as compared to the current design for the S-band injector configuration of SwissFEL.
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MOPRI044	Feasibility Study of an Ultrafast Electron Diffraction System in NSRRC	electron, 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.
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MOPRI045	Beam Diagnostics E-GUN Test Stand at TARLA	electron, 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
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MOPRI047	The Preparation of Atomically Clean Metal Surfaces for use as Photocathodes in Normally Conducting RF Guns	ion, plasma, laser, electron	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.
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MOPRI053	High Repetition Rate Ultrafast Electron Diffraction at LBNL	electron, emittance, 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.
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MOPRI054	Status of the APEX Project at LBNL	cathode, cavity, FEL, linac	727
	F. Sannibale, K.M. Baptiste, C.W. Cork, J.N. Corlett, S. De Santis, L.R. Doolittle, J.A. Doyle, D. Filippetto, G.L. Harris, G. Huang, H. Huang, R. Huang, T.D. Kramasz, S. Kwiatkowski, R.E. Lellinger, V. Moroz, W.E. Norum, C. F. Papadopoulos, G.J. Portmann, H.J. Qian, J.W. Staples, M. Vinco, S.P. Virostek, R.P. Wells, M.S. Zolotorev LBNL, Berkeley, California, USA R. Huang USTC/NSRL, Hefei, Anhui, 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 Advanced Photo-injector EXperiment (APEX) at the Lawrence Berkeley National Laboratory (LBNL), consists in the development of an injector designed to demonstrate the capability of the VHF gun, a normal conducting 186 MHz RF gun operating in CW mode, to deliver the brightness required by X-ray FEL applications at MHz repetition rate. APEX is organized in 3 main phases where different aspects of the required performance are gradually demonstrated. The status and future plans for the project are presented.
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MOPRI055	APEX Present Experimental Results	cathode, electron, 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.
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MOPRI056	Design and Fabrication of a VHF - CW High Repetition Rate Electron Gun	cavity, cathode, vacuum, operation	733
	R.P. Wells, B. Ghiorso, F. Sannibale, J.W. Staples LBNL, Berkeley, California, USA T.M. Huang IHEP, 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 A high repetition rate, MHz, electron source is a key element in future FEL based light sources. The Advance Photo-injector Experiment (APEX) at Lawrence Berkeley National Laboratory (LBNL) consists of a high repetition rate 186 MHz (VHF-band) CW electron gun, 1 MHz UV laser source and the diagnostic components necessary to quantify the gun’s performance. The gun design is based on well established, conventional RF cavity design, with a couple notable exceptions. The basis for the selection of this technology, novel design features, fabrication techniques and measured cavity performance are presented.
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MOPRI059	Fabrication of Alkali Antimonide Photocathode for SRF Gun	cathode, laser, vacuum, SRF	742
	E. Wang, S.A. Belomestnykh, I. Ben-Zvi, D. Kayran, G.T. McIntyre, T. Rao, J. Smedley, D. Weiss, W. Xu BNL, Upton, Long Island, New York, USA I. Ben-Zvi, M. Ruiz-Osés Stony Brook University, Stony Brook, USA X. Liang SBU, Stony Brook, New York, USA H.M. Xie PKU, Beijing, People's Republic of China
	Funding: * This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE and DOE grant The first alkali antimonide photocathode was prepared and inserted into the BNL 704 MHz SRF gun. An excimer laser cleaning system was installed in a cathode deposition chamber and the cleaning technique developed previously was used in the first cathode preparation. We also demonstrated that oxidized cathode can be removed by exposing it to the same excimer laser. In this paper, we show the set up of the incorporated laser cleaning system and the QE enhancement of alkali antimony photocathode. The vacuum evolution at transport cart and QE measurement system are also discussed.
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MOPRI063	Alkali Antimonide Photocathodes in a Can	cathode, vacuum, insertion, controls	745
	J. Smedley, K. Attenkofer, T. Rao, S.G. Schubert BNL, Upton, Long Island, New York, USA I. Ben-Zvi, X. Liang, E.M. Muller, M. Ruiz-Osés Stony Brook University, Stony Brook, USA J. DeFazio PHOTONIS USA Pennsylvanis, Inc., Lancaster, Pennsylvania, USA H.A. Padmore, J.J. Wong LBNL, Berkeley, California, USA J. Xie ANL, Argonne, Illinois, USA
	Funding: Work was supported by the US DOE, under Contracts DE-AC02-05CH11231, DE-AC02-98CH10886, KC0407-ALSJNT-I0013, DE-FG02-12ER41837 and DE-SC0005713. Use of CHESS is supported by NSF award DMR-0936384. The next generation of x-ray light sources will need reliable, high quantum efficiency photocathodes. These cathodes will likely be from the alkali antimonide family, which currently holds the record for highest average current achieved from a photoinjector. In this work, we explore a new option for delivering these cathodes to a machine which requires them: use of sealed commercial vacuum tubes. Several sealed tubes have been introduced into a vacuum system and separated from their housing, exposing the active photocathode on a transport arm suitable for insertion into a photoinjector. The separation has been achieved without loss of QE. These cathodes are compared to those grown via traditional methods, both in terms of QE and in terms of crystalline structure, and found to be similar.
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MOPRI064	First Test Results from SRF Photoinjector for the R&D ERL at BNL	SRF, cathode, cavity, electron	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.
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MOPRI073	Status of the HESR Electron Cooler Test Set-up	electron, 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.
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MOPRI075	COSY 2 MeV Cooler: Design, Diagnostic and Commissioning	electron, controls, 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.
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TUOCA02	Status of the Free Electron Laser User Facility FLASH	FEL, flattop, laser, linac	938
	M. Vogt, B. Faatz, J. Feldhaus, K. Honkavaara, S. Schreiber, R. Treusch DESY, Hamburg, Germany
	FLASH, the Free Electron Laser User Facility at DESY (Hamburg, Germany), delivers high brilliance XUV and soft X-ray FEL radiation to photon experiments. After a shutdown to connect the second undulator beamline FLASH2 to the FLASH linac, re-commissioning of FLASH started in autumn 2013. The year 2014 is dedicated to FLASH1 user experiments. The commissioning of the FLASH2 beamline takes place in 2014 in parallel to FLASH1 operation.
	Slides TUOCA02 [9.156 MB]
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TUPRO038	Beam Positioning Concept and Tolerance Considerations for BERLinPro	laser, emittance, linac, timing	1105
	B.C. Kuske, J. Rudolph HZB, Berlin, Germany
	Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association BERLinPro is an ERL project at Helmholtz-Zentrum Berlin, with the goal to illuminate the challenges and promises of a high brightness 100 mA superconducting RF gun in combination with a 50 MeV return loop and energy recovery [1, 2]. The precision of the beam position in a single turn machine might be relaxed compared to the demands in storage rings. Still, a trajectory correction concept has to be developed and the influence of trajectory offsets on the goal parameters, its dependence on fluctuating injection parameters or effects related to the low energy of 6.5-50 MeV have to be investigated. This paper covers the initial trajectory correction studies and first tolerance scenarios of BERLinPro using the projected hardware concept.
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TUPME043	Temporal Electron-bunch Shaping from a Photoinjector for Advanced Accelerator Applications	space-charge, laser, wakefield, acceleration	1454
	F. Lemery, P. Piot Northern Illinois University, DeKalb, Illinois, USA P. Piot Fermilab, Batavia, Illinois, USA
	Advanced-accelerator applications often require the production of bunches with shaped temporal distributions. An example of sought-after shape is a linearly-ramped current profile that can be improve the transformer ratio in beam-driven acceleration, or produce energy-modulated pulse for, e.g., the subsequent generation of THz radiation. Typically, such a shaping is achieved by manipulating ultra-relativistic electron bunches. In this contribution we discuss the possibility of shaping the bunch via photoemission and demonstrate using particle-in-cell simulations the production of MeV electron bunches with quasi-ramped current profile.
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TUPME058	The Argonne Wakefield Accelerator (AWA): Commissioning and Operation	wakefield, electron, 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.
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TUPRI015	Transverse Emittance Compensation for the Rossendorf SRF Gun II	solenoid, SRF, cavity, electron	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.
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TUPRI077	Stabilization of Mid-infrared FEL by Feedback Controls	FEL, feedback, electron, klystron	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.
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TUPRI104	A Beam Arrival Time Cavity for REGAE at DESY	cavity, electron, coupling, 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.
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TUPRI113	Integration of the Timing System for TPS	timing, operation, injection, booster	1833
	C.Y. Wu, J. Chen, Y.-S. Cheng, K.T. Hsu, K.H. Hu, C.S. Huang, D. Lee, C.Y. Liao NSRRC, Hsinchu, Taiwan
	Timing system for the Taiwan Photon Source (TPS) were setup and ready for accelerator system commissioning. Event based timing system was chosen to satisfy various requirements for the machine and experiments. The system consist of event generator and multiple event receivers which installed local control nodes. The system is ready in the first quarter of 2014. Performance and functionality are investigated systematically. Parameters like delay, skew, latency, drift due to ambient temperature variation, etc. will be addressed. This report wills summary progress of TPS timing system before system delivery for accelerator commissioning.
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WEPRO003	Construction of a Laser Compton Scattered Photon Source at cERL	photon, laser, electron, cavity	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.
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WEPRO007	Nanometer Scale Coherent Current Modulation via a Nanotip Cathode Array and Emittance Exchange	electron, emittance, cavity, 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”.
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WEPRO018	Theoretical Maximum Current of the NSLS-II Linac	linac, simulation, beam-loading, cavity	1980
	R.P. Fliller, F. Gao, G.M. Wang BNL, Upton, Long Island, New York, USA
	Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. An analysis of the maximum available NSLS-II linac current was performed as part of the preparation for NSLS-II Booster commissioning. The analysis was necessary in order to establish the maximum beam current available from the linac and the maximum current that would be available to the booster accelerator. In this paper we discuss the assumptions that were used in determining the maximum linac current, the model of the linac and comparison to operational conditions.
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WEPRO019	Comparison of the NSLS-II Linac Model to Measurements	linac, cathode, emittance, simulation	1983
	R.P. Fliller BNL, Upton, Long Island, New York, USA
	Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy The NSLS-II linac and associated transport lines were successfully installed and commissioned in the spring of 2012. Various beam measurements were performed to ensure that the linac met specifications and would be a suitable injector for the NSLS-II booster. In this paper we discuss the outcomes of these measurements and compare them to the model of the NSLS-II linac.
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WEPRO052	The ThomX Project Status	laser, cavity, framework, synchrotron	2062
	A. Variola, D. Auguste, A. Blin, J. Bonis, S. Bouaziz, C. Bruni, K. Cassou, I. Chaikovska, S. Chancé, V. Chaumat, R. Chiche, P. Cornebise, O. Dalifard, N. Delerue, T. Demma, I.V. Drebot, K. Dupraz, N. El Kamchi, M. El Khaldi, P. Gauron, A. Gonnin, E. Guerard, J. Haissinski, M. Jacquet, D. Jehanno, M. Jouvin, E. Jules, F. Labaye, M. Lacroix, M. Langlet, D. Le Guidec, P. Lepercq, R. Marie, J.C. Marrucho, A. Martens, B. Mercier, E. Mistretta, H. Monard, Y. Peinaud, A. Pérus, B. Pieyre, E. Plaige, C. Prevost, T. Roulet, R. Roux, V. Soskov, A. Stocchi, C. Vallerand, A. Vermes, F. Wicek, Y. Yan, J.F. Zhang, Z.F. Zomer LAL, Orsay, France P. Alexandre, C. Benabderrahmane, F. Bouvet, L. Cassinari, M.-E. Couprie, P. Deblay, Y. Dietrich, M. Diop, M.E. El Ajjouri, M.P. Gacoin, C. Herbeaux, N. Hubert, M. Labat, P. Lebasque, A. Lestrade, R. Lopes, A. Loulergue, P. Marchand, F. Marteau, D. Muller, A. Nadji, R. Nagaoka, J.-P. Pollina, F. Ribeiro, M. Ros, R. Sreedharan SOLEIL, Gif-sur-Yvette, France A. Bravin, G. Le Duc, J. Susini ESRF, Grenoble, France C. Bruyère, A. Cobessi, W. Del Net, J.L. Hazemann, J.L. Hodeau, P. Jeantet, J. Lacipière, O. Proux Institut NEEL, Grenoble, France E. Cormier, J. Lhermite CELIA, Talence, France L. De Viguerie, H. Rousselière, P. Walter LAMS, Universite Pierre et Marie Curie, Ivry Sur Seine, France H. Elleaume, F. Esteve INSERM, Grenoble Institut des Neurosciences, La Tronche, France J.M. Horodinsky, N. Pauwels, P. Robert CNRS (IRSD), Orsay, France S. Sierra TED, Velizy, France
	Funding: Work supported by the French Agence Nationale de la Recherche as part of the program EQUIPEX under reference ANR-10-EQPX-51, the Ile de France region, CNRS-IN2P3 and Université Paris Sud XI A collaboration of seven research institutes and an industry has been set up for the ThomX project, a compact Compton Backscattering Source (CBS) based in Orsay – France. After a period of study and definition of the machine performances a complete description of all the systems has been provided. The infrastructures work is started and the main systems are in the call for tender phase. In this paper we will illustrate the definitive machine parameters and components characteristics. We will also update the results of the different ongoing R&D on optical resonators, fast power supplies for the injection kickers and on the electron gun.
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WEPRO090	Status of KAERI 6 MeV 9.3 GHz X-Band Electron Linac for Cancer Treatment System	linac, electron, cavity, 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.
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WEPRO103	Femtosecond Time-resolved Transmission Electron Microscopy using an RF Gun	electron, 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.
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WEPRO108	Electron Diffraction on VELA at Daresbury	electron, 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.
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WEPME005	Enhanced Field Emission and Emitter Activation on Flat Dry-ice Cleaned Cu Samples	site, electron, vacuum, factory	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
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WEPME009	Principles for Design of High Power Pulsed Microwave Devices and Devices with Low Operating Voltage for Accelerators	klystron, electron, 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".
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WEPME018	CERN Vacuum System Activities during the Long Shutdown 1: The LHC’s injector chain.	vacuum, linac, ion, operation	2291
	J.A. Ferreira Somoza, P. Chiggiato CERN, Geneva, Switzerland
	During the long shutdown 1 (LS1), several maintenance, consolidation and upgrade activities have been carried out in LHC’s injector chain. Each machine has specific vacuum requirements and different history, which determine the present status of the vacuum components, their maintenance and consolidation needs. The present work presents the priorities agreed at the beginning of the LS1 period and their implementation. Of particular relevance are the interventions in radioactive controlled areas where several leaks due to stress corrosions stopped the operations in the past years. The strategy to reduce the collective dose is presented, in particular the use of remote controlled robots. An important part of the work performed during this period involves supporting other teams (acceptance tests, new equipment installation, etc.). Finally, as a result of the LS1 experience, a medium to long term strategy is depicted, focusing on the preparation of the next shutdown (LS2) and the integration of LINAC4 in the injector chain during the same period.
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WEPME025	Design and Performance of Ultimate Vacuum System for the AREAL Test Facility	vacuum, cathode, dipole, electron	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.
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WEPME032	Detailed Investigation of the Low Energy Secondary Electron Yield of Technical Cu and its Relevance for LHC	electron, 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.
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WEPME057	The Secondary Electron Yield from Transition Metals	electron, vacuum, 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.
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WEPME060	Yb DOPED HIGH-ENERGY UV ULTRAFAST LASER FOR AREAL FACILITY	laser, electron, 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.
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WEPME061	Ytterbium Fiber and Disk Laser of RF Gun for SuperKEKB	laser, cavity, background, emittance	2415
	X. Zhou, T. Natsui, Y. Ogawa, M. Yoshida KEK, Ibaraki, Japan
	For SuperKEKB project, the electron beams with a charge of 5 nC and a normalized emittance of 10 μm are expected to be generated in the photocathode RF gun at the injector linac. An ytterbium (Yb)-doped laser system with a center wavelength of 259 nm and a pulse width of 30 ps is employed to obtain high peak energy pulses. Although, the pulse repetition of 25 Hz with double-bunch is required, more than 5 nC electron with single-bunch has so far been generated in the 2 Hz.
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WEPME065	European XFEL RF Gun Commissioning and LLRF Linac Installation	LLRF, linac, klystron, cryomodule	2427
	J. Branlard, G. Ayvazyan, V. Ayvazyan, L. Butkowski, M.K. Grecki, M. Hoffmann, F. Ludwig, U. Mavrič, S. Pfeiffer, H. Schlarb, Ch. Schmidt, H.C. Weddig, B.Y. Yang DESY, Hamburg, Germany S. Bou Habib, K. Czuba, M. Grzegrzółka, E. Janas, J. Piekarski, I. Rutkowski, R. Rybaniec, D. Sikora, L.Z. Zembala, M. Żukociński Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland W. Cichalewski, D.R. Makowski, A. Mielczarek, P. Perek, A. Piotrowski, T. Pożniak TUL-DMCS, Łódź, Poland S. Korolczuk, I.M. Kudla, J. Szewiński NCBJ, Świerk/Otwock, Poland K. Oliwa, W. Wierba IFJ-PAN, Kraków, Poland
	The European x-ray free electron laser (XFEL) is based on a 17.5 GeV super conducting pulsed linac and is scheduled to deliver its first beam in 2016. The first component of its accelerator chain, the RF gun, was installed in fall of 2013 and its commissioning is underway. This contribution gives an update on the low level radio frequency (LLRF) system development and installation for the XFEL. In particular, the installation, performance and conditioning results of the RF gun are presented. The subsequent steps toward LLRF components mass-production, testing and installation for the XFEL linac are also explained.
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WEPME066	High Speed Digitial LLRF Feedbacks for Normal Conducting Cavity Operation	LLRF, cavity, operation, klystron	2430
	M. Hoffmann, L. Butkowski, H. Schlarb, Ch. Schmidt DESY, Hamburg, Germany W. Köhler DESY Zeuthen, Zeuthen, Germany A. Piotrowski TUL-DMCS, Łódź, Poland I. Rutkowski, R. Rybaniec Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
	In the first half of the year 2014, the MTCA.4 based LLRF control system will be installed at several facilities (FLASH RF Gun, REGAE, PITZ, FLUTE/KIT). First tests during the last year show promising results in optimizing the system for high speed digital llrf feedbacks (reducing system latency, increase internal controller processing speed). In this contribution we will present further improvements in latency and performance optimization of the system, results and gained experience from the commisioning of the system at the metioned facilities.
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WEPRI018	Status of the Fabrication of the XFEL 3.9 GHz Cavity Series	cavity, status, linac, vacuum	2512
	C. Maiano, M. Bertucci, A. Bosotti, J.F. Chen, P. Michelato, L. Monaco, M. Moretti, C. Pagani, R. Paparella, P. Pierini, D. Sertore INFN/LASA, Segrate (MI), Italy
	The third harmonic system at 3.9 GHz of the European XFEL (E-XFEL) injector section will linearize the bunch RF curvature, induced by first accelerating module, before the first compression stage and it is a joint INFN and DESY contribution to the project. This paper presents the status of the fabrication of the 3.9 GHz cavity series in view of the XFEL injector commissioning in 2015.
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WEPRI025	Studies of Fabrication Procedure of 9-cell SRF Cavity for ILC Mass-production at KEK.	cavity, HOM, electron, 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.
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WEPRI058	Commissioning Status of the Advanced Superconducting Test Accelerator at Fermilab	laser, cryomodule, cavity, cathode	2615
	J. Ruan, R. Andrews, C.M. Baffes, D.R. Broemmelsiek, K. Carlson, B. Chase, M.D. Church, D.J. Crawford, E. Cullerton, J.S. Diamond, N. Eddy, D.R. Edstrom, E.R. Harms, A. Hocker, A.S. Johnson, A.L. Klebaner, M.J. Kucera, J.R. Leibfritz, A.H. Lumpkin, J.N. Makara, S. Nagaitsev, O.A. Nezhevenko, D.J. Nicklaus, L.E. Nobrega, P.S. Prieto, J. Reid, J.K. Santucci, G. Stancari, D. Sun, M. Wendt, S.J. Wesseln Fermilab, Batavia, Illinois, USA P. Piot Northern Illinois University, DeKalb, 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) is under construction at Fermilab. This accelerator will consist of a photo-electron gun, injector, ILC-type cryomodules, and multiple downstream beam-lines. Its purpose is to be a user-based facility for Advanced Accelerator R&D. . Following the successful commissioning of the photoinjector gun, a Tesla style 8-cavity cryomodule and a high gradient capture cavity have been cooled down to 2 K and powered commissioning and performance characterization has begun. We will report on the commissioning status and near-term future plans for the facility.
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WEPRI059	Assembly and Installation of the UV Laser Delivery and Diagnostic Platform and the Photocathode Imaging System for the ASTA Front-end	laser, optics, diagnostics, vacuum	2618
	D.J. Crawford, R. Andrews, T.W. Hamerla, J. Ruan, J.K. Santucci, 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. The Advanced Superconducting Test Accelerator (ASTA) is in the early stage of commissioning. 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 area for measuring the characteristics of the photoelectron beam. We report on the design, construction, and early experience of the ultra-violet (UV) Laser Delivery and Diagnostic Platform and the Photocathode Imaging System.
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THPRO025	Conceptual Design of a X-FEL Facility using CLIC X-band Accelerating Structure	linac, FEL, klystron, simulation	2914
	A.A. Aksoy, O. Yavaş Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey D. Angal-Kalinin, J.A. Clarke Cockcroft Institute, Warrington, Cheshire, United Kingdom M.J. Boland SLSA, Clayton, Australia G. D'Auria, S. Di Mitri, C. Serpico Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy M. Doğan Dogus University, Istanbul, Turkey T.J.C. Ekelöf, R.J.M.Y. Ruber, V.G. Ziemann Uppsala University, Uppsala, Sweden W. Fang, Q. Gu SINAP, Shanghai, People's Republic of China A. Latina, D. Schulte, S. Stapnes, I. Syratchev, W. Wuensch CERN, Geneva, Switzerland Z. Nergiz Nigde University, Nigde University Science & Art Faculty, Nigde, Turkey
	Within last decade a linear accelerating structure with an average loaded gradient of 100 MV/m at 12 GHz has been demonstrated in the CLIC study. Recently, it has been proposed to use the CLIC structure to drive an FEL linac. In contrast to CLIC the linac would be powered by klystrons not by a drive beam. The main advantage of this proposal is achieving the required energies in a very short distance, thus the facility would be rather compact. In this study, we present the conceptual design parameters of a facility which could generate laser photon pulses covering the range of 1-75 Angstrom. Shorter wavelengths could also be reached with slightly increasing the energy.
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THPRO028	Bunch Compressor Design for CLIC Drive Beam	linac, cathode, linear-collider, collider	2924
	A.A. Aksoy Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey J. Esberg, D. Schulte CERN, Geneva, Switzerland
	The drive-beam linac which is required for generation RF power at Compact Linear Collider (CLIC) has to accelerate an electron beam with 8.4 nC per bunch up to 2.4 GeV in almost fully loaded structures. The required beam stability in both transverse and longitudinal directions are of concern for such a high bunch charge. We present different bunch compressor designs for the Drive Beam and compare their performance including the effects beam energy and phase jitters.
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THPRO029	A Front End for the CLARA FEL Test Facility at Daresbury Laboratory	linac, dipole, bunching, emittance	2927
	P.H. Williams, D. Angal-Kalinin, J.A. Clarke, B.D. Fell, J.K. Jones, J.W. McKenzie, B.L. Militsyn STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	The next step towards the full CLARA facility is installation of the CLARA front end to comprise a 2m S-band linac section after the photoinjector gun. This will be suitable for both the velocity bunching and standard booster modes of CLARA. An S-bend will also be installed to deflect the beam into the current VELA line, enabling delivery of higher energy beams to two existing user areas. The current photoinjector beam diagnostics section can then be used to test a High Repetition Rate electron gun currently under development. We describe the proposed CLARA front end design. We define two beam dynamics working points for CLARA, one working point for sending beam from the CLARA Front End to VELA, and one working point to feed an interim user station prior to CLARA full construction in the straight-on position.
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THPRO031	Short Pulses THz FEL for the Oxford Accelerator Science Laboratory	FEL, radiation, cavity, undulator	2934
	T. Chanwattana, R. Bartolini, A. Seryi JAI, Oxford, United Kingdom R. Bartolini DLS, Oxfordshire, United Kingdom E. Tsesmelis CERN, Geneva, Switzerland
	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 short pulse THz FEL based on a conventional RF accelerator driven by a RF photocathode gun is being investigated. This report presents the concept of the facility, the accelerator physics and FEL studies and engineering integration in the University physics department.
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THPRO042	Field Emission Studies of Heat Treated Mo Substrates	SRF, cathode, electron, 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.
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THPRO044	Report on Gun Conditioning Activities at PITZ in 2013	cathode, cavity, vacuum, FEL	2962
	M. Otevřel, P. Boonpornprasert, J.D. Good, M. Groß, I.I. Isaev, D.K. Kalantaryan, M. Khojoyan, G. Kourkafas, M. Krasilnikov, D. Malyutin, D. Melkumyan, T. Rublack, F. Stephan, G. Vashchenko DESY Zeuthen, Zeuthen, Germany G. Asova INRNE, Sofia, Bulgaria P. Boonpornprasert, S. Rimjaem Chiang Mai University, Chiang Mai, Thailand F. Brinker, K. Flöttmann, S. Lederer, B. Marchetti, S. Schreiber DESY, Hamburg, Germany Ye. Ivanisenko PSI, Villigen PSI, Switzerland M.A. Nozdrin JINR, Dubna, Moscow Region, Russia G. Pathak Uni HH, Hamburg, Germany D. Richter BESSY GmbH, Berlin, Germany
	Recently three RF guns were prepared at the Photo Injector Test Facility at DESY, location Zeuthen (PITZ) for their subsequent operation at FLASH and the European XFEL. The gun 3.1 is a previous cavity design and is currently installed and operated at FLASH, the other two guns 4.3 and 4.4 were of the current cavity design and are dedicated to serve for the start-up of the European XFEL photo-injector. All three cavities had been dry-ice-cleaned prior their conditioning and hence showed low dark current levels. The lowest dark current level – as low as 60μA at 65MV/m field amplitude – has been observed for the gun 3.1. This paper reports in details about the conditioning process of the most recent gun 4.4. It informs about experience gained at PITZ during establishing of the RF conditioning procedure and provides a comparison with the other gun cavities in terms of the dark currents. It also summarizes the major setup upgrades, which have affected the conditioning processes of the cavities.
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THPRO045	Design and Construction of a Thermionic Cathode RF Electron Gun for Iranian Light Source Facility	electron, 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.
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THPRO048	Emittance and Bunch Length Measurement of the Electron Beams from the NSRRC Photocathode Gun	emittance, electron, 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.
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THPRO051	Cavity Design for a S-Band Photoinjector RF Gun with 400 Hz Repetition Rate	cavity, FEL, cathode, emittance	2983
	J.W. McKenzie, L.S. Cowie, P. Goudket, B.L. Militsyn STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom G. Burt Cockcroft Institute, Lancaster University, Lancaster, United Kingdom T.J. Jones STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom V.V. Paramonov RAS/INR, Moscow, Russia
	As part of the design of CLARA (Compact Linear Accelerator for Research and Applications), the proposed UK FEL test facility at Daresbury Laboratory, a high repetition rate S-band photoinjector RF gun is being developed. This gun will be able to operate at up to 400 Hz repetition rate in single bunch mode. We present the initial cavity design including its optimisation for the beam dynamics of CLARA. We also present the initial cooling design for the cavity which will enable the high repetition rates to be achieved.
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THPRO052	Beam Physics Commissioning of VELA at Daresbury Laboratory	emittance, laser, diagnostics, quadrupole	2986
	B.L. Militsyn, D. Angal-Kalinin, A.D. Brynes, F. Jackson, J.K. Jones, A. Kalinin, J.W. McKenzie, B.D. Muratori, T.C.Q. Noakes, D.J. Scott, E.W. Snedden, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom M.D. Roper STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
	A user facility VELA (Versatile Electron Linear Accelerator) based on an RF photoinjector has been commissioned at Daresbury Laboratory in April 2013, providing beam to first users in September 2013. Machine study runs in 2013-2014 have concentrated on characterisation of main beam parameters like bunch charge, its momentum, beam emittance and dependence of these parameters on the launching RF phase. Major efforts have been also concentrated on investigation of the dark current from the gun and its dependence on the RF amplitude. Significant time has been dedicated to investigation of relative stability of LLRF and drive laser having significant impact on the overall machine stability. We present here the results of these studies.
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THPRO054	LLNL X-band Test Station Commissioning and X-ray Status	laser, vacuum, alignment, emittance	2992
	R.A. Marsh, G.G. Anderson, S.G. Anderson, C.P.J. Barty, M. Betts, S.E. Fisher, D.J. Gibson, F.V. Hartemann, S.S.Q. Wu LLNL, Livermore, California, USA
	Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 An X-band test station is being commissioned at LLNL to support inverse Compton-scattering x-ray and gamma-ray source development. The X-band test station has been built and this presentation will focus on its current status and the generation of first electron beam. Special focus will be placed on the high gradient conditioning of the T53 traveling wave accelerator and Mark 1 X-band standing wave RF gun. Design and installation of the inverse-Compton scattering interaction region, future upgrade paths and configuration for a variety of x-ray and gamma-ray applications will be discussed along with the status of theory and modeling efforts.
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THPRO074	Characterization of the Longitudinal Wakefields in the MAX IV Linac	linac, wakefield, simulation, FEL	3050
	O. Karlberg, F. Curbis, S. Thorin, S. Werin MAX-lab, Lund, Sweden
	In the second part of 2014, the 3GeV linac at the MAX IV laboratory will enter its commissioning stage. Equipped with two guns, the linac will act as a full energy injector for the two storage rings and at the same time provide high brightness pulses to a Short Pulse Facility (SPF). Compression in the linac is done in two double achromats with fixed R56 that relies upon the RF phase introduced energy chirp, which in this case is strongly enhanced by the longitudinal wakefields. Since the longitudinal wakefields plays a major role in the compression and bunch shaping they need to be carefully investigated during the commissioning. In this proceeding we will discuss a measurement technique that will be used during commissioning to characterize the longitudinal wakefields and their precise effects on e.g. the bunch shape and the energy spread. Predictions obtained from particle tracking will be presented.
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THPRO093	Low Emittance Electron Beam Transportation in Compact ERL Injector	cathode, focusing, laser, solenoid	3104
	T. Miyajima, K. Harada, Y. Honda, T. Kume, S. Nagahashi, N. Nakamura, T. Obina, S. Sakanaka, M. Shimada, R. Takai, T. Uchiyama, A. Ueda, M. Yamamoto KEK, Ibaraki, Japan R. Hajima, R. Nagai, N. Nishimori JAEA, Ibaraki-ken, Japan J.G. Hwang Kyungpook National University, Daegu, Republic of Korea
	For future light source based on Energy Recovery Linac (ERL), an injector, which consists of a photocathode DC gun and superconducting RF cavities, is a key part to generate a low emittance, short pulse and high bunch charge electron beam. In compact ERL (cERL) which is a test accelerator to develop key technologies for ERL, the generation of low emittance electron beam with 0.1 mm mrad normalized emittance and 390 keV beam energy from the photocathode DC gun, and the acceleration to 5.6 MeV by superconducting cavity, were demonstrated in the first beam commissioning. To keep the high quality in the beam transportation, understanding the beam optics, which is affected by not only the focusing effects due to the gun, solenoid magnets and RF cavities but also space charge effect, is required. In this presentation, we will show that how to measure and correct the focusing effect by experimental method. Using this method, we succeeded in correcting the analytical model to give the good agreement with the measured gun focusing for low charge beam. And, we will show the space charge effect for high bunch charge beam.
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THPRO127	Current Status of TARLA Control System	controls, EPICS, LabView, operation	3192
	E. Kazancı, A.A. Aksoy, A. Aydin, C. Kaya, B. Tonga, O. Yavaş Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey S. Özkorucuklu Istanbul University, Istanbul, Turkey
	Funding: This study was funded by Ministry of Development of Turkey by grant id DPT2006K-120470 Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) is a Free Electron Laser (FEL) facility designed to generate Free Electron Laser (FEL) in 3-250 um wavelength range, based on four 9-cell Super Conducting (SC) cavities with 10MeV/m gradient each. TARLA electron gun has been in operation since 2012. Control system studies with EPICS are being run as test stand control and permanent system and each are running as individual projects while test stand control is in stable revision. The aim of the system design is to create a fast and reliable control system which is easy to operate and extensible for future upgrades/improvements. Now, the development and implementation of control system is ongoing in a parallel manner with the rest of the accelerator as well as the architectural design, In this study, the permanent and the test stand control systems of TARLA will be discussed. On behalf of TARLA Team
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO127
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THPME079	Beam Diagnostics and Control for the AREAL RF Photogun Linac	controls, diagnostics, linac, electron	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.
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Paper

Title

Other Keywords

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MOZB01

Superconducting RF Guns: Emerging Technology for Future Accelerators

cathode, SRF, cavity, laser

4085

J. Teichert
HZDR, Dresden, Germany

This talk should give an overview of Superconducting photo injectors (SRF guns) and focus on the present status of SRF gun development, the technical requirements and the critical issues like cavity design, photocathode integration, and emittance compensation methods.

Slides MOZB01 [22.198 MB]

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MOPRO001

Upgrade Status of Injector LINAC for SuperKEKB

positron, electron, linac, emittance

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.

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MOPRO013

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

electron, ion, cavity, 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.

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MOPRO066

Status of FLUTE

laser, electron, 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.

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MOPRO091

Fundamental Limits of Velocity Bunching of High-brightness Electron Beams

bunching, electron, emittance, cavity

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.

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MOPRO106

Status of the HZB ERL Prototype BERLinPro

linac, cavity, SRF, booster

340

M. Abo-Bakr, W. Anders, R. Barday, K.B. Bürkmann-Gehrlein, A. Burrill, V. Dürr, A. Jankowiak, C. Kalus, T. Kamps, G. Klemz, J. Knobloch, J. Kolbe, O. Kugeler, B.C. Kuske, A.N. Matveenko, A. Meseck, A. Neumann, K. Ott, E. Panofski, D. Pflückhahn, J. Rahn, J. Rudolph, M. Schmeißer, S.G. Schubert, O. Schüler, J. Völker, S. Wesch
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 Prototype BERLinPro is to be constructed at the Helmholtz Zentrum site in Berlin. The aim of the project is to expand the required accelerator physics and technology knowledge mandatory for the generation of a high current (100 mA), high brilliance (norm. emittance below 1 mm mrad) cw electron beam. Since the funding decision in October 2010 the project has entered a phase of detailed planning. Hardware specifications have been defined and various components have been ordered. Furthermore, extensive tests of principal superconducting accelerator components successfully demonstrated the envisaged hardware performance. A summary of the most recent activities together with the details of the project timeline for the coming years are given in this paper.

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MOPRO107

Multi-turn ERL-based Synchrotron Light Facility: Injector Design

emittance, linac, brilliance, booster

343

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

Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association VH NG 636 and HRJRG-214
Multi-turn energy recovery linac based light sources are candidates for the future 4th generation synchrotron light sources. Using the superconducting linac technology, the Femto-Science-Factory (FSF) will provide its users with ultra-bright photon beams of angstrom wavelength at 6 GeV final beam energy. The FSF is intended to be a multi-user facility and offers a variety of operation modes. An overview of the machine layout and magnetic optics design of the installation will be given in this paper with the focus on high brightness injector design.

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MOPRO112

Energy Recovering for Linac RF Injectors

cavity, SRF, HOM, linac

356

V. Volkov, Ya.V. Getmanov, O.A. Shevchenko, N. Vinokurov
BINP SB RAS, Novosibirsk, Russia
A.N. Matveenko
HZB, Berlin, Germany

The article presents a new design of a CW RF high average current superconducting injector cavity. This design allows recovering energy in the injector, improving beam parameters and energy efficiency, reducing injector size, cost, and avoiding high average power coupler problem.

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MOPME008

3d Full Electromagnetic Beam Dynamics Simulations of the Pitz Photoinjector

simulation, laser, cathode, emittance

391

Y. Chen, E. Gjonaj, W.F.O. Müller, T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: work supported by DESY, Hamburg and Zeuthen sites
The electromagnetic (EM) simulation software CST STUDIO SUITE® * has been applied to investigate the beam dynamics for the electron gun of the Photo Injector Test facility at DESY, Zeuthen site (PITZ). A series of 3D beam dynamics simulations are performed to study the bunch injection process at PITZ with the objective of clarifying the discrepancies between measurements and simulations. Multiple comparisons are presented for the transverse emittance and the total emitted charge between the measurement data and simulation results using CST STUDIO SUITE®and Astra **.
* Computer Simulation Technology AG, website: http://www.cst.com/
** K. Floettmann A Space Charge Tracking Algorithm, user manual (version 3), 2011

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MOPME033

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

electron, simulation, collider, 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.

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MOPME067

Kicker Development at the ELBE Facility

kicker, positron, SRF, electron

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.

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MOPRI017

Status of AREAL RF Photogun Test Facility

electron, 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.

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MOPRI020

Introducing GunLab – A Compact Test Facility for SRF Photoinjectors

electron, 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.

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MOPRI023

Simulation of the ELBE SRF Gun II

simulation, emittance, SRF, laser

636

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

Funding: EuCARD, contract number 227579 German Federal Ministry of Education and Research grant 05 ES4BR1/8 LA³NET, Grant Agreement Number GA-ITN-2011-289191
By combining the code of ASTRA and elegant in a user-friendly interface, a simulation tool is developed for the ELBE SRF Gun II. The photoelectric emission and first acceleration to several MeV in the gun cavity are simulated by ASTRA with a 1D Model, where the space charge effect is considered. The dependence of the beam quality on key parameters is studied, and a compromised optimization for a 77 pC beam is used for further elegant simulation of the beam transport through a dogleg and ELBE Linacs. Proper settings of the magnets and RF phases are the main targets of improving the beam quality. Up to now the best simulation result is an electron bunch with the energy of 47 MeV, energy spread of 66 keV, bunch length of 0.35 ps and transverse emittance of 1.9 μm and 2.7 μm in the two perpendicular directions.

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MOPRI024

NEA-GaAs (Cs, O) Photocathodes for the ELBE SRF Gun

vacuum, SRF, cathode, laser

639

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

Funding: supported by the European Community under the FP7 programme (EuCARD-2, contract number 312453, and LA3NET, contract number 289191), and by the BMBF grant 05K12CR1.
At HZDR a preparation chamber for NEA-GaAs (Cs, O) has been built and commissioned. GaAs is the next photocathode material for the ELBE SRF gun, which has been successfully operated with Cs2Te layer in last years. GaAs At HZDR a preparation chamber for NEA-GaAs (Cs, O) has been built and tested. GaAs is the next photocathode material for the ELBE SRF gun, which has been successfully operated with Cs2Te photocathode in last years. GaAs photocathodes are advantageous because of their high quantum efficiency (QE) with visible light and the extensive experiences of their use in DC guns. Furthermore, GaAs photocathodes provide the possibility to realize a polarized SRF gun in the future. In this presentation we will introduce the new preparation system and the first results of the GaAs tests. The new transfer system under construction will be also presented.

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MOPRI025

Recent Improvement of Cs2Te Photocathodes at HZDR

cathode, vacuum, SRF, cavity

642

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

Funding: Work supported by the European Community-Research Infrastructure Activity (EuCARD, contract number 227579), and the support of the German Federal Ministry of Education and Research grant 05 ES4BR1/8.
The SRF gun has been successfully operated for the radiation source ELBE at HZDR. To achieve higher current and lower beam emittance, a new niobium cavity with superconducting solenoid and a new 13 MHz laser have been recently developed. For this reason, better photocathodes with high quantum efficiency are urgently in demand. In this work we improve the present Cs2Te preparation system for cleaner environment and more precise stoichiometric control than before. A new mask is designed to prevent cesium pollution of the cathode body. Instead of Kapton only alumina ceramics are used for isolation, and the cathode plugs are degassed at higher temperature. New evaporators are installed and tested to obtain an accurate deposition rate. Furthermore, the cathode transfer system is thoroughly cleaned for a better vacuum condition.

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MOPRI027

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

electron, 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.

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MOPRI028

Different Countermeasures of Electron Amplification in the Photocathode Unit

cathode, electron, SRF, 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.

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MOPRI030

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

cavity, simulation, electron, 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.

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MOPRI033

Quasi-traveling Wave Side Couple RF Gun Commissioning for SuperKEKB

cavity, emittance, cathode, coupling

667

T. Natsui, Y. Ogawa, M. Yoshida, X. Zhou
KEK, Ibaraki, Japan

We are developing a new RF gun for SuperKEKB. High-charge low-emittance electron and positron beams are required for SuperKEKB. We will generate 7.0 GeV electron beam at 5 nC 20 mm-mrad by J-linac. In this linac, a photo cathode S-band RF gun will be used as the electron beam source. For this reason, we are developing an advanced RF gun. New RF gun which has two side coupled standing wave field is developed. We call it quasi traveling wave side couple RF gun. This gun has a strong focusing field at the cathode and the acceleration field distribution also has a focusing effect. Beam commissioning has been started with the new RF gun. I will report the result of beam commissioning.

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MOPRI036

Pulse Radiolysis Using Terahertz Probe Pulses

electron, laser, radiation, 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).

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MOPRI037

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

laser, electron, cathode, 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.

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MOPRI039

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

electron, 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.

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MOPRI040

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

electron, 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.

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MOPRI041

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

cathode, electron, Windows, 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".

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MOPRI043

Study of a C-band Standing-wave Gun for the SwissFEL Injector

cathode, solenoid, coupling, emittance

698

M. Schaer, S. Bettoni, A. Citterio, P. Craievich, M. Negrazus, L. Stingelin, R. Zennaro
PSI, Villigen PSI, Switzerland

The baseline design of the SwissFEL injector foresees the "PSI Gun 1", a 2.6-cell RF photo-cathode gun operating at S-band frequency, as the electron source. In this paper a new design is presented where a 5.6-cell C-band gun could replace the PSI Gun 1 with no impact on the rest of the injector setup. A conservative maximum gradient of 135 MV/m at the cathode is assumed which drives the electron beam faster into the relativistic regime and therefore allows to tolerate larger charge densities. The presented solution also foresees a coaxial RF coupling from the cathode side in order to place the gun solenoid as near to the photo-cathode as possible, improving the emittance compensation. Astra simulations showed that the transverse beam brightness can be doubled before the first bunch compressor preserving the low transverse emittance value as compared to the current design for the S-band injector configuration of SwissFEL.

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MOPRI044

Feasibility Study of an Ultrafast Electron Diffraction System in NSRRC

electron, 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.

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MOPRI045

Beam Diagnostics E-GUN Test Stand at TARLA

electron, 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

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MOPRI047

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

ion, plasma, laser, electron

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.

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MOPRI053

High Repetition Rate Ultrafast Electron Diffraction at LBNL

electron, emittance, 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.

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MOPRI054

Status of the APEX Project at LBNL

cathode, cavity, FEL, linac

727

F. Sannibale, K.M. Baptiste, C.W. Cork, J.N. Corlett, S. De Santis, L.R. Doolittle, J.A. Doyle, D. Filippetto, G.L. Harris, G. Huang, H. Huang, R. Huang, T.D. Kramasz, S. Kwiatkowski, R.E. Lellinger, V. Moroz, W.E. Norum, C. F. Papadopoulos, G.J. Portmann, H.J. Qian, J.W. Staples, M. Vinco, S.P. Virostek, R.P. Wells, M.S. Zolotorev
LBNL, Berkeley, California, USA
R. Huang
USTC/NSRL, Hefei, Anhui, 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 Advanced Photo-injector EXperiment (APEX) at the Lawrence Berkeley National Laboratory (LBNL), consists in the development of an injector designed to demonstrate the capability of the VHF gun, a normal conducting 186 MHz RF gun operating in CW mode, to deliver the brightness required by X-ray FEL applications at MHz repetition rate. APEX is organized in 3 main phases where different aspects of the required performance are gradually demonstrated. The status and future plans for the project are presented.

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MOPRI055

APEX Present Experimental Results

cathode, electron, 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.

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MOPRI056

Design and Fabrication of a VHF - CW High Repetition Rate Electron Gun

cavity, cathode, vacuum, operation

733

R.P. Wells, B. Ghiorso, F. Sannibale, J.W. Staples
LBNL, Berkeley, California, USA
T.M. Huang
IHEP, 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
A high repetition rate, MHz, electron source is a key element in future FEL based light sources. The Advance Photo-injector Experiment (APEX) at Lawrence Berkeley National Laboratory (LBNL) consists of a high repetition rate 186 MHz (VHF-band) CW electron gun, 1 MHz UV laser source and the diagnostic components necessary to quantify the gun’s performance. The gun design is based on well established, conventional RF cavity design, with a couple notable exceptions. The basis for the selection of this technology, novel design features, fabrication techniques and measured cavity performance are presented.

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MOPRI059

Fabrication of Alkali Antimonide Photocathode for SRF Gun

cathode, laser, vacuum, SRF

742

E. Wang, S.A. Belomestnykh, I. Ben-Zvi, D. Kayran, G.T. McIntyre, T. Rao, J. Smedley, D. Weiss, W. Xu
BNL, Upton, Long Island, New York, USA
I. Ben-Zvi, M. Ruiz-Osés
Stony Brook University, Stony Brook, USA
X. Liang
SBU, Stony Brook, New York, USA
H.M. Xie
PKU, Beijing, People's Republic of China

Funding: * This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE and DOE grant
The first alkali antimonide photocathode was prepared and inserted into the BNL 704 MHz SRF gun. An excimer laser cleaning system was installed in a cathode deposition chamber and the cleaning technique developed previously was used in the first cathode preparation. We also demonstrated that oxidized cathode can be removed by exposing it to the same excimer laser. In this paper, we show the set up of the incorporated laser cleaning system and the QE enhancement of alkali antimony photocathode. The vacuum evolution at transport cart and QE measurement system are also discussed.

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MOPRI063

Alkali Antimonide Photocathodes in a Can

cathode, vacuum, insertion, controls

745

J. Smedley, K. Attenkofer, T. Rao, S.G. Schubert
BNL, Upton, Long Island, New York, USA
I. Ben-Zvi, X. Liang, E.M. Muller, M. Ruiz-Osés
Stony Brook University, Stony Brook, USA
J. DeFazio
PHOTONIS USA Pennsylvanis, Inc., Lancaster, Pennsylvania, USA
H.A. Padmore, J.J. Wong
LBNL, Berkeley, California, USA
J. Xie
ANL, Argonne, Illinois, USA

Funding: Work was supported by the US DOE, under Contracts DE-AC02-05CH11231, DE-AC02-98CH10886, KC0407-ALSJNT-I0013, DE-FG02-12ER41837 and DE-SC0005713. Use of CHESS is supported by NSF award DMR-0936384.
The next generation of x-ray light sources will need reliable, high quantum efficiency photocathodes. These cathodes will likely be from the alkali antimonide family, which currently holds the record for highest average current achieved from a photoinjector. In this work, we explore a new option for delivering these cathodes to a machine which requires them: use of sealed commercial vacuum tubes. Several sealed tubes have been introduced into a vacuum system and separated from their housing, exposing the active photocathode on a transport arm suitable for insertion into a photoinjector. The separation has been achieved without loss of QE. These cathodes are compared to those grown via traditional methods, both in terms of QE and in terms of crystalline structure, and found to be similar.

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MOPRI064

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

SRF, cathode, cavity, electron

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.

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MOPRI073

Status of the HESR Electron Cooler Test Set-up

electron, 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.

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MOPRI075

COSY 2 MeV Cooler: Design, Diagnostic and Commissioning

electron, controls, 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.

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TUOCA02

Status of the Free Electron Laser User Facility FLASH

FEL, flattop, laser, linac

938

M. Vogt, B. Faatz, J. Feldhaus, K. Honkavaara, S. Schreiber, R. Treusch
DESY, Hamburg, Germany

FLASH, the Free Electron Laser User Facility at DESY (Hamburg, Germany), delivers high brilliance XUV and soft X-ray FEL radiation to photon experiments. After a shutdown to connect the second undulator beamline FLASH2 to the FLASH linac, re-commissioning of FLASH started in autumn 2013. The year 2014 is dedicated to FLASH1 user experiments. The commissioning of the FLASH2 beamline takes place in 2014 in parallel to FLASH1 operation.

Slides TUOCA02 [9.156 MB]

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TUPRO038

Beam Positioning Concept and Tolerance Considerations for BERLinPro

laser, emittance, linac, timing

1105

B.C. Kuske, J. Rudolph
HZB, Berlin, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association
BERLinPro is an ERL project at Helmholtz-Zentrum Berlin, with the goal to illuminate the challenges and promises of a high brightness 100 mA superconducting RF gun in combination with a 50 MeV return loop and energy recovery [1, 2]. The precision of the beam position in a single turn machine might be relaxed compared to the demands in storage rings. Still, a trajectory correction concept has to be developed and the influence of trajectory offsets on the goal parameters, its dependence on fluctuating injection parameters or effects related to the low energy of 6.5-50 MeV have to be investigated. This paper covers the initial trajectory correction studies and first tolerance scenarios of BERLinPro using the projected hardware concept.

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TUPME043

Temporal Electron-bunch Shaping from a Photoinjector for Advanced Accelerator Applications

space-charge, laser, wakefield, acceleration

1454

F. Lemery, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
P. Piot
Fermilab, Batavia, Illinois, USA

Advanced-accelerator applications often require the production of bunches with shaped temporal distributions. An example of sought-after shape is a linearly-ramped current profile that can be improve the transformer ratio in beam-driven acceleration, or produce energy-modulated pulse for, e.g., the subsequent generation of THz radiation. Typically, such a shaping is achieved by manipulating ultra-relativistic electron bunches. In this contribution we discuss the possibility of shaping the bunch via photoemission and demonstrate using particle-in-cell simulations the production of MeV electron bunches with quasi-ramped current profile.

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TUPME058

The Argonne Wakefield Accelerator (AWA): Commissioning and Operation

wakefield, electron, 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.

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TUPRI015

Transverse Emittance Compensation for the Rossendorf SRF Gun II

solenoid, SRF, cavity, electron

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.

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TUPRI077

Stabilization of Mid-infrared FEL by Feedback Controls

FEL, feedback, electron, klystron

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.

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TUPRI104

A Beam Arrival Time Cavity for REGAE at DESY

cavity, electron, coupling, 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.

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TUPRI113

Integration of the Timing System for TPS

timing, operation, injection, booster

1833

C.Y. Wu, J. Chen, Y.-S. Cheng, K.T. Hsu, K.H. Hu, C.S. Huang, D. Lee, C.Y. Liao
NSRRC, Hsinchu, Taiwan

Timing system for the Taiwan Photon Source (TPS) were setup and ready for accelerator system commissioning. Event based timing system was chosen to satisfy various requirements for the machine and experiments. The system consist of event generator and multiple event receivers which installed local control nodes. The system is ready in the first quarter of 2014. Performance and functionality are investigated systematically. Parameters like delay, skew, latency, drift due to ambient temperature variation, etc. will be addressed. This report wills summary progress of TPS timing system before system delivery for accelerator commissioning.

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WEPRO003

Construction of a Laser Compton Scattered Photon Source at cERL

photon, laser, electron, cavity

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.

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WEPRO007

Nanometer Scale Coherent Current Modulation via a Nanotip Cathode Array and Emittance Exchange

electron, emittance, cavity, 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”.

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WEPRO018

Theoretical Maximum Current of the NSLS-II Linac

linac, simulation, beam-loading, cavity

1980

R.P. Fliller, F. Gao, G.M. Wang
BNL, Upton, Long Island, New York, USA

Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
An analysis of the maximum available NSLS-II linac current was performed as part of the preparation for NSLS-II Booster commissioning. The analysis was necessary in order to establish the maximum beam current available from the linac and the maximum current that would be available to the booster accelerator. In this paper we discuss the assumptions that were used in determining the maximum linac current, the model of the linac and comparison to operational conditions.

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WEPRO019

Comparison of the NSLS-II Linac Model to Measurements

linac, cathode, emittance, simulation

1983

R.P. Fliller
BNL, Upton, Long Island, New York, USA

Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
The NSLS-II linac and associated transport lines were successfully installed and commissioned in the spring of 2012. Various beam measurements were performed to ensure that the linac met specifications and would be a suitable injector for the NSLS-II booster. In this paper we discuss the outcomes of these measurements and compare them to the model of the NSLS-II linac.

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WEPRO052

The ThomX Project Status

laser, cavity, framework, synchrotron

2062

A. Variola, D. Auguste, A. Blin, J. Bonis, S. Bouaziz, C. Bruni, K. Cassou, I. Chaikovska, S. Chancé, V. Chaumat, R. Chiche, P. Cornebise, O. Dalifard, N. Delerue, T. Demma, I.V. Drebot, K. Dupraz, N. El Kamchi, M. El Khaldi, P. Gauron, A. Gonnin, E. Guerard, J. Haissinski, M. Jacquet, D. Jehanno, M. Jouvin, E. Jules, F. Labaye, M. Lacroix, M. Langlet, D. Le Guidec, P. Lepercq, R. Marie, J.C. Marrucho, A. Martens, B. Mercier, E. Mistretta, H. Monard, Y. Peinaud, A. Pérus, B. Pieyre, E. Plaige, C. Prevost, T. Roulet, R. Roux, V. Soskov, A. Stocchi, C. Vallerand, A. Vermes, F. Wicek, Y. Yan, J.F. Zhang, Z.F. Zomer
LAL, Orsay, France
P. Alexandre, C. Benabderrahmane, F. Bouvet, L. Cassinari, M.-E. Couprie, P. Deblay, Y. Dietrich, M. Diop, M.E. El Ajjouri, M.P. Gacoin, C. Herbeaux, N. Hubert, M. Labat, P. Lebasque, A. Lestrade, R. Lopes, A. Loulergue, P. Marchand, F. Marteau, D. Muller, A. Nadji, R. Nagaoka, J.-P. Pollina, F. Ribeiro, M. Ros, R. Sreedharan
SOLEIL, Gif-sur-Yvette, France
A. Bravin, G. Le Duc, J. Susini
ESRF, Grenoble, France
C. Bruyère, A. Cobessi, W. Del Net, J.L. Hazemann, J.L. Hodeau, P. Jeantet, J. Lacipière, O. Proux
Institut NEEL, Grenoble, France
E. Cormier, J. Lhermite
CELIA, Talence, France
L. De Viguerie, H. Rousselière, P. Walter
LAMS, Universite Pierre et Marie Curie, Ivry Sur Seine, France
H. Elleaume, F. Esteve
INSERM, Grenoble Institut des Neurosciences, La Tronche, France
J.M. Horodinsky, N. Pauwels, P. Robert
CNRS (IRSD), Orsay, France
S. Sierra
TED, Velizy, France

Funding: Work supported by the French Agence Nationale de la Recherche as part of the program EQUIPEX under reference ANR-10-EQPX-51, the Ile de France region, CNRS-IN2P3 and Université Paris Sud XI
A collaboration of seven research institutes and an industry has been set up for the ThomX project, a compact Compton Backscattering Source (CBS) based in Orsay – France. After a period of study and definition of the machine performances a complete description of all the systems has been provided. The infrastructures work is started and the main systems are in the call for tender phase. In this paper we will illustrate the definitive machine parameters and components characteristics. We will also update the results of the different ongoing R&D on optical resonators, fast power supplies for the injection kickers and on the electron gun.

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WEPRO090

Status of KAERI 6 MeV 9.3 GHz X-Band Electron Linac for Cancer Treatment System

linac, electron, cavity, 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.

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WEPRO103

Femtosecond Time-resolved Transmission Electron Microscopy using an RF Gun

electron, 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.

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WEPRO108

Electron Diffraction on VELA at Daresbury

electron, 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.

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WEPME005

Enhanced Field Emission and Emitter Activation on Flat Dry-ice Cleaned Cu Samples

site, electron, vacuum, factory

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

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WEPME009

Principles for Design of High Power Pulsed Microwave Devices and Devices with Low Operating Voltage for Accelerators

klystron, electron, 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".

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WEPME018

CERN Vacuum System Activities during the Long Shutdown 1: The LHC’s injector chain.

vacuum, linac, ion, operation

2291

J.A. Ferreira Somoza, P. Chiggiato
CERN, Geneva, Switzerland

During the long shutdown 1 (LS1), several maintenance, consolidation and upgrade activities have been carried out in LHC’s injector chain. Each machine has specific vacuum requirements and different history, which determine the present status of the vacuum components, their maintenance and consolidation needs. The present work presents the priorities agreed at the beginning of the LS1 period and their implementation. Of particular relevance are the interventions in radioactive controlled areas where several leaks due to stress corrosions stopped the operations in the past years. The strategy to reduce the collective dose is presented, in particular the use of remote controlled robots. An important part of the work performed during this period involves supporting other teams (acceptance tests, new equipment installation, etc.). Finally, as a result of the LS1 experience, a medium to long term strategy is depicted, focusing on the preparation of the next shutdown (LS2) and the integration of LINAC4 in the injector chain during the same period.

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WEPME025

Design and Performance of Ultimate Vacuum System for the AREAL Test Facility

vacuum, cathode, dipole, electron

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.

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WEPME032

Detailed Investigation of the Low Energy Secondary Electron Yield of Technical Cu and its Relevance for LHC

electron, 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.

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WEPME057

The Secondary Electron Yield from Transition Metals

electron, vacuum, 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.

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WEPME060

Yb DOPED HIGH-ENERGY UV ULTRAFAST LASER FOR AREAL FACILITY

laser, electron, 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.

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WEPME061

Ytterbium Fiber and Disk Laser of RF Gun for SuperKEKB

laser, cavity, background, emittance

2415

X. Zhou, T. Natsui, Y. Ogawa, M. Yoshida
KEK, Ibaraki, Japan

For SuperKEKB project, the electron beams with a charge of 5 nC and a normalized emittance of 10 μm are expected to be generated in the photocathode RF gun at the injector linac. An ytterbium (Yb)-doped laser system with a center wavelength of 259 nm and a pulse width of 30 ps is employed to obtain high peak energy pulses. Although, the pulse repetition of 25 Hz with double-bunch is required, more than 5 nC electron with single-bunch has so far been generated in the 2 Hz.

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WEPME065

European XFEL RF Gun Commissioning and LLRF Linac Installation

LLRF, linac, klystron, cryomodule

2427

J. Branlard, G. Ayvazyan, V. Ayvazyan, L. Butkowski, M.K. Grecki, M. Hoffmann, F. Ludwig, U. Mavrič, S. Pfeiffer, H. Schlarb, Ch. Schmidt, H.C. Weddig, B.Y. Yang
DESY, Hamburg, Germany
S. Bou Habib, K. Czuba, M. Grzegrzółka, E. Janas, J. Piekarski, I. Rutkowski, R. Rybaniec, D. Sikora, L.Z. Zembala, M. Żukociński
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
W. Cichalewski, D.R. Makowski, A. Mielczarek, P. Perek, A. Piotrowski, T. Pożniak
TUL-DMCS, Łódź, Poland
S. Korolczuk, I.M. Kudla, J. Szewiński
NCBJ, Świerk/Otwock, Poland
K. Oliwa, W. Wierba
IFJ-PAN, Kraków, Poland

The European x-ray free electron laser (XFEL) is based on a 17.5 GeV super conducting pulsed linac and is scheduled to deliver its first beam in 2016. The first component of its accelerator chain, the RF gun, was installed in fall of 2013 and its commissioning is underway. This contribution gives an update on the low level radio frequency (LLRF) system development and installation for the XFEL. In particular, the installation, performance and conditioning results of the RF gun are presented. The subsequent steps toward LLRF components mass-production, testing and installation for the XFEL linac are also explained.

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WEPME066

High Speed Digitial LLRF Feedbacks for Normal Conducting Cavity Operation

LLRF, cavity, operation, klystron

2430

M. Hoffmann, L. Butkowski, H. Schlarb, Ch. Schmidt
DESY, Hamburg, Germany
W. Köhler
DESY Zeuthen, Zeuthen, Germany
A. Piotrowski
TUL-DMCS, Łódź, Poland
I. Rutkowski, R. Rybaniec
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland

In the first half of the year 2014, the MTCA.4 based LLRF control system will be installed at several facilities (FLASH RF Gun, REGAE, PITZ, FLUTE/KIT). First tests during the last year show promising results in optimizing the system for high speed digital llrf feedbacks (reducing system latency, increase internal controller processing speed). In this contribution we will present further improvements in latency and performance optimization of the system, results and gained experience from the commisioning of the system at the metioned facilities.

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WEPRI018

Status of the Fabrication of the XFEL 3.9 GHz Cavity Series

cavity, status, linac, vacuum

2512

C. Maiano, M. Bertucci, A. Bosotti, J.F. Chen, P. Michelato, L. Monaco, M. Moretti, C. Pagani, R. Paparella, P. Pierini, D. Sertore
INFN/LASA, Segrate (MI), Italy

The third harmonic system at 3.9 GHz of the European XFEL (E-XFEL) injector section will linearize the bunch RF curvature, induced by first accelerating module, before the first compression stage and it is a joint INFN and DESY contribution to the project. This paper presents the status of the fabrication of the 3.9 GHz cavity series in view of the XFEL injector commissioning in 2015.

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WEPRI025

Studies of Fabrication Procedure of 9-cell SRF Cavity for ILC Mass-production at KEK.

cavity, HOM, electron, 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.

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WEPRI058

Commissioning Status of the Advanced Superconducting Test Accelerator at Fermilab

laser, cryomodule, cavity, cathode

2615

J. Ruan, R. Andrews, C.M. Baffes, D.R. Broemmelsiek, K. Carlson, B. Chase, M.D. Church, D.J. Crawford, E. Cullerton, J.S. Diamond, N. Eddy, D.R. Edstrom, E.R. Harms, A. Hocker, A.S. Johnson, A.L. Klebaner, M.J. Kucera, J.R. Leibfritz, A.H. Lumpkin, J.N. Makara, S. Nagaitsev, O.A. Nezhevenko, D.J. Nicklaus, L.E. Nobrega, P.S. Prieto, J. Reid, J.K. Santucci, G. Stancari, D. Sun, M. Wendt, S.J. Wesseln
Fermilab, Batavia, Illinois, USA
P. Piot
Northern Illinois University, DeKalb, 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) is under construction at Fermilab. This accelerator will consist of a photo-electron gun, injector, ILC-type cryomodules, and multiple downstream beam-lines. Its purpose is to be a user-based facility for Advanced Accelerator R&D. . Following the successful commissioning of the photoinjector gun, a Tesla style 8-cavity cryomodule and a high gradient capture cavity have been cooled down to 2 K and powered commissioning and performance characterization has begun. We will report on the commissioning status and near-term future plans for the facility.

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WEPRI059

Assembly and Installation of the UV Laser Delivery and Diagnostic Platform and the Photocathode Imaging System for the ASTA Front-end

laser, optics, diagnostics, vacuum

2618

D.J. Crawford, R. Andrews, T.W. Hamerla, J. Ruan, J.K. Santucci, 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.
The Advanced Superconducting Test Accelerator (ASTA) is in the early stage of commissioning. 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 area for measuring the characteristics of the photoelectron beam. We report on the design, construction, and early experience of the ultra-violet (UV) Laser Delivery and Diagnostic Platform and the Photocathode Imaging System.

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THPRO025

Conceptual Design of a X-FEL Facility using CLIC X-band Accelerating Structure

linac, FEL, klystron, simulation

2914

A.A. Aksoy, O. Yavaş
Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
D. Angal-Kalinin, J.A. Clarke
Cockcroft Institute, Warrington, Cheshire, United Kingdom
M.J. Boland
SLSA, Clayton, Australia
G. D'Auria, S. Di Mitri, C. Serpico
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
M. Doğan
Dogus University, Istanbul, Turkey
T.J.C. Ekelöf, R.J.M.Y. Ruber, V.G. Ziemann
Uppsala University, Uppsala, Sweden
W. Fang, Q. Gu
SINAP, Shanghai, People's Republic of China
A. Latina, D. Schulte, S. Stapnes, I. Syratchev, W. Wuensch
CERN, Geneva, Switzerland
Z. Nergiz
Nigde University, Nigde University Science & Art Faculty, Nigde, Turkey

Within last decade a linear accelerating structure with an average loaded gradient of 100 MV/m at 12 GHz has been demonstrated in the CLIC study. Recently, it has been proposed to use the CLIC structure to drive an FEL linac. In contrast to CLIC the linac would be powered by klystrons not by a drive beam. The main advantage of this proposal is achieving the required energies in a very short distance, thus the facility would be rather compact. In this study, we present the conceptual design parameters of a facility which could generate laser photon pulses covering the range of 1-75 Angstrom. Shorter wavelengths could also be reached with slightly increasing the energy.

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THPRO028

Bunch Compressor Design for CLIC Drive Beam

linac, cathode, linear-collider, collider

2924

A.A. Aksoy
Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
J. Esberg, D. Schulte
CERN, Geneva, Switzerland

The drive-beam linac which is required for generation RF power at Compact Linear Collider (CLIC) has to accelerate an electron beam with 8.4 nC per bunch up to 2.4 GeV in almost fully loaded structures. The required beam stability in both transverse and longitudinal directions are of concern for such a high bunch charge. We present different bunch compressor designs for the Drive Beam and compare their performance including the effects beam energy and phase jitters.

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THPRO029

A Front End for the CLARA FEL Test Facility at Daresbury Laboratory

linac, dipole, bunching, emittance

2927

P.H. Williams, D. Angal-Kalinin, J.A. Clarke, B.D. Fell, J.K. Jones, J.W. McKenzie, B.L. Militsyn
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The next step towards the full CLARA facility is installation of the CLARA front end to comprise a 2m S-band linac section after the photoinjector gun. This will be suitable for both the velocity bunching and standard booster modes of CLARA. An S-bend will also be installed to deflect the beam into the current VELA line, enabling delivery of higher energy beams to two existing user areas. The current photoinjector beam diagnostics section can then be used to test a High Repetition Rate electron gun currently under development. We describe the proposed CLARA front end design. We define two beam dynamics working points for CLARA, one working point for sending beam from the CLARA Front End to VELA, and one working point to feed an interim user station prior to CLARA full construction in the straight-on position.

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THPRO031

Short Pulses THz FEL for the Oxford Accelerator Science Laboratory

FEL, radiation, cavity, undulator

2934

T. Chanwattana, R. Bartolini, A. Seryi
JAI, Oxford, United Kingdom
R. Bartolini
DLS, Oxfordshire, United Kingdom
E. Tsesmelis
CERN, Geneva, Switzerland

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 short pulse THz FEL based on a conventional RF accelerator driven by a RF photocathode gun is being investigated. This report presents the concept of the facility, the accelerator physics and FEL studies and engineering integration in the University physics department.

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THPRO042

Field Emission Studies of Heat Treated Mo Substrates

SRF, cathode, electron, 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.

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THPRO044

Report on Gun Conditioning Activities at PITZ in 2013

cathode, cavity, vacuum, FEL

2962

M. Otevřel, P. Boonpornprasert, J.D. Good, M. Groß, I.I. Isaev, D.K. Kalantaryan, M. Khojoyan, G. Kourkafas, M. Krasilnikov, D. Malyutin, D. Melkumyan, T. Rublack, F. Stephan, G. Vashchenko
DESY Zeuthen, Zeuthen, Germany
G. Asova
INRNE, Sofia, Bulgaria
P. Boonpornprasert, S. Rimjaem
Chiang Mai University, Chiang Mai, Thailand
F. Brinker, K. Flöttmann, S. Lederer, B. Marchetti, S. Schreiber
DESY, Hamburg, Germany
Ye. Ivanisenko
PSI, Villigen PSI, Switzerland
M.A. Nozdrin
JINR, Dubna, Moscow Region, Russia
G. Pathak
Uni HH, Hamburg, Germany
D. Richter
BESSY GmbH, Berlin, Germany

Recently three RF guns were prepared at the Photo Injector Test Facility at DESY, location Zeuthen (PITZ) for their subsequent operation at FLASH and the European XFEL. The gun 3.1 is a previous cavity design and is currently installed and operated at FLASH, the other two guns 4.3 and 4.4 were of the current cavity design and are dedicated to serve for the start-up of the European XFEL photo-injector. All three cavities had been dry-ice-cleaned prior their conditioning and hence showed low dark current levels. The lowest dark current level – as low as 60μA at 65MV/m field amplitude – has been observed for the gun 3.1. This paper reports in details about the conditioning process of the most recent gun 4.4. It informs about experience gained at PITZ during establishing of the RF conditioning procedure and provides a comparison with the other gun cavities in terms of the dark currents. It also summarizes the major setup upgrades, which have affected the conditioning processes of the cavities.

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THPRO045

Design and Construction of a Thermionic Cathode RF Electron Gun for Iranian Light Source Facility

electron, 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.

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THPRO048

Emittance and Bunch Length Measurement of the Electron Beams from the NSRRC Photocathode Gun

emittance, electron, 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.

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THPRO051

Cavity Design for a S-Band Photoinjector RF Gun with 400 Hz Repetition Rate

cavity, FEL, cathode, emittance

2983

J.W. McKenzie, L.S. Cowie, P. Goudket, B.L. Militsyn
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
T.J. Jones
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
V.V. Paramonov
RAS/INR, Moscow, Russia

As part of the design of CLARA (Compact Linear Accelerator for Research and Applications), the proposed UK FEL test facility at Daresbury Laboratory, a high repetition rate S-band photoinjector RF gun is being developed. This gun will be able to operate at up to 400 Hz repetition rate in single bunch mode. We present the initial cavity design including its optimisation for the beam dynamics of CLARA. We also present the initial cooling design for the cavity which will enable the high repetition rates to be achieved.

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THPRO052

Beam Physics Commissioning of VELA at Daresbury Laboratory

emittance, laser, diagnostics, quadrupole

2986

B.L. Militsyn, D. Angal-Kalinin, A.D. Brynes, F. Jackson, J.K. Jones, A. Kalinin, J.W. McKenzie, B.D. Muratori, T.C.Q. Noakes, D.J. Scott, E.W. Snedden, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
M.D. Roper
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

A user facility VELA (Versatile Electron Linear Accelerator) based on an RF photoinjector has been commissioned at Daresbury Laboratory in April 2013, providing beam to first users in September 2013. Machine study runs in 2013-2014 have concentrated on characterisation of main beam parameters like bunch charge, its momentum, beam emittance and dependence of these parameters on the launching RF phase. Major efforts have been also concentrated on investigation of the dark current from the gun and its dependence on the RF amplitude. Significant time has been dedicated to investigation of relative stability of LLRF and drive laser having significant impact on the overall machine stability. We present here the results of these studies.

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THPRO054

LLNL X-band Test Station Commissioning and X-ray Status

laser, vacuum, alignment, emittance

2992

R.A. Marsh, G.G. Anderson, S.G. Anderson, C.P.J. Barty, M. Betts, S.E. Fisher, D.J. Gibson, F.V. Hartemann, S.S.Q. Wu
LLNL, Livermore, California, USA

Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344
An X-band test station is being commissioned at LLNL to support inverse Compton-scattering x-ray and gamma-ray source development. The X-band test station has been built and this presentation will focus on its current status and the generation of first electron beam. Special focus will be placed on the high gradient conditioning of the T53 traveling wave accelerator and Mark 1 X-band standing wave RF gun. Design and installation of the inverse-Compton scattering interaction region, future upgrade paths and configuration for a variety of x-ray and gamma-ray applications will be discussed along with the status of theory and modeling efforts.

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THPRO074

Characterization of the Longitudinal Wakefields in the MAX IV Linac

linac, wakefield, simulation, FEL

3050

O. Karlberg, F. Curbis, S. Thorin, S. Werin
MAX-lab, Lund, Sweden

In the second part of 2014, the 3GeV linac at the MAX IV laboratory will enter its commissioning stage. Equipped with two guns, the linac will act as a full energy injector for the two storage rings and at the same time provide high brightness pulses to a Short Pulse Facility (SPF). Compression in the linac is done in two double achromats with fixed R56 that relies upon the RF phase introduced energy chirp, which in this case is strongly enhanced by the longitudinal wakefields. Since the longitudinal wakefields plays a major role in the compression and bunch shaping they need to be carefully investigated during the commissioning. In this proceeding we will discuss a measurement technique that will be used during commissioning to characterize the longitudinal wakefields and their precise effects on e.g. the bunch shape and the energy spread. Predictions obtained from particle tracking will be presented.

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THPRO093

Low Emittance Electron Beam Transportation in Compact ERL Injector

cathode, focusing, laser, solenoid

3104

T. Miyajima, K. Harada, Y. Honda, T. Kume, S. Nagahashi, N. Nakamura, T. Obina, S. Sakanaka, M. Shimada, R. Takai, T. Uchiyama, A. Ueda, M. Yamamoto
KEK, Ibaraki, Japan
R. Hajima, R. Nagai, N. Nishimori
JAEA, Ibaraki-ken, Japan
J.G. Hwang
Kyungpook National University, Daegu, Republic of Korea

For future light source based on Energy Recovery Linac (ERL), an injector, which consists of a photocathode DC gun and superconducting RF cavities, is a key part to generate a low emittance, short pulse and high bunch charge electron beam. In compact ERL (cERL) which is a test accelerator to develop key technologies for ERL, the generation of low emittance electron beam with 0.1 mm mrad normalized emittance and 390 keV beam energy from the photocathode DC gun, and the acceleration to 5.6 MeV by superconducting cavity, were demonstrated in the first beam commissioning. To keep the high quality in the beam transportation, understanding the beam optics, which is affected by not only the focusing effects due to the gun, solenoid magnets and RF cavities but also space charge effect, is required. In this presentation, we will show that how to measure and correct the focusing effect by experimental method. Using this method, we succeeded in correcting the analytical model to give the good agreement with the measured gun focusing for low charge beam. And, we will show the space charge effect for high bunch charge beam.

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THPRO127

Current Status of TARLA Control System

controls, EPICS, LabView, operation

3192

E. Kazancı, A.A. Aksoy, A. Aydin, C. Kaya, B. Tonga, O. Yavaş
Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
S. Özkorucuklu
Istanbul University, Istanbul, Turkey

Funding: This study was funded by Ministry of Development of Turkey by grant id DPT2006K-120470
Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) is a Free Electron Laser (FEL) facility designed to generate Free Electron Laser (FEL) in 3-250 um wavelength range, based on four 9-cell Super Conducting (SC) cavities with 10MeV/m gradient each. TARLA electron gun has been in operation since 2012. Control system studies with EPICS are being run as test stand control and permanent system and each are running as individual projects while test stand control is in stable revision. The aim of the system design is to create a fast and reliable control system which is easy to operate and extensible for future upgrades/improvements. Now, the development and implementation of control system is ongoing in a parallel manner with the rest of the accelerator as well as the architectural design, In this study, the permanent and the test stand control systems of TARLA will be discussed.
On behalf of TARLA Team

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THPME079

Beam Diagnostics and Control for the AREAL RF Photogun Linac

controls, diagnostics, linac, electron

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.

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THPME095

Length Measurement of High-brightness Electron Beam thanks to the 3-Phase Method

electron, 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)

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THPME123

Electro-optical Bunch Length Monitor for FLUTE: Layout and Simulations

electron, laser, simulation, linac

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

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THPME132

Generation and Diagnosis of Ultrashort Electron Bunches from a Photocathode RF Gun Linac

electron, detector, linac, 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).

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THPME133

Bunch Length Measurement with 2-Cell RF-Deflector at Waseda University

electron, cavity, 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.

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THPME137

Preliminary Study of Non-invasive Beam Profile Measurements for Proton Beams

electron, proton, 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.

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THPME146

Bunch Length Measurement by Using a 2-Cell Superconducting RF Cavity in cERL Injector at KEK

cavity, electron, experiment, 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.

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THPME192

Assembly and Installation of Beam Instrumentation for the ASTA Front-end Diagnostic Table

diagnostics, target, laser, electron

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.

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THPME193

GUI Development for the Drive Laser at Fermilab's ASTA Facility

laser, controls, status, interface

3735

D.R. Edstrom, E.R. Harms, T.R. Johnson, A.H. Lumpkin, J. Ruan, J.K. Santucci
Fermilab, Batavia, Illinois, USA

A comprehensive set of graphical user interfaces is being developed for the drive laser of the Advanced Superconducting Test Accelerator (ASTA) facility at Fermilab. These interfaces have been designed in Synoptic, a Java-based GUI development platform with credential-dependent access to the Fermilab accelerator controls network. Such implementation facilitates the user's ability to monitor and control many aspects of the drive laser system in an intuitive environment, as well as timely updates on the part of the developers made necessary by the evolving drive laser system. Furthermore, the current interface hierarchy readily allows integration into the larger pool of Synoptic applications being developed for other subsystems at ASTA.

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THPRI031

Design and Commissioning of S-Band RF Station for AREAL Test Facility

electron, 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.

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THPRI032

Study of a RF Gun with a Thermoionic Cathode

cavity, injection, simulation, space-charge

3837

A.S. Setty, A.S. Chauchat, D. Fasse, D. Jousse, P. Sirot
Thales Communications & Security (TCS), Gennevilliers Cedex, France

The low energy part of our pre injectors* is made up of a 90 kV DC thermoionic triode gun, followed by a 500 MHz sub harmonic prebuncher and a 3 GHz prebuncher. These two cavities are respectively fed with 500 W, a modulation of ± 25 kV, and 90 W corresponding to a ± 10 kV. The gun grid is modulated within a 500 MHz signal. The initial 1 ns phase extension at the gun level is reduced, at the buncher entry, to 40 ps for 75% of the gun current. This study proposes to replace the gun and the two cavities by a RF gun integrated in a modulated cavity at 200 MHz followed by a drift in order to bunch the beam. This study will compare the beam dynamics simulations for these two cases.
*A. Setty et al, "Design and Construction of Turnkey Linacs as Injectors for Light Sources", Proceedings IPAC 2012, USA, Louisiana, May 2012.

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THPRI038

Simulation Study of Electron Gun for Six MeV Linac for X-Ray Cargo Inspection

electron, 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.

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THPRI043

Thermal-mechanical Analysis of the RF Structures for the ELI-NP Proposal

RF-structure, linac, cathode, HOM

3860

V. Pettinacci
INFN-Roma, Roma, Italy
D. Alesini, L. Pellegrino
INFN/LNF, Frascati (Roma), Italy
L. Palumbo
URLS, Rome, Italy

The room temperature RF structures in the ELI-NP Linac will operate in multi-bunch with high repetition rate (100 Hz). For these reasons they are subject to some kW of power dissipated on the internal cavities surfaces. The resulting thermal deformation of the cavities shapes could imply variations in their electromagnetic fields. To limit these effects and optimize the cooling design, a fully coupled ElectroMagnetic- Thermal-Mechanical analysis has been performed on the S-Band Radiofrequency Gun and on the C-Band multi-cell structures. In the paper the study done in Ansys Workbench with HFSS and Ansys Mechanical is reviewed

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THPRI045

Development of a 1.3-GHz Buncher Cavity for the Compact ERL

cavity, operation, vacuum, simulation

3866

T. Takahashi, Y. Honda, T. Miura, T. Miyajima, H. Sakai, S. Sakanaka, K. Shinoe, T. Uchiyama, K. Umemori, M. Yamamoto
KEK, Ibaraki, Japan

In a high-brightness injector of the Compact ERL (cERL), a 1.3-GHz buncher cavity is used to compress the electron bunches which are produced at a 500-kV photocathode DC electron gun. An rf voltage required is about 130 kV. To elongate the lifetime of the photocathode of the DC gun which is located beside the buncher cavity, an extremely-low pressure of about 10^-9 Pa is required in the buncher cavity under operating conditions. In order to achieve such low pressures, we have developed a normal-conducting cavity which included several measures to reduce the outgas from the cavity components, together with careful rf designs to avoid any problems due to multipactor discharges or to other problems. With the developed cavity, we achieved a vacuum pressure of about 2·10^-9 Pa under rf operations at an rf voltage of about 100 kV. The buncher cavity was installed in the cERL, and it worked very well; we could demonstrate to compress the bunch length from 10 ps (FWHM) to 0.5 ps (rms) using the buncher cavity.

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THPRI059

Field Emission Study of RF cavity in Static Magnetic Field

cathode, cavity, solenoid, electron

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.

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THPRI060

Conceptual Design of an Electromagnetic Driven Undulator Based Positron Target System for ILC

target, positron, vacuum, photon

3908

W. Gai, W. Liu
ANL, Argonne, Illinois, USA

There have been intense activities on development of the fast spinning Ti wheel positron target for ILC in the last few years. As in many high power target design, it requires solutions for many technical challenges, such as vacuum, thermal stress and radiation damage control, just to name a few. Due to the unique beam timing structure, in this paper, we present a target system based on a electromagnetic mechanical system that drives a bullet type Ti slug (~ 1.4x1.4x10 cm, weigh ~ 50 g) as the target system. The mechanism is similar to a reloadable EM rail gun driven projectiles. The system can be compact, vacuum isolated, and ease of cooling. Conceptual design layout and parameter estimations are presented.

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THPRI076

Laser Triggered RF Breakdown Study Using an S-band Photocathode Gun

laser, experiment, HOM, cathode

3943

J.H. Shao, W. Gai
ANL, Argonne, Illinois, USA
H.B. Chen, Y.-C. Du, W.-H. Huang, J. Shi, C.-X. Tang, L.X. Yan
TUB, Beijing, People's Republic of China
C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
F.Y. Wang
SLAC, Menlo Park, California, USA

A laser triggered RF breakdown experiment was carried out with an S-band photocathode gun at Tsinghua University for attempting understanding of the RF breakdown processes. By systematic measurement of the time dependence of the breakdown current at the gun exit and the stored RF energy in the cavity, one might gain insight into the time evolution of RF breakdown physics. A correlation of the stored energy and field emission current has been analysed with an equivalent circuit model. Experimental details and analysis methods are reported.

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THPRI077

Electric Field Enhancement Study using an L-band Photocathode Gun

cathode, experiment, simulation, pick-up

3946

J.H. Shao, W. Gai
ANL, Argonne, Illinois, USA
H.B. Chen, J. Shi
TUB, Beijing, People's Republic of China
C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
F.Y. Wang, L. Xiao
SLAC, Menlo Park, California, USA

RF breakdown in high gradient accelerating structures is a fundamental problem that is still needed better understanding. Past studies have indicated that field emission, which is usually represented by electric field enhancement (i.e. β) produced from the Fowler-Nordheim plot, is strongly coupled to the breakdown problem. A controlled surface study using a high gradient L-band RF gun is being carried out. With a flat cathode, the maximum electric field on the surface reached 10³ MV/m. And electric field as high as 565 MV/m on the surface was achieved by a pin-shaped cathode. The field enhancement factor was measured at different surface field during the conditioning process. Initial results of the study are presented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI077

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THPRI100

Distributed Cooling System for the AREAL Test Facility

klystron, electron, 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

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