EPAC08 - List of Keywords (gun)

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gun

Paper	Title	Other Keywords	Page
MOZAG01	Simulations of the Emittance Compensation in Photoinjectors and Comparison with SPARC Measurements	emittance, simulation, linac, space-charge	21
	C. Ronsivalle, L. Giannessi, M. Quattromini ENEA C. R. Frascati, Frascati (Roma) A. Bacci, A. R. Rossi, L. Serafini INFN-Milano, Milano E. Chiadroni, M. Ferrario, L. Ficcadenti, D. Filippetto, V. Fusco, B. Marchetti, M. Migliorati, A. Mostacci, L. Palumbo, C. Vaccarezza INFN/LNF, Frascati (Roma) A. Cianchi INFN-Roma II, Roma
	FEL photoinjectors are based on the emittance compensation process, by which a high brightness beam can be accelerated without degradation. The experimental results obtained in the SPARC facility for which the beam dynamics has been extensively simulated confirm the theoretical predictions. The paper illustrates the most relevant beam dynamics results as well as a comparison between simulations and measurements.
	Slides

MOZBM01	High Intensity and Low Emittance Guns	electron, cathode, laser, emittance	46
	P. M. Michelato INFN/LASA, Segrate (MI)
	High intensity or high-brilliance, low emittance electron beams are needed for many applications, ranging from SASE FELs to fast radiolysis systems, from Compton backscattering X ray sources to energy recovery linac, from CW FELs to the linear collider. They are produced using a high field RF accelerating structure together with a photoemissive electron source: the rapid acceleration process minimizes the space charge effects which tend to spoil the emitted beam characteristics. The talk will review the technology and provide the important parameters of these sources as the generated bunch charge, the repetition rate, the mean and peak current, the beam emittance, etc, together with an analysis of gun reliability and technological challenges. I will present the state of the art of the technology of the RF guns, either using metallic or semiconductor photoemitters. New high repetition rate/CW sources, appearing in the last years, using superconducting cavities, will be also reviewed.
	Slides

MOPC004	First Results from the Upgraded PITZ Facility	laser, diagnostics, electron, cathode	70
	J. W. Baehr, S. Lederer DESY, Hamburg G. Asova INRNE, Sofia C. H. Boulware, H.-J. Grabosch, M. Hänel, Ye. Ivanisenko, S. Khodyachykh, S. A. Korepanov, M. Krasilnikov, B. Petrosyan, S. Rimjaem, T. A. Scholz, R. Spesyvtsev, L. Staykov, F. Stephan DESY Zeuthen, Zeuthen L. Hakobyan YerPhI, Yerevan R. Richter BESSY GmbH, Berlin J. Roensch Uni HH, Hamburg K. Rosbach Humboldt University Berlin, Institut für Physik, Berlin A. Shapovalov MEPhI, Moscow
	During autumn and winter 2007 a general reconstruction of the PITZ facility was performed. A new spectrometer based on a dipole magnet with 180 degree deflection angle was inserted in the facility. The new spectrometer contains two screen stations for the measuring of the longitudinal phase space and the slice emittance. A new "Conditioning Test Stand" (CTS) was added to the facility. Using this CTS a new electron gun having an improved cooling system is under conditioning. A new photocathode laser system (developed by MBI) was installed and commissioned. The goal is to reach rise and fall times of the laser pulses of 2 ps. The system of laser diagnostic was upgraded. The results reached using this upgraded facility are reported. This concerns the conditioning results of the new gun. Furthermore, a gun will be characterised using the new diagnostics beamline and the new photocathode laser. Results of the commissioning and first measurements of the new diagnostics components will be reported.

MOPC006	Seeding of the Test FEL at MAX-lab	laser, electron, alignment, linac	76
	N. Cutic, F. Curbis, F. Lindau, S. Thorin, S. Werin MAX-lab, Lund
	The test FEL at MAX-lab has recently been completed. The system will be seeded at 263 nm by a tripled Ti:sapphire laser synchronized to the RF system and the gun laser. Issues important for the seeding will be presented, ranging from the laser system via the layout of photon and electron optics to timing/synchronization and the theoretical approach. Experimental results on the seeding operation will also be presented.

MOPC007	Status and Upgrade Program of the FERMI@ELETTRA Linac	linac, laser, klystron, controls	79
	G. D'Auria, A. O. Borga, S. Di Mitri, O. Ferrando, G. C. Pappas, A. Rohlev, A. Rubino, C. Serpico, M. Trovo, A. Turchet, D. Wang ELETTRA, Basovizza, Trieste
	FERMI@ELETTRA is a seeded FEL user facility under construction at Sincrotrone Trieste, Italy. It will use the existing normal conducting S-band linac and with the installation of seven accelerating sections received from CERN after the LIL decommissioning, will be operated at 1.2 GeV. After the successful commissioning of the new injector system of ELETTRA, the linac has been disconnected from the storage ring and now is being revised and upgraded with the installation of new important subsystems, i.e., a new photoinjector, bunch compressors, laser heater, additional accelerating structures, etc. Here a description of the upgrade program as well as the ongoing activities on the main parts of the machine are reported and discussed.

MOPC010	Injector System for X-ray FEL at SPring-8	emittance, bunching, linac, electron	85
	H. Hanaki, T. Asaka, H. Ego, H. Kimura, T. Kobayashi, S. Suzuki JASRI/SPring-8, Hyogo-ken T. Hara, A. Higashiya, T. Inagaki, N. Kumagai, H. Maesaka, Y. Otake, T. Shintake, H. Tanaka, K. Togawa RIKEN/SPring-8, Hyogo
	The SPring-8 X-FEL based on the SASE process has been developed to generate X-rays of 0.1 nm by the combination of an 8 GeV high gradient linac (400 m) and a mini-gap undulator of in-vacuum type (90 m). The design goals of the slice beam emittance and peak current at the end of the linac are 1 π mm mrad and 3 kA, respectively. The injector of the linac generates an electron beam of 1 nC, accelerates it up to 30 MeV, and compresses its bunch length down to 20 ps step by step. The injector has been designed on the basis of the SCSS test accelerator. We adopted the following keys to toward the goals: A 500 kV thermionic gun (CeB6) without a control grid ejecting a beam holding the low rms emittance of 1.1 π mm mrad, a beam deflector downstream gating the beam to form a bunch of a 1 ns length, multi-stage RF structures (238, 476 and 1428 MHz) bunching and accelerating the beam gradually to maintain the initial emittance, and extra RF cavities of 1428 and 5712 MHz linearizing the energy chirp of the beam bunch to achieve the bunch compression resulting the required peak current.

MOPC015	Start-to-End Simulations of the PSI 250 MeV Injector Test Facility	emittance, linac, booster, simulation	100
	Y. Kim, A. Adelmann, R. J. Bakker, M. Dehler, R. Ganter, T. Garvey, A. Oppelt, M. Pedrozzi, J.-Y. Raguin, L. Rivkin, A. Streun, F. Stulle, A. F. Wrulich PSI, Villigen
	From 2003, PSI has been investigating the advanced Low Emittance Gun (LEG) based 6 GeV PSI XFEL facility to supply coherent, ultra-bright, and ultra-fast XFEL photon beams covering from 0.1 nm to 10 nm. To build whole facility within a 800 m space, required beam parameters in front of undulators are challenging. For the first two FEL beamlines (FEL 1 and FEL 2), the required normalized slice emittance, slice energy spread, and peak current are about 0.2 mm.mrd, 0.6 MeV, and 1.5 kA, respectively. However, the required beam parameters for the third FEL beamline (FEL 3) covering 1 nm to 10 nm are somewhat flexible. Therefore PSI has been developing two different gun technologies. The 1 MV high gradient pulsed diode and field emission based advanced LEG will be used for first two FEL beamlines, while the CTF3 gun type V based conventional RF photoinjector will be used for the third FEL beamline. To test those two injector technologies, a dedicated 250 MeV injector test facility will be constructed at PSI from 2008. In this paper, we describe beam dynamics in two accelerator optimizations of the CTF3 RF gun based 250 MeV injector test facility for the PSI XFEL project.

MOPC016	Status of the CUTE-FEL Project	undulator, linac, electron, klystron	103
	S. Krishnagopal, B. Biswas, S. K. Gupta, U. Kale, A. Kumar, V. Kumar, S. Lal, P. Nerpagar, K. K. Pant, A. Patel RRCAT, Indore (M. P.)
	We are building a Compact Ultrafast TErahertz Free-Electron Laser (CUTE-FEL), designed to lase around 80 microns, driven by a 10 MeV electron beam, and using a 5 cm period, 2.5 m long undulator. We present the latest status of the project, including acceleration and commissioning trials.

MOPC019	Velocity Bunching at FLASH	emittance, bunching, electron, simulation	112
	T. Limberg, B. Beutner, W. Decking, M. Huening, M. Krasilnikov, M. Vogt DESY, Hamburg O. Grimm Uni HH, Hamburg
	The vacuum-ultra-violet free electron laser in Hamburg (FLASH) is a linac driven SASE-FEL. High peak currents are, in routine operation, produced using magnetic bunch compression chicanes. Longitudinal dispersion in these chicanes allow bunch length changes of relativistic electron beams. For low energy electron beams (~5 MeV), the velocity dependence on electron energy can be utilized for bunch compression. Since strong bunch compression at low beam energies gives rise to strong space charge interactions which has an impact on, for instance, beam emittance and is therefore not suitable for full compression to the kA peak currents needed for SASE operation. Moderate velocity bunching, however, might be used to optimize the total bunch compression system of FLASH or the European XFEL. Experiments on the velocity bunching process at FLASH are presented here. Results on bunch length and transverse emittance measurements are discussed and compared with numerical tracking calculations.

MOPC023	ARC-EN-CIEL Beam Dynamics	emittance, laser, brightness, space-charge	115
	A. Loulergue, M.-E. Couprie SOLEIL, Gif-sur-Yvette C. Bruni LAL, Orsay
	ARC-EN-CIEL project is based on a CW 1.3 GHz superconducting linac accelerator delivering high charge, subpicosecond and low emittance electron bunches at high repetition rate. According to the electron energy, it provides tunable light source of high brightness in the VUV to soft X-ray wavelength domain. The project will evolve into three phases: first and second phases are based on high brightness single pass SC linac configuration with a low average current (few μA), while third phase comports recirculation loops to increase the average current (up to 100 mA). This paper deals with electron beam dynamics issues for the single pass configuration in the two first phases from the RF gun to undulators including magnetic compression stages. In the ERL configuration of the third phase, the accelerator scheme and focusing are investigated in order to take into account collective effects as Beam Break Up instability.

MOPC030	Operation of FLASH at 6.5 nm Wavelength	radiation, laser, electron, linac	133
	S. Schreiber, B. Faatz, K. Honkavaara DESY, Hamburg
	FLASH, the Free-Electron-Laser at DESY, Germany has been upgraded in 2007. A 6th accelerating module with eight 9-cell superconducting cavities of the TESLA type has been installed. In addition, another module has been replaced and the tuners of a third module have been repaired. In September 2007, a beam energy of 1 GeV has been achieved for the first time, followed by lasing at 6.5 nm shortly after. With this remarkable achievement, the initial design goals of the FEL in terms of beam energy and wavelength have been reached.

MOPC031	Status of X-ray FEL/SPring-8 Machine Construction	undulator, electron, emittance, cathode	136
	T. Shintake RIKEN/SPring-8, Hyogo
	XFEL/SPring-8: the X-ray Free Electron Laser Project is under construction at SPring-8 site, which is aiming at generating 0.1 nm coherent radiation using 8 GeV electron beam. After the ground breaking in 2007, concrete piling has been completed. Construction of the accelerator tunnel will be completed in end of the FY2008, then machine installation will be started. The first electron beam acceleration is scheduled in FY2010. XFEL/SPring-8 based on SASE-FEL, and unique design, thermionic CeB6 gun, adiabatic bunching, C-band high gradient accelerator and in vacuum undulator. To reach 8 GeV within 400 m available tunnel length, we use 64 C-band klystron, which drives 128 accelerating tube at 37 MV/m.

MOPC032	Progress of the Commissioning of the Test FEL at MAX-lab	laser, simulation, electron, emittance	139
	S. Thorin, F. Curbis, N. Cutic, F. Lindau, S. Werin MAX-lab, Lund M. Abo-Bakr, J. Bahrdt, K. Holldack BESSY GmbH, Berlin
	In a collaboration between MAX-lab and BESSY a seeded Harmonic Generation Free Electron Laser is being constructed at MAX-lab. The setup uses the existing MAX-lab facility together with a Ti:Sa 266 nm lasersytem used for both the gun and seeding and an optical klystron consisting of a modulator, a chicane and a radiator. The different parts of the system has been installed and commissioning with electrons of the full setup started during the fall of 2007. In this paper the progress of the commissioning of the Test FEL and our initial results are presented.

MOPC033	Sapphire - A High Peak Brightness X-Ray Source as a Possible Option for a Next Generation UK Light Source	linac, emittance, klystron, undulator	142
	R. P. Walker, C. Christou, J. H. Han, J. Kay Diamond, Oxfordshire R. Bartolini JAI, Oxford
	In the UK there is increasing interest in a radiation source which would provide ultra-fast (from 100 fs down to a few fs and potentially below) multi-keV X-ray pulses with high peak brightness, in order to study rapid dynamical processes in electronic and molecular systems, complementary to the newly operational Diamond Light Source which has been designed principally for high time-averaged X-ray brightness. In this paper we present the results of our initial studies for one option for a cost-effective, staged, linac based source suitable as a national facility which can act additionally as a portal to larger X-ray free-electron laser facilities in Europe, the US and Japan.

MOPC035	PULSE - A High-Repetition-Rate Linac Driver for X-ray FELs	electron, emittance, laser, undulator	148
	P. H. Williams, B. L. Militsyn, H. L. Owen, M. W. Poole, N. Thompson STFC/DL/ASTeC, Daresbury, Warrington, Cheshire B. W.J. McNeil USTRAT/SUPA, Glasgow
	We describe a staged concept for a linac-based free-electron laser providing coherent tunable VUV and soft X-ray output with pulse lengths less than 10 fs. Use of recent developments in high brightness injectors and 1.3 GHz cryomodules gives stable, reliable output with very good electron beam quality and flexible pulse pattern. Options for achieving repetition rates up to 1 MHz are examined. We also consider the development and demonstration of novel FEL concepts that access photon pulses in the attosecond regime. The combination of these parameters would open up new areas in femtosecond and attosecond science.

MOPC057	R&D Energy Recovery Linac at Brookhaven National Laboratory	linac, electron, klystron, diagnostics	193
	V. Litvinenko, D. Beavis, I. Ben-Zvi, M. Blaskiewicz, A. Burrill, R. Calaga, P. Cameron, X. Chang, K. A. Drees, G. Ganetis, D. M. Gassner, H. Hahn, L. R. Hammons, A. Hershcovitch, H.-C. Hseuh, A. K. Jain, A. Kayran, J. Kewisch, R. F. Lambiase, D. L. Lederle, G. J. Mahler, G. T. McIntyre, W. Meng, T. C. Nehring, B. Oerter, C. Pai, D. Pate, D. Phillips, E. Pozdeyev, T. Rao, J. Reich, T. Roser, T. Russo, K. Smith, J. E. Tuozzolo, D. Weiss, N. Williams, K. Yip, A. Zaltsman BNL, Upton, Long Island, New York H. Bluem, M. D. Cole, A. J. Favale, D. Holmes, J. Rathke, T. Schultheiss AES, Medford, NY J. R. Delayen, L. W. Funk, H. L. Phillips, J. P. Preble Jefferson Lab, Newport News, Virginia
	Collider Accelerator Department at BNL is in the final stages of developing the 20-MeV R&D energy recovery linac with super-conducting 2.5 MeV RF gun and single-mode super-conducting 5-cell RF linac. This unique facility aims to address many outstanding questions relevant for high current (up to 0.5 A of average current), high brightness energy-recovery linacs with novel Zigzag-type merger. We present the performance of the R&D ERL elements and detailed commissioning plan.

MOPC058	ALICE (ERLP) Injector Design	booster, emittance, laser, cathode	196
	B. D. Muratori, Y. M. Saveliev STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
	In this paper we look at how the ALICE (formerly ERLP) injector has been re-designed to meet more realistic criteria from the previous design. A key component of ALICE is the high brightness injector. The ALICE injector consists of a DC photocathode gun generating 80 pC electron bunches at 350 keV. These bunches are then matched into a booster cavity which accelerates them to an energy of 8.35 MeV. In order to do this, two solenoids and a single-cell buncher cavity are used, together with off-crest injection into the first booster cavity, where the beam is still far from being relativistic. The performance of the injector has been studied using the particle tracking code ASTRA.

MOPC061	Progress in R&D Efforts on the Energy Recovery Linac in Japan	linac, laser, electron, synchrotron	205
	S. Sakanaka, T. A. Agoh, A. Enomoto, S. Fukuda, K. Furukawa, T. Furuya, K. Haga, K. Harada, S. Hiramatsu, T. Honda, Y. Honda, K. Hosoyama, M. Izawa, E. Kako, T. Kasuga, H. Kawata, M. Kikuchi, H. Kobayakawa, Y. Kobayashi, T. Matsumoto, S. Michizono, T. Mitsuhashi, T. Miura, T. Miyajima, T. Muto, S. Nagahashi, T. Naito, T. Nogami, S. Noguchi, T. Obina, S. Ohsawa, T. Ozaki, H. Sasaki, S. Sasaki, K. Satoh, M. Satoh, M. Shimada, T. Shioya, T. Shishido, T. Suwada, T. Takahashi, Y. Tanimoto, M. Tawada, M. Tobiyama, K. Tsuchiya, T. Uchiyama, K. Umemori, S. Yamamoto KEK, Ibaraki R. Hajima, H. Iijima, N. Kikuzawa, E. J. Minehara, R. Nagai, N. Nishimori, M. Sawamura JAEA/ERL, Ibaraki H. Hanaki JASRI/SPring-8, Hyogo-ken A. Ishii, I. Ito, T. Kawasaki, H. Kudo, N. Nakamura, H. Sakai, S. Shibuya, K. Shinoe, T. Shiraga, H. Takaki ISSP/SRL, Chiba M. Katoh UVSOR, Okazaki Y. Kobayashi, K. Torizuka, D. Yoshitomi AIST, Tsukuba M. Kuriki HU/AdSM, Higashi-Hiroshima
	The future synchrotron light sources, based on the energy recovery linacs (ERL), are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. The ERL-based light sources are under development at such institutes as the Cornell University, the Daresbury Laboratory, the Advanced Photon Source, and KEK/JAEA. The Japanese collaboration team, including KEK, JAEA, ISSP, and UVSOR, is working to realize the key technologies for the ERLs. Our R&D program includes the developments of ultra-low-emittance photocathode DC guns and of superconducting cavities, as well as proofs of accelerator-physics issues at a small test ERL (the Compact ERL). A 250-kV, 50-mA photo-cathode DC gun is under construction at JAEA. Two single-cell niobium cavities have been tested under high electric fields at KEK. The conceptual design of the Compact ERL has been carried out. We report recent progress in our R&D efforts.

MOPC062	Results from ALICE (ERLP) DC Photoinjector Gun Commissioning	emittance, kicker, laser, electron	208
	Y. M. Saveliev, D. J. Holder, B. D. Muratori, S. L. Smith STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
	The Energy Recovery Linac Prototype (ERLP) DC photoinjector gun has been commissioned and the beam characteristics measured. The gun has demonstrated the nominal ERLP parameters of 350 keV electron energy, 80pC bunch charge and ~140 ps bunch length (at 10% level). The bunch parameters were measured at different bunch charges from 1 pC up to 80 pC. Special attention was given to measurements of the beam transverse emittance (using a movable slit), correlated and uncorrelated energy spread (using an energy spectrometer) and bunch length (using a transverse RF kicker) at each bunch charge. The effect of the 1.3 GHz RF buncher on the bunch length was also investigated. The experimental results are then compared with ASTRA simulations. Experimental results obtained from the investigation of several other issues including the beam characteristics in the presence of field emission from the cathode and in the presence of strong beam halo are also presented and discussed.

MOPC063	Characterisation of Electron Bunches from ALICE (ERLP) DC Photoinjector Gun at Two Different Laser Pulse Lengths	laser, emittance, electron, simulation	211
	Y. M. Saveliev, S. P. Jamison, L. B. Jones, B. D. Muratori STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
	In high-voltage DC photoinjector guns, the laser pulse duration affects the electron bunch characteristics and therefore is an important subject for experimental investigation and in the optimisation of the operation of the gun. Initial experimental study of this effect has been conducted using the Energy Recovery Linac Prototype (ERLP) photoinjector. During the commissioning of its DC photoinjector gun, the electron bunch parameters were measured at two laser pulse durations, ~7ps and ~28ps FWHM. The shorter laser pulse is the intrinsic output of the laser, while the longer pulse was produced with the use of a pulse stacker. The electron bunch parameters that were measured included transverse emittance, correlated and uncorrelated energy spread and bunch length. The experimental results and their comparison with computer simulations are presented and discussed.

MOPC065	Wake Field Simulations for Structures of the PITZ RF Photoinjector: Emittance growth estimations	emittance, simulation, diagnostics, electron	217
	E. Arevalo, W. Ackermann, E. Gjonaj, W. F.O. Müller, S. Schnepp, T. Weiland TEMF, Darmstadt
	One of the main concerns in the design of electron guns is the generation of low-emittance beams. One source of emittance growth is the beam-surrounding effect, which can be estimated from the wake potentials along the beam path. For the calculation of these potentials an accurate knowledge of the short range wake fields induced in the different parts of the gun with geometrical discontinuities is necessary. The computation of these wake fields is a challenging problem, as an accurate resolution for both the small bunch and the large model geometry is needed. Here with the help of numerical wake-potential calculations we analytically estimate the emittance growth for the RF electron gun of the Photoninjector Test Facility at DESY Zeuthen (PITZ).

MOPC066	Optimisation of a SRF High Average Current SRF Gun	cathode, emittance, laser, acceleration	220
	C. D. Beard, J. W. McKenzie, B. L. Militsyn, B. D. Muratori STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
	An approximately 100 mA and 10 MeV continuous wave electron injector is required to deliver high brightness electron bunches for the spontaneous and VUV radiation sources. One of possible solutions might be a Superconductive RF (SRF) gun. Optimisation of the first half cell of the gun has been carried out to maximise the acceleration whilst providing additional focussing through shaping of the cathode region to meet the design specification. In this paper, the cavity design and specification are presented together with some initial optimisations.

MOPC067	Normal Conducting CW RF Gun Design for High Performance Electron Beams	cathode, emittance, simulation, electron	223
	H. Bluem, T. Schultheiss, L. M. Young AES, Medford, NY R. A. Rimmer Jefferson Lab, Newport News, Virginia
	High repetition rate (>1 MHz), high charge (1 nC), low emittance (1 micron) electron beams are an important enabling technology for next generation light sources. Advanced Energy Systems has begun the development of an advanced, continuous-wave, normal-conducting radio frequency electron gun. This gun is designed to minimize thermal stress, allowing fabrication in copper, while providing low emittance electron beams. Beam dynamics performance will be presented along with thermal and stress analysis of the gun cavity design.

MOPC068	Preliminary Characterization of the Beam Properties of the SPARC Photoinjector	emittance, quadrupole, cathode, linac	226
	A. Cianchi INFN-Roma II, Roma D. Alesini, M. Castellano, E. Chiadroni, L. Cultrera, G. Di Pirro, M. Ferrario, L. Ficcadenti, D. Filippetto, V. Fusco, G. Gatti, B. Marchetti, E. Pace, C. Vaccarezza, C. Vicario INFN/LNF, Frascati (Roma) A. Mostacci Rome University La Sapienza, Roma C. Ronsivalle ENEA C. R. Frascati, Frascati (Roma)
	The SPARC photoinjector is the test prototype of the recently approved SPARX project. It is used as R&D facility to perform accurate beam dynamics studies, comparing measurements and simulations. Emittance measurements at the gun exit and at the full energy has been performed and benchmarked with the simulations.

MOPC071	Development of a High Brightness Photo-Injector for Light Source Research at NSRRC	laser, electron, emittance, brightness	229
	W. K. Lau, J. H. Chen, C. S. Chou, G.-Y. Hsiung, K. T. Hsu, J.-Y. Hwang, A. P. Lee, C. C. Liang, G.-H. Luo, D.-J. Wang NSRRC, Hsinchu C. H. Chen, N. Y. Huang, Y.-C. Huang, W. K. Luo NTHU, Hsinchu
	A laser driven photo-cathode rf gun system is being installed at NSRRC gun testsite for high brightness electron beam and light source research. The photo-cathode rf gun cavity geometry has been modified from the BNL 1.6-cell structure for 2998 MHz operation. A 798 nm Ti:Saphire laser seeded 3 mJ regenerative amplifier is employed to produce 300 microjoules UV pulses at 266 nm wavelength from a third harmonic generator crystal for emission of photo-electrons from the Cu-cathode in the rf gun. First operation of this system with gaussian laser pulses is scheduled in summer 2008. Future plan for flattop laser pulse operation will be discussed.

MOPC073	Design of an Upgrade to the ALICE Photocathode Electron Gun	electron, vacuum, cathode, laser	235
	B. L. Militsyn, B. D. Fell, L. B. Jones, J. W. McKenzie, K. J. Middleman STFC/DL/ASTeC, Daresbury, Warrington, Cheshire I. Burrows, R. J. Cash STFC/DL, Daresbury, Warrington, Cheshire S. N. Kosolobov, H. E. Scheibler, A. S. Terekhov ISP, Novosibirsk
	The design of an upgrade to the GaAs photocathode electron gun of the Energy Recovery Linac Prototype (ERLP) at Daresbury Laboratory is presented. This proposed upgrade includes a reduction of the photocathode diameter from 32 to 10 mm and the installation of a dedicated photocathode preparation system with side loading of the photocathodes. The preparation system forms a united vacuum system with the gun but is separated by a gate valve. This allows for significant improvements to the vacuum conditions in the gun and a reduction of pollution from caesium vapour which improves gun stability under high voltage. This preparation facility will reduce the time taken for photocathode changeover from weeks to hours. The facility should provide photocathodes with higher quantum efficiency due to a more controllable preparation procedure and allows experiments to be performed with photocathodes activated to different levels of electron affinity.

MOPC074	3D Simulations of a Non-axisymmetric High Average Current DC Photocathode Electron Gun	cathode, electron, simulation, ion	238
	J. W. McKenzie, B. L. Militsyn STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
	At high average currents, GaAs photocathode based electron guns are limited by the short operational lifetime of the photocathodes. One method to improve the cathode lifetime is to situate the photocathode off-axis to reduce the flow of ions back-bombarding the emitting surface. The results of 3D electrostatic and beam dynamic simulations are presented to demonstrate the feasibility of this scheme and the resultant beam quality achievable.

MOPC075	Cs2Te Photocathode Robustness Studies	cathode, vacuum, ion, emittance	241
	D. Sertore, P. M. Michelato, L. Monaco, C. Pagani INFN/LASA, Segrate (MI) S. Lederer, S. Schreiber DESY, Hamburg F. Stephan DESY Zeuthen, Zeuthen
	Cs2Te photocathodes are used as laser driven electron sources at FLASH and PITZ. Besides many aspects of their performances, their robustness to gas exposition and the effect of pollutants on photocathode properties, and indirectly on the photoemitted electrons, are a field still rather unexplored. In this article we present the results of controlled exposition of Cs2Te photocathodes to gases typical present in the UHV environment of an RF Gun with respect to spectral response (QE vs. wavelength), and QE uniformity. Moreover, a comparison between polluted cathodes and fresh ones during operation in an RF Gun is presented.

MOPC078	Tuning and Conditioning of a New High Gradient Gun Cavity at PITZ	electron, emittance, cathode, controls	244
	S. Rimjaem, G. Asova, J. W. Baehr, C. H. Boulware, H.-J. Grabosch, M. Hänel, Ye. Ivanisenko, M. Krasilnikov, S. Lederer, A. Oppelt, B. Petrosyan, T. A. Scholz, A. Shapovalov, R. Spesyvtsev, L. Staykov, F. Stephan DESY Zeuthen, Zeuthen K. Floettmann, D. Reschke DESY, Hamburg L. Hakobyan YerPhI, Yerevan R. Richter BESSY GmbH, Berlin J. Roensch Uni HH, Hamburg
	A new 1.3 GHz photo cathode electron gun (prototype 4.2) for the Photo Injector Test facility in Zeuthen (PITZ) was tuned in February 2007. The main difference in the mechanical design compared to earlier guns is a significantly improved cooling system. This gun is also the first copper gun cavity where a particle free cleaning using dry ice technique was applied while in the previous guns the high pressure ultra pure water rinsing technique was used. The cavity has been installed in a new Conditioning Test Stand (CTS) at PITZ in autumn 2007. It has been conditioned to an accelerating gradient of 60 MV/m and more. Dark current measurements have been performed to monitor the improvement of conditioning and to compare with the results from the previous guns. In this paper, RF measurement and tuning results as well as results of the conditioning and dark current measurements will be presented and discussed.

MOPC080	Status of the FERMI@Elettra Photoinjector	laser, electron, diagnostics, controls	247
	M. Trovo, L. Badano, S. Biedron, D. Castronovo, F. Cianciosi, P. Craievich, G. D'Auria, M. B. Danailov, M. Ferianis, S. V. Milton, G. Penco, L. Pivetta, L. Rumiz, D. Wang ELETTRA, Basovizza, Trieste H. Badakov, A. Fukasawa, B. D. O'Shea, J. B. Rosenzweig UCLA, Los Angeles, California M. Eriksson, D. Kumbaro, F. Lindau MAX-lab, Lund
	The new FERMI@Elettra photoinjector is presently undergoing high-power testing and characterization at MAX-Lab in Lund Sweden. This effort is a collaboration between Sincrotrone Trieste, MAX-Lab and UCLA. The 1.6-cell RF gun cavity and the focusing solenoid were successfully designed and built by the Particle Beam Physics Laboratory at UCLA, delivered to Sincrotrone Trieste at the beginning of 2008, and installed in the linac tunnel at MAX-Lab. Use of the MAX-Lab facility will allow the FERMI project to progress significantly with the photoinjector while waiting for the completion of the new linac building extension at Sincrotrone Trieste. We report here on the high-power conditioning of the RF cavity and the first beam tests. Furthermore, a preliminary characterization of the 5 MeV beam will also be presented.

MOPC083	Flat Long Pulse Train Formation Using Multi-pass Structure	laser, insertion, alignment, polarization	250
	J. Ruan, H. T. Edwards, R. P. Fliller Fermilab, Batavia, Illinois
	Flat long pulse train is part of the requirements for International Linear collider. Here in Fermilab the construction of ILCTA at New Meon Lab will present the similar requirements (3MHz, 2810 Pulses, 5Hz) for the laser systems. In this paper we will report the effort to develop a new multi pass (MP) cavity based on Nd:YLF crystal end-pumped by diode laser. It takes a seed (1054 nm, 4-5ps) from a commercial laser and has a gain of 1000 or more. So far we already tested up to 1000 pulses with 1μs spacing and the pulse train amplitude fluctuation is less than 5% throughout the whole duration. We attribute this to the high optical to optical conversion efficiency achieved using Nd:YLF crystal inside the multi-pass structure. Test with 3MHz spacing train is also discussed and the integration of the new MP cavity into the current laser system is planned.

MOPC088	High Power Neutron Converter for Low Energy Proton/Deuteron Beams: Test Facility	target, controls, electron, vacuum	265
	V. Gubin, A. V. Antoshin, M. S. Avilov, M. F. Blinov, D. Bolkhovityanov, V. A. Golikov, M. A. Kholopov, N. N. Lebedev, P. V. Logachev, V. S. Popov, S. V. Shiyankov, A. S. Tsyganov, I. E. Zhul BINP SB RAS, Novosibirsk
	This paper presents conceptual design of test facility, that is now under creation in the framework of development of high power neutron targets for SPES (INFN-LNL, Italy) and SPIRAL-II (GANIL, France). General destination of facility is to test different target systems and elements (hot converter unit, liquid metal driving gear and cooling systems) as well as experimental checking of supply, protection and control methods etc. Also, this facility must be used as a base for input quality control of targets as a whole in future. The structure, general features and experimental possibilities of facility are described.

MOPC141	Design of a Novel Tubular Electron String Ion Source (TESIS)	ion, electron, extraction, ion-source	403
	E. Syresin, D. E. Donets, E. D. Donets, E. E. Donets, V. B. Shutov JINR, Dubna, Moscow Region V. M. Drobin, A. V. Shabunov, Yu. A. Shishov JINR/LHE, Moscow A. E. Dubinov, R. M. Garipov, I. V. Makarov VNIIEF, Sarov (Nizhnii Gorod) L. Liljeby MSL, Stockholm
	The project, started in 2007 is directed to creation of Tubular Electron String Ion Source (TESIS) and to basic studies of electron strings in tubular geometry. The collaboration consists of JINR (Dubna) and Russian Federal Nuclear Center (Sarov, Russia), Manne Siegbahn Laboratory (Stockholm, Sweden), TRIUMF and Atomic Energy of Canada Ltd. (Canada). Tubular concept of ion source has been proposed few years ago. Preliminary theoretical estimations and numerical simulations have been done,** that allowed to start experimental realization of this project. New tubular source with a superconducting solenoid up to 5 Tesla should be constructed in 2009. It is expected that this new TESIS (“Krion-T1”) will meet all rigid conceptual and technological requirements and should provide ion output on a level, approaching to 10 mA of Ar¹⁶⁺ ions in the pulse mode and about 10 mA of Ar¹⁶⁺ ions in the average current mode. Having these output parameters, “Krion-T1” TESIS should be an operational prototype of further TESIS sources for all kinds of the possible applications. Simulation results and a basic scetch of the TESIS construction will be presented. Donets E. D. et al. Rev. Sci. Instrum. 73, 696 (2002). Donets E. D., Donets E. E., Becker R. et al. Rev. Sci. Instrum.75, 1566 (2004). **Donets E. E. J. of Phys.: Conf. Series 2, 97 (2004).

MOPC154	Method for Efficiency and Time Response Measurement on Diverse Target Ion Sources with Stable Alkali	ion, ion-source, target, plasma	436
	A. Pichard, J. A. Alcantara Nunez, R. Alves Conde, M. Dubois, R. Frigot, P. Jardin, P. Lecomte, J. Y. Pacquet, M. G. Saint-Laurent GANIL, Caen
	Developments of new setups for radioactive ion beam production by the isotope-separator-on-line (ISOL) method are underway at GANIL in the frame of the SPIRAL (Système de Production d’Ions Radioactifs Accélérés en Ligne) and SPIRAL-II projects. The measurement of total efficiency and time behaviour of these new target/ion-source systems (TISSs) is a crucial step for these devices which aims to produce short-lived isotopes with high intensity. The overall atom-to-ion transformation efficiency depends on several processes: diffusion of the atoms out of the production target, effusion towards the ion source and ionization. The efficiency can be extracted using the ratio between the emerging yield and implanted flux in the TISS. Several methods have already been developed to achieve these measurements: the use of stable or radioactive beams, gas injection, or the introduction of solid material into the TISS. This paper focuses primarily on a method that uses stable alkali. A pulsed/CW alkali ion gun has been built and will be used to optimise diverse TISSs. [1] C. Eléon et al., Proceedings of the XVe International Conference EMIS, 24-29th June 2007, Deauville, France, to be published.

MOPD004	CPI RF Components for the ILC	klystron, electron, vacuum, controls	454
	T. A. Treado, S. J. Einarson, T. W. Habermann CPI, Beverley, Massachusetts
	Communications & Power Industries, Inc. (CPI) has active programs to refine key components for the European XFEL. These components, the fundamental power coupler and the multibeam klystron (MBK) are also suited for the International Linear Collider (ILC). CPI power couplers are manufactured to our customer's specifications using processes which are standard to the electron device industry as well as processes which are specific to power couplers. We have developed the capability of plating high-RRR copper on stainless steel. We have developed the capability of applying TiN coatings to ceramic windows. Both processes are done in-house under carefully controlled conditions. Both processes have been fully qualified. CPI has manufactured nearly 100 power couplers of various designs. Our presentation will focus on power couplers for the XFEL and the ILC. CPI is currently developing a second-generation, horizontal MBK for DESY. This MBK operates at 10 MW, at an RF frequency of 1.3 GHz, 1.5 ms pulse length, and 10 Hz pulse repetition rate. Our presentation will provide an update on this development program.

MOPD012	Half Wave Injector Design for WiFEL	emittance, cathode, space-charge, linac	469
	R. A. Legg UW-Madison/SRC, Madison, Wisconsin W. Graves MIT, Cambridge, Massachusetts T. L. Grimm Niowave, Inc., Lansing, Michigan P. Piot Fermilab, Batavia, Illinois
	Seeded FELs will require exceptional beam quality. The Wisconsin FEL (WiFEL) requires peak currents of greater than 1 kA with less than 1 mm-mrad transverse slice emittance and 1·10^-4 δp/p at the undulator. To perform the obligatory bunch compression after the injector without allowing micro-bunching will require very smooth bunch energy and density profiles and relatively low compression ratios. An injector which uses a low frequency, superconducting, half wave resonator gun combined with self-inflating, ellipsoidal bunches* to meet those requirements is described. The superconducting radio frequency TEM-class cavities have been in use for more than 25 years and because of their potential for flat field profiles, are desirable as electron gun structures. A Superfish model and field map of the specific gun cavity is presented. ASTRA** simulations from the cathode to 120MeV are provided. A description is given of the technique used to emittance compensate the space charge induced energy chirp while maintaining the peak bunch current. * O. J.Luiten, et al., Phys. Rev. Lett. Vol 93, 094802 (2004) ** K. Floetmann, ASTRA, www.desy.de/~mpyflo

MOPD025	Status of the 805-MHz Pulsed Klystrons for the Spallation Neutron Source	klystron, cathode, factory, electron	499
	S. Lenci, E. L. Eisen CPI, Palo Alto, California M. P. McCarthy ORNL, Oak Ridge, Tennessee
	Communications and Power Industries, Inc (CPI) produced 81 klystrons for the Spallation Neutron Source at Oak Ridge National Laboratory. The klystrons are rated for 550 kW peak at 805 MHz. Seventy units have accumulated 1.2M hours of filament operation and 820K hours of high voltage operation through January 2008. A higher power 700 kW version has been developed and is now in production with 12 of the 38 units on order delivered through January 2008. Performance specifications, computer model predictions, operating results, production statistics, and operational status will be presented.

MOPD042	Design and Testing of the Horizontal Version of the Multi Beam Klystron for European XFEL Project	klystron, electron, cathode, linac	544
	Y. Yano, M. Y. Miyake, Y. Okubo, S. Sakamoto Toshiba Electron Tubes & Devices Co., Ltd (TETD), Tochigi Y. H. Chin KEK, Ibaraki K. Hayashi, K. Tetsuka, H. Urakata TETD, Otawara
	Toshiba Electron Tubes & Devices (TETD) has been developing 10-MW L-band Multi-Beam Klystrons (MBKs) for the European XFEL project and possibly for future linear colliders. In order to allow horizontal installation in the XFEL tunnel, the horizontal version of MBK, MBK E3736H, has been designed, fabricated and tested by TETD. The MBK has six low-perveance beams operated at low voltage of less than 120 kV (for 10MW) and six ring-shaped cavities. In the successful acceptance testing at TETD in August 2007, the MBK achieved an output power of 10.3 MW at the beam voltage of 117 kV and at the RF pulse width of 1.5ms with efficiency of 67%. This test demonstrated that MBK E3736H fulfills all the requirements necessary as the RF power source of the XFEL linac.

MOPP076	L-Band RF Gun with a Thermionic Cathode	cathode, simulation, emittance, controls	727
	S. Nagaitsev, R. Andrews, M. Church, A. Lunin, O. A. Nezhevenko, N. Solyak, D. Sun, V. P. Yakovlev Fermilab, Batavia, Illinois
	In this talk we present a design for an L-band (1.3 GHz) rf gun with a two-grid thermionic cathode assembly. The rf gun is design to provide a 10-mA average beam current for 1ms at 5 Hz. These parameters match the requirements of both the ILC and Fermilab Project X test facilities. In our simulations we are able to attain the bunch length at 20-30 degrees (FW), while the output energy can vary 2-4 MeV. We will present the results of our simulations as well as preliminary designs.

MOPP078	Femtosecond Photocathode Electron Source	laser, electron, emittance, injection	730
	J. Yang, K. Kan, T. Kondoh, K. Tanimura, Y. Yoshida ISIR, Osaka J. Urakawa KEK, Ibaraki
	A photocathode-based low-emittance femtosecond-bunch electron source is developed to reveal the hidden dynamics of intricate molecular and atomic processes in materials through experimentation such as time-resolved pulse radiolysis or time-resolved electron diffraction. The transverse and longitudinal dynamics of femtosecond electron beam in a photocathode rf gun were studied. The growths of the emittance, bunch length and energy spread due to the rf and the space charge effects in the rf gun were investigated by changing the laser injection phase, the laser pulse width and the bunch charge. The beam simulation indicates that a sub-100-fs MeV electron source with the normalized transverse emittance of 0.1 mm-mrad and the relative energy spread of 10^-4 at bunch charge of 0.1-1pC is achievable in the photocathode rf gun driven by a femtosecond laser light.

MOPP086	A Novel Fabrication Technique for the Production of RF Photoinjectors	electron, vacuum, controls, coupling	751
	P. Frigola, R. B. Agustsson, S. Boucher, A. Y. Murokh RadiaBeam, Los Angeles D. Cormier, T. Mahale NCSU, Raleigh L. Faillace Rome University La Sapienza, Roma J. B. Rosenzweig, G. Travish UCLA, Los Angeles, California
	Recent developments in Direct Metal Free Form Fabrication (DMFFF) technology may make it possible to design and produce near netshape copper structures for the next generation of very high duty factor, high gradient radio frequency (RF) photoinjectors. RF and thermal-management optimized geometries could be fully realized without the usual constraints and compromises of conventional machining techniques. A photoinjector design incorporating DMFFF and results from an initial material feasibility study will be reported.

MOPP100	Performance of Compact Electron Injector on Evanescent Oscillations	electron, coupling, cathode, resonance	790
	V. V. Mytrochenko, M. I. Ayzatskiy, I. V. Khodak, K. Kramarenko, V. A. Kushnir, A. Opanasenko, S. A. Perezhogin, D. L. Stepin, Z. V. Zhiglo NSC/KIPT, Kharkov
	An injector on the basis of a resonator structure with exponentially increasing amplitude of the electric field along an axis was developed at NSC KIPT. The injector is supplied with RF power through a rectangular-to-coaxial waveguide transition to provide axial symmetry of the accelerating field. The injector was designed to provide the output current up to 1 A at particle energy up to 1 MeV. Results of the injector test are presented in the work. Results obtained are compared with calculated ones.

MOPP109	Status of the 100 MeV Preinjector for the ALBA Synchrotron	linac, diagnostics, single-bunch, electron	811
	A. Falone, D. Einfeld, M. Pont ALBA, Bellaterra D. Jousse, J.-L. Pastre, F. Rodriguez, A. S. Setty THALES, Colombes A. Sacharidis EuroMev, Buc
	A turn key 100 MeV linac has been constructed by THALES in order to inject electrons into the booster synchrotron of ALBA. The linac will be commissioned in May 2008. This paper will remind the main features of the linac* and will give results obtained during the commissioning tests. The energy and emittance measurements will be done on the transfer line conceived and realized by CELLS. * D. Einfeld "Status of ALBA", PAC07, Albuquerque, USA, June 2007. ** A. Setty "Beam dynamics of the 100 MeV preinjector for the spanish synchrotron ALBA", PAC07, Albuquerque, USA, June 2007.

MOPP141	Commissioning of the ERLP SRF Systems at Daresbury Laboratory	booster, linac, radiation, shielding	889
	P. A. McIntosh, R. Bate, R. K. Buckley, S. R. Buckley, P. A. Corlett, A. J. Moss, J. F. Orrett, S. M. Pattalwar, A. E. Wheelhouse STFC/DL/ASTeC, Daresbury, Warrington, Cheshire F. G. Gabriel FZD, Dresden A. R. Goulden STFC/DL/SRD, Daresbury, Warrington, Cheshire P. vom Stein ACCEL, Bergisch Gladbach
	The Energy Recovery Linac Prototype (ERLP) has been installed at Daresbury Laboratory and its baseline commissioning completed. The SRF systems for ERLP comprise two 9-cell, 1.3 GHz accelerating cavities in the injector (or Booster) cryomodule, which provide a nominal energy gain of 8 MeV for the injected 350 keV beam from the photo-injector. The beam is then accelerated in an identical two cavity cryomodule in the energy recovery main Linac, giving a final ERLP energy of 35 MeV. Each SRF accelerating cavity is powered by commercially available Inductive Output Tubes (IOTs) and the analog LLRF control system is identical to that employed on the ELBE facility at FZD Rossendorf. This paper details the commissioning experience gained for these systems and highlights the ultimate performance achieved.

TUOAM02	The Status of the Daresbury Energy Recovery Linac Prototype	linac, diagnostics, laser, radiation	1001
	D. J. Holder, P. A. McIntosh, S. L. Smith STFC/DL/ASTeC, Daresbury, Warrington, Cheshire N. Bliss STFC/DL, Daresbury, Warrington, Cheshire A. R. Goulden STFC/DL/SRD, Daresbury, Warrington, Cheshire
	This paper provides an update on the progress with the building and commissioning of the Energy Recovery Linac Prototype (ERLP). The past year has seen a number of notable achievements as well as a number of obstacles to overcome. The detailed results from the gun commissioning work are described elsewhere at this conference. ERLP is a 35 MeV technology demonstrator being built as part of the UK's R&D programme to develop its next-generation light source (NLS). It is based on a combination of a DC photocathode electron gun, a superconducting injector linac and a main linac operating in energy recovery mode. These drive an IR-FEL, an inverse Compton Back-Scattering (CBS) x-ray source and a terahertz beamline. The priorities for ERLP are to gain experience of operating a photoinjector gun and superconducting linacs; to produce and maintain high-brightness electron beams; to achieve energy recovery from an FEL-disrupted beam; the development of an electro-optic longitudinal profile monitor and to study challenging synchronisation issues. ERLP will also act as an injector for what will be the world's first non-scaling, Fixed-Field Alternating Gradient (FFAG) accelerator called EMMA.
	Slides

TUPC001	Optics Calculation and Emittance Measurement toward Automatic Beam Tuning of Linac	linac, emittance, optics, simulation	1035
	T. Asaka, H. Dewa, H. Hanaki, T. Kobayashi, A. Mizuno, S. Suzuki, T. Taniuchi, H. Tomizawa, K. Yanagida JASRI/SPring-8, Hyogo-ken T. Watanabe SES, Hyogo-pref.
	The SPring-8 1-GeV linac has a total of 13 sets of 80MW klystron units. In usual operation, two klystron units are driven as the standby unit. If there's any problem with an arbitrary klystron unit, the beam operation is able to restart immediately by using the standby unit. In that case, the optimization of beam optics has carried out using beam screen monitors. This beam tuning spend about one hour. In order to reduce the beam tuning time, we are promoting the development of the automatic beam optics tuning system. Since the complete understanding of the beam envelope is important, the particles tracking simulation of the linac was carried out by using PARMELA and SAD. Five sets of beam size monitors were installed in the end of the linac for measurement of the real beam envelope. In a beam study applying the simulation results, the beam waist was actually formed at the 10-m long drift space after the 1-GeV chicane section as predicted by SAD. The values of the measured beam emittance were smaller than the simulation results.

TUPC032	Phase Space Tomography Using the Cornell ERL DC Gun	emittance, quadrupole, electron, diagnostics	1119
	F. E. Hannon Jefferson Lab, Newport News, Virginia I. V. Bazarov, B. M. Dunham, Y. Li, X. G. Liu Cornell University, Department of Physics, Ithaca, New York
	The brightness and quality of electron beams in linac-based light sources are ultimately limited by the properties of the beam in the injector. It is thus important to have knowledge of the phase space distribution in addition to the rms emittance to provide an insight into high beam brightness formation mechanisms. A tomography technique has been used to reconstruct the transverse phase space of the electron beam delivered from the Cornell University ERL DC gun. The tomography diagnostic utilised three solenoid magnets directly after the DC gun and a view-screen. The injector was operated at 250keV in the emittance dominated regime, and the results showed good agreement to the phase space measured using a slit-screen method and that generated from simulation with the particle tracking code ASTRA. Comparison of various reconstruction methods is provided.

TUPC045	Setup and Commissioning of the Diagnostics Beamline for the SRF Photoinjector Project at Rossendorf	laser, electron, diagnostics, cathode	1158
	T. Kamps, D. Böhlick, M. Dirsat, T. Quast, J. Rudolph, M. Schenk BESSY GmbH, Berlin A. Arnold, F. Staufenbiel, J. Teichert FZD, Dresden G. Klemz, I. Will MBI, Berlin D. Lipka DESY, Hamburg
	A superconducting radio frequency photo electron injector (SRF injector) has been developed by a collaboration of BESSY, DESY, FZD and MBI and is in operation since late 2007. After the initial commissioning in late 2007 with a Copper photocathode a Caesium-Telluride cathode was installed early 2008 to allow for high charge production. The longitudinal and transverse electron beam parameters are measured in a compact diagnostics beamline. This paper describes results from beam commissioning of the main diagnostic tools. Special emphasis is given on the bunch length measurement system for the 15 ps FWHM electron bunches. The system is based on the conversion of the electron pulses into radiation pulses by Cherenkov radiation. These radiation pulses are transported in a novel fully-reflective, relay imaging optical beamline to a streak camera, where the temporal properties of the pulses are measured. Results from beam measurements at 2pC (Copper cathode) and 1nC (Cesium-Telluride cathode) bunch charge are presented and discussed.

TUPC078	The Gun Spectrometer Design for the FERMI@Elettra Project	quadrupole, space-charge, simulation, diagnostics	1233
	G. Penco, D. Castronovo, M. Trovo, D. Zangrando ELETTRA, Basovizza, Trieste
	In the FERMI linac layout the first spectrometer has been located close to the exit of the photoinjector gun at about 5 MeV. The main purpose of this equipment is measuring the energy and energy spread of the beam. Combining the spectrometer with Yag screens and Cerenkov radiators allows the investigation and characterization of eventual deterioration of the longitudinal profile due to the space charge forces and microbunching instabilities. The design specification of the magnet and multi-particle tracking code simulation results are presented in this paper.

TUPC113	Beam Energy Compensation by RF Amplitude Control for Thermionic RF Gun and Linac Based Mid-infrared FEL	controls, klystron, electron, beam-loading	1329
	H. Zen, T. Kii, R. Kinjo, K. Masuda, H. Ohgaki, S. Sasaki, T. Shiiyama Kyoto IAE, Kyoto
	Institute of Advanced Energy, Kyoto University has constructed a mid-infrared FEL facility which consists of a thermionic RF gun, a traveling-wave type accelerating tube and a halbach type undulator. The electron beam quality is critical for lasing FEL. However, we found that the beam energy after the accelerator tube decreased from 25 to 23.5 MeV (around 6%) during macro-pulse duration (~4μsec), because.the beam current increases from 65 to 120 mA during the macro-pulse due to the backbombardment effect in the RF gun. To compensate the energy drop and to minimize the energy spread over the macro-pulse, the amplitude of RF power fed to the tube was controlled. Since a precise micro-bunch interval required to build up the FEL, the RF phase was also controlled. As the result, the energy spread of the electron beam was greatly reduced from 6 to 0.8% in FWHM which was same with micro-pulse energy spread (~0.8%). The phase stability during macro-pulse was also improved from 10 to less than 2 degree.

TUPD041	The Design of a 5 MeV Accelerator Based on Multipactor Electron Gun	electron, cathode, emittance, coupling	1520
	M. Zhong, C.-X. Tang, S. Zheng TUB, Beijing
	The Multipactor Electron Gun (MPG) based on the multipactor effect can produce short duration, high current and self-bunching electron beams. This paper presents our work on the design of an S-band accelerator based on MPG and the result of preliminary experiment. The mechanical structure was designed with ability of replacing secondary electron emitters. Pd-Ba alloy and Pt were used as the secondary electron emitters of the MPG. The distance between electrodes and the resonant frequency of the MPG can be adjusted separately by step motors. The parameter of the accelerator tube was optimized using numerical simulation with the design outlet energy of the electron is 5MeV and an average current of 100mA.

TUPP008	An Automatic Control System for Conditioning 30 GHz Accelerating Structures	controls, vacuum, target, feedback	1541
	A. Dubrovsky, J. A. Rodriguez CERN, Geneva
	A software application programme has been developed to allow fast, automatic, conditioning of the accelerating structures to be high-gradient tested at 30 GHz in CTF3. The specificity of the application is the ability to control a high power electron beam which produces the 30 GHz RF power used to condition the accelerating structures. It significantly increases the amount of time useable for high power conditioning. In this paper this fast control system, the machine control system, the logging system, the graphic user control interface and the logging data visualization are described. An outline of the conditioning control system itself and of the feedback controlling peak power and pulse length is given. The software allows different types of conditioning strategies to be programmed.

TUPP034	Transverse Effects due to Vacuum Mirror of RF Gun	emittance, simulation, vacuum, laser	1613
	I. Zagorodnov, M. Dohlus, M. Krasilnikov DESY, Hamburg E. Gjonaj, S. Schnepp TEMF, Darmstadt
	The transverse kick due to the vacuum mirror in the RF gun can negatively affect the beam emittance. In this contribution we estimate numerically and analytically the transverse wake function of European XFEL RF gun and apply it in beam dynamics studies of the transverse phase space.

TUPP084	Parallel Computation of Integrated Electromagnetic, Thermal and Structural Effects for Accelerator Cavities	simulation, vacuum, emittance, space-charge	1724
	V. Akcelik, A. E. Candel, A. C. Kabel, K. Ko, L. Lee, Z. Li, C.-K. Ng, L. Xiao SLAC, Menlo Park, California
	The successful operation of accelerator cavities has to satisfy both rf and mechanical requirements. It is highly desirable that electromagnetic, thermal and structural effects such as cavity wall heating and Lorentz force detuning in superconducting rf cavities can be addressed in an integrated analysis. Based on the SLAC parallel finite-element code infrastructure for electromagnetic modeling, a novel multi-physics analysis tool has been developed to include additional thermal and mechanical effects. The speedup from parallel computation enables virtual prototyping of accelerator cavities on computers, which would substantially reduce the cost and time of a design cycle. The multi-physics tool will be applied to the LCLS rf gun and a superconducting rf gun cavity.

TUPP112	The RADIOTHOMX Project	electron, laser, photon, linac	1785
	C. Bruni, F. Couchot, Y. Fedala, J. Haissinski, M. Lacroix, R. Roux, V. Variola, Z. F. Zomer LAL, Orsay N. Artemiev LOA, Palaiseau Ph. Balcou, E. Cormier, S. Montant, M. C. Nadeau CELIA, Talence JP. Brasile, A. S. Chauchat, C. Simonboisson THALES, Colombes R. Czarny Thales Laser SA, Orsay P. Gladkikh NSC/KIPT, Kharkov
	The goal of this project is to develop a compact device, which could produce an intense flux of monochromatic X-rays for medical applications. It is based on Compton back-scattering resulting from collisions between laser pulses and relativistic electron bunches. Intense laser beams can be obtained with a high gain Fabry-Perot cavity coupled with a high average power fiber laser. Such a scheme is going to be developed by CELIA and LAL laboratories. The accelerator design to produce high repetition rate electron bunches at 50 MeV is under study. Two possibilities are being investigated: either a linear accelerator combined with a storage ring operating at an injection frequency high enough to preserve the electron beam characteristics or a high average current ERL. Both accelerator configurations aiming at producing X-ray fluxes higher than 10¹² photons/s will be presented.

TUPP121	Spatial Resolution and Contrast of the Intensity Modulated Electron Beam by the Photocathode RF Gun for the Radiation Therapy	electron, laser, radiation, cathode	1809
	T. Kondoh, K. Kan, H. Kashima, K. Norizawa, A. Ogata, S. Tagawa, J. Yang, Y. Yoshida ISIR, Osaka
	The radiation therapy of cancer is developing to un-uniform irradiation as the Intensity Modulated Radiation Therapy (IMRT), for reduce dose to normal tissue. Toward the IMRT, optical modulation of electron beam is studying by a photocathode RF gun. The photocathode RF gun can generate a low emittance electron beam by laser light. Because of the low emittance beam, the modulated electron beam is able to accelerate keeping shape. Electron beam were monitored by CCD cameras measuring the luminescence of the scintillator. Fundamental data such as the spatial resolution and the contrast of the optical intensity modulated electron beam are necessary. Spatial Resolution and Contrast of the Intensity Modulated Electron Beam by a Photocathode RF Gun will be reported. If the shape of the modulated electron beam is different, it may not keep beam shape from the non-symmetrically of the repulsion of the bunch inside. It will be reported that the relations of the beam-shape and the keeping ability of beam.

TUPP157	Commissioning of L-band Electron Accelerator for Industrial Applications	electron, klystron, bunching, power-supply	1875
	S. H. Kim, M.-H. Cho, W. Namkung, H. R. Yang POSTECH, Pohang, Kyungbuk J. Jang, S. D. Jang, S. J. Kwon, J.-S. Oh, S. J. Park, Y. G. Son PAL, Pohang, Kyungbuk
	An intense L-band electron linear accelerator is under construction at CESC (Cheorwon Electron-beam Service Center) for industrial applications. It is capable of producing 10-MeV electron beams with a 30-kW average beam power. For high-power capability, we adopted 1.3 GHz, and the RF source is a 25-MW pulsed klystron with a 60-kW average RF output power. A pre-buncher is used before the bunching section, which is built-in with the regular accelerating sections. The accelerating structure is a disk-loaded waveguide with a constant-impedance operated in the 2π/3-mode. It is to be operated under the fully beam-loaded condition for high average power with the 6-μs pulse length and the 350-Hz repetition rate. In this paper, we present details of the accelerator system and commissioning results.

TUPP158	Development of Laser System for Compact Laser Compton Scattering X-ray Source	laser, electron, scattering, linac	1878
	R. Kuroda, M. K. Koike, H. Toyokawa, K. Y. Yamada AIST, Tsukuba, Ibaraki T. Gowa, A. Masuda, K. Sakaue, M. Washio RISE, Tokyo S. Kashiwagi ISIR, Osaka T. Nakajyo, F. Sakai SHI, Tokyo
	A compact X-ray source via laser Compton scattering is required for biological, medical and industrial science because it has many benefits about generated X-rays such as short pulse, quasi-monochromatic, energy tunability and good directivity. Our X-ray source is conventionally the single collision system between an electron pulse and a laser pulse. To increase X-ray yield, we have developed a multi-collision system with a multi-bunch electron beam and a laser optical cavity. The multi-bunch beam will be generated from a Cs-Te photocathode rf gun sytem using a multi-pulse UV laser system. The laser optical cavity will be built like the regenerative amplification including the collision point between the electron pulse and the laser pulse to enhance the laser peak power per 1 collision on laser Compton scattering. In this conference, we will describe the results of preliminary experiments for the multi-collision system and future plans.

TUPP161	60 keV 30 kW Electron Beam Facility for Electron Beam Technology	electron, controls, cathode, focusing	1887
	Yu. I. Semenov, V. E. Akimov, M. A. Batazova, B. A. Dovzhenko, V. V. Ershov, A. R. Frolov, I. A. Gusev, Ye. A. Gusev, V. M. Konstantinov, N. Kh. Kot, V. R. Kozak, E. A. Kuper, G. I. Kuznetsov, P. V. Logatchev, V. R. Mamkin, A. S. Medvedko, I. V. Nikolaev, A. Yu. Protopopov, D. N. Pureskin, V. V. Repkov, A. N. Selivanov, D. V. Senkov, A. S. Tsyganov, A. A. Zharikov BINP SB RAS, Novosibirsk
	At the Budker Institute of Nuclear Physics, Novosibirsk, the 60 keV 30 kW electron beam facility for electron beam technology has been developed. The electron gun provides continuous or modulated beam within the current range from 1 mA up to 500 mA. The optical system allows both static and dynamic focusing of the electron beam within the 50/500 mm range of distance from the gun outlet, the beam scanning and its parallel displacement from the optical axis. The electron gun facility is controlled by the computer via the CAN interface. This paper presents the general description of the facility, its block diagram and main parameters.

WEPC015	Baseline Design of HLS Linac Upgrade	linac, klystron, electron, quadrupole	2019
	G. Feng, W. Li, L. Shang, L. Wang, C.-F. Wu, H. Xu, S. C. Zhang USTC/NSRL, Hefei, Anhui
	The existing 200MeV linac of Hefei Light Source (HLS) mainly consists of electron gun, prebuncher, buncher, one 3m S-band linac section, and four 6m S-band linac sections. Energy gain of electron beam at the end of the linac is 200MeV and energy spread is ±0.8%. In order to improve the electron beam quality, An upgrade project is required. Four 80MW klystrons will be used to instead the old ones, which can improve the beam energy stability. This upgrade can also make it possible to increase the linac energy from 200 MeV to 400 MeV without changing the accelerating structure. In the meantime, New operation modes of HLS linac has been found by extensive computer modelling and optimization. Electron beam dynamics simulation from electron gun to the end of linac has been given, which considering space charge effects and wakefields.

WEPC071	Installation and Commissioning of the 100 MeV Preinjector Linac of the New Elettra Injector	booster, linac, klystron, electron	2160
	G. D'Auria, P. Borsi, A. Carniel, P. Delgiusto, O. Ferrando, A. Franceschinis, M. M. Milloch, A. Milocco, F. Pribaz, N. Sodomaco, M. Stefanutti, L. Veljak, D. Wang ELETTRA, Basovizza, Trieste L. Picardi, C. Ronsivalle ENEA C. R. Frascati, Frascati (Roma)
	A new full energy injector has been installed and commissioned at Sincrotrone Trieste, the Italian Synchrotron Light Source Facility in Trieste. It consists of a 100 MeV Preinjector Linac (PL) followed by a 2.5 GeV Booster Synchrotron (BS), that will fill the Elettra Storage Ring (SR) with 2.0 GeV and 2.4 GeV electrons. Here a complete description of the preinjector linac and its characterization in terms of beam parameters will be presented and discussed.

WEPC087	New Preinjector for the ESRF Linac	emittance, simulation, cathode, bunching	2195
	T. P. Perron, B. Ogier, A. Panzarella, E. Plouviez, E. Rabeuf, V. Serriere ESRF, Grenoble
	A new preinjector of the 200 MeV Linac is under manufacture at the ESRF. Two operation modes are foreseen, a short pulse of 1ns-.4nC and a long pulse of 1000ns-10nC. The new triode type thermionic 100 Kev gun has been characterized experimentally. The transverse and longitudinal phase space measurements are compared with simulations. The design and the expected performance of the final set-up which includes vertical deflecting plates, pre-bunching and bunching sections will be presented.

WEPC094	Thermo-Cathode RF Gun for BINP Race-Track Microtron-Recuperator	emittance, cathode, injection, bunching	2213
	V. Volkov, E. Kendjebulatov, S. A. Krutikhin, G. Y. Kurkin, V. M. Petrov, I. K. Sedlyarov, N. Vinokurov BINP SB RAS, Novosibirsk
	In 2007 the thermo-cathode RF gun for the Budker INP energy recovery linac (ERL) was designed. The RF gun is capable to emit the electron bunches with the energy of 300 keV, average current of 100 mA, and repetition frequency of 90 MHz. The new injector is adapted to the existing RF system for beam bunching, accelerating and injecting to the linac of the microtron. Its advantage is the absence of high potential of 300 kV at the control circuits of the cathode; therefore the maintenance is simplified. Also due to the absence of the cathode back bombardment by residual gas ions in the RF cavity, the lifetime of the cathode is increased and the obtaining of the repetition frequency up to 90 MHz becomes feasible. In the paper the main characteristics of the injector, its design and results of beam dynamics calculations with optimised regimes are presented.

WEPP077	The XFEL Laser Heater	laser, undulator, electron, vacuum	2695
	V. G. Ziemann, G. Angelova UU/ISV, Uppsala M. Dohlus, Y. A. Kot DESY, Hamburg
	The high-brilliance photo-cathode gun foreseen for the X-FEL will provide beams with extremely small momentum spread that will make the beam susceptible to micro-bunching instabilities which will spoil SASE operation. It is therefore desirable to increase the momentum spread to a level that prevents these instabilties but still is compatible with SASE operation. The laser heater will achive this by superimposing a transversely polarized laser and the electron beam in a properly tuned undulator, thereby producing a momentum modulation that is smeared out in a dogleg chicane to obtain the desired momentum spread increase. We present the initial design and layout of the laser heater system for the X-FEL in Hamburg.

WEPP078	PHIL: a Test Beam line at LAL	laser, simulation, vacuum, emittance	2698
	R. Roux, M. Bernard, G. Bienvenu, S. Cavalier, M. Jore, B. Leblond, B. M. Mercier, B. Mouton, C. P. Prevost, V. Variola LAL, Orsay
	For 2004, in the framework of a European contract, LAL is in charge of the construction of one photo-injector for the drive beam linac of the CLIC Test Facility 3 at CERN. This contract together with national funds allowed LAL to build a test accelerator with the same photo-injector as for CTF3. The goal is to undergo experiments on advanced RF guns but a part of the beam time will be also shared with users of the electron beam. So far, the construction of this accelerator at LAL was very much delayed because of the legal obligation to upgrade the radiation shielding in agreement with the actual radiation safety thresholds. The required civil engineering is now finished and the installation of the components is under way. We will first present a design of the accelerator and few dynamic simulation results. Finally we will give a status of the accelerator construction up to date.

WEPP083	Development of an X-band Hybrid Dielectric-iris-loaded Accelerator	electron, impedance, longitudinal-dynamics, linac	2713
	X. D. He, S. Dong, G. Feng, Y. J. Pei, C.-F. Wu USTC/NSRL, Hefei, Anhui
	A compact x-band hybrid dielectric-iris-loaded travelling-wave linac with constant impendence structure has been designed. By adjusting the values of and the numbers of cells, the beam energy of 29 MeV, the capture efficiency about 50% and the energy spread about with the beam current being 70 mA and the electric gun voltage being 50KeV are obtained through longitudinal dynamics calculation. The length of accelerator tube is 1.12m . The maximum accelerating gradient is less than 45MV/m. By using electromagnetic code such as MAFIA, the attenuation per unit length of structure , the shunt impedance , the quality factor Q, the group velocity and the phase velocity are got by optimizing the dimensions of the cavities.

WEPP090	Accelerator Design for a 1/2 MW Electron Linac for Rare Isotope Beam Production	linac, electron, klystron, target	2728
	S. R. Koscielniak, F. Ames, I. V. Bylinskii, R. E. Laxdal, M. Marchetto, A. K. Mitra, I. Sekachev, V. A. Verzilov TRIUMF, Vancouver
	TRIUMF, in collaboration with university partners, proposes to construct a megawatt-class electron linear accelerator (linac) as a photo-fission driver for radioactive ion beam production (RIB) for nuclear astrophysics studies and materials science. The design strategy, including upgrade path, for this cost-effective facility is elaborated. The 50 MeV, 10 mA, c.w. linac is based on TESLA/ILC super-conducting radio-frequency (SRF) technology at 1.3 GHz and 2K; and consists of an electron gun, buncher and capture sections, followed by 10 MeV and 40 MeV cryomodules containing one and four 9-cell cavities, respectively. Preliminary results from PARMELA beam dynamics simulations are presented. C. W. operation leads to challenges of large cryogenic heat load, input coupler power handling and beam loss mitigation similar to those encountered in ERL-based light sources. Unlike those sources there is no need for high beam brilliance, and a triode thermionic gun modulated at 1.3 GHz is employed; nor are short bunches required, and so the HOM excitation is modest. Many of the major sub-system components have been identified and where possible existing designs will be adopted.

WEPP092	Tuning of Waveguide to Cavity Coupling Coefficient Beta for a PWT Linac and a Photocathode Gun	coupling, linac, simulation, electromagnetic-fields	2734
	S. Krishnagopal BARC, Mumbai U. Kale, S. Lal, K. K. Pant RRCAT, Indore (M. P.)
	The waveguide to cavity coupling coefficient beta for two types of accelerating structures: a Plane Wave Transformer (PWT) linac and a 1.6 cell photocathode gun has been tuned to obtain critical coupling in both. Analytical calculation of the dimensions of slot required for critical coupling have been done using Gao’s formulation based on Bethe’s theory for hole coupling. While the PWT linac structure, with high inter-cell coupling, shows good agreement between measured and predicted slot dimensions for different values of beta, the agreement is not so good in the photocathode gun on account of poor inter-cell coupling. This paper discusses details of the analytical calculation of slot dimensions for the two structures, their comparison with experimentally measured results, and the procedure adopted for tuning the two structures to critical coupling.

WEPP105	First Operation Results of the Superconducting Photoinjector at ELBE	cathode, laser, electron, diagnostics	2755
	J. Teichert, A. Arnold, A. Buechner, H. Buettig, D. Janssen, M. Justus, U. Lehnert, P. Michel, P. Murcek, R. Schurig, G. Staats, F. Staufenbiel, R. Xiang FZD, Dresden T. Kamps BESSY GmbH, Berlin G. Klemz, I. Will MBI, Berlin A. Matheisen DESY, Hamburg
	In November 2007 the first electron beam was generated from the superconducting RF photo electron gun installed at the ELBE linear accelerator facility. The injector together with a sophisticated laser system and a diagnostic beam line were developed and constructed within a collaboration of BESSY, DESY, MBI and FZD. Delivering a CW beam with up to 1 mA average current, a significant improvement of the beam quality like an increase of the bunch charge up to 1 nC and a reduced transverse emittance will be obtained. After the cool-down of the cryostat the RF properties of the 3½-cell niobium cavity like pass band mode frequencies, unloaded quality factor versus accelerating gradient, Lorentz force detuning, and He pressure influence were measured. The first beam was extracted of a Cu photo cathode using a 262 nm UV laser system with a repetition rate of 100 kHz and about 0.4 W laser power. Later, caesium telluride photo cathodes will be applied. The installed diagnostics allow beam current, energy, energy spread, transverse emittance and bunch length measurements of the beam. The results of these measurements and the operational experiences with the gun will be presented.

WEPP148	Generation of High Gradient Wakefields in Dielectric Loaded Structures	electron, laser, insertion, monitoring	2835
	M. E. Conde, S. P. Antipov, F. J. Franchini, W. Gai, F. Gao, R. Konecny, W. Liu, J. G. Power, Z. M. Yusof ANL, Argonne, Illinois C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio
	Dielectric loaded wakefield structures have potential to be used as high gradient accelerator components. Using the high current drive beam at the Argonne Wakefield Accelerator Facility, we employed cylindrical dielectric loaded wakefield structures to generate accelerating fields of up to 100 MV/m. Short electron bunches (13 ps FWHM) of up to 86 nC are used to drive these fields, either as single bunches or as bunch trains. These recently tested standing-wave structures have a field probe near the outer edge of the dielectric to sample the RF fields generated by the electron bunches. Monitoring of these high intensity RF fields serves to verify the absence of electric breakdown.

THPC038	Beam Dynamic Simulations of the New Polarized Electron Injector of the S-DALINAC	simulation, electron, emittance, linac	3062
	B. Steiner, W. Ackermann, S. S. Franke, W. F.O. Müller, T. Weiland TEMF, Darmstadt R. Barday, C. Eckardt, R. Eichhorn, J. Enders, C. Hessler, Y. Poltoratska, A. Richter, M. Roth TU Darmstadt, Darmstadt
	Aiming at an extension of the experimental possibilities at the Superconducting Darmstadt electron linear accelerator S-DALINAC, a polarized gun is going to be constructed at the moment. The new injector will be able to supply polarized electrons with kinetic energy in the 100 keV range and should add to the present unpolarized thermionic 250 keV source. The design requirements include a polarization degree of at least 80%, a mean current intensity of 60 μA and a 3 GHz cw time structure. The gun part is simulated in CST MAFIA whereas subsequent beam dynamics simulations are performed in V-Code. Initial conditions for the V-Code’s moment approach are extracted from the CST MAFIA simulations. The injector consists of short triplets, an alpha magnet, a Wien filter, a Mott polarimeter, a chopper/prebuncher system and beam diagnostic elements. For the simulations, the 3D electromagnetic fields of the beam line elements are used by means of a Taylor series expansion of variable order. All components except the chopper and a collimator is represented in the simulations. Recent beam dynamic results will be presented.

THPC084	Studies of Electromagnetic Space-charge Fields in RF Photocathode Guns	space-charge, emittance, simulation, cathode	3182
	C. S. Park, M. Hess IUCF, Bloomington, Indiana
	In high-brightness rf photocathode guns, the effects of space-charge can be important. In an effort to accurately simulate the effects of these space-charge fields without the presence of numerical grid dispersion, a Green’s function based code called IRPSS (Indiana Rf Photocathode Source Simulator) was developed. In this paper, we show the results of numerical simulations of the Argonne Wakefield Accelerator photocathode gun using IRPSS, and compare them with the results of an electrostatic based simulation code. In addition, we show how electromagnetic space-charge fields can affect the designs of photocathode gun magnetic focusing schemes, such as emittance compensation. We will also show how a multipole moment method can be effectively utilized to compute the reflections of electromagnetic space-charge fields due to irises in photocathode guns. M. Hess, C. S. Park, and D. Bolton. Phys. Rev. ST Accel. Beams 10, 054201 (2007).

THPC091	Experimental Study of an Intense Relativistic Helical Electron Beam Formed with Interception of the Electrons Reflected from the Magnetic Mirror	electron, cathode, space-charge, radiation	3200
	E. V. Ilyakov, I. S. Kulagin, S. V. Kuzikov, A. S. Shevchenko IAP/RAS, Nizhny Novgorod V. N. Manuilov NNGU, Nizhny Novgorod
	A new method of formation of pulsed intense relativistic helical electron beams (HEBs) for gyroresonant devices has been presented. The method is aimed at the increase of pitch-factor and the reduction of HEB velocity spread and is intended for use in the formation systems of laminar HEBs characterized by low influence of space charge on their parameters. The method is based on the operation of a special diaphragm located at one of minima of trajectories at the beginning of the transportation channel. The diaphragm diameter is chosen so that the electrons with the lowest oscillatory velocities cannot bend round the diaphragm and settle on it. The rest electrons pass by moving in the increasing magnetic field. Then, the electrons with the greatest oscillatory velocities are adiabatically reflected from the magnetic mirror between the electron gun and the transportation channel and settle on the back of the same diaphragm. Reduction of space charge of the reflected electrons has led to the increase of HEB pitch-factor (HEBs have been formed with the record of pitch-factors exceeding 2), while the accumulation of space charge worsens the HEB provoking modulation of formed HEB current.

THPC111	Simulation ofμBunching Instability Regimes in the FLASH Bunch Compressors	bunching, simulation, space-charge, linac	3236
	M. Vogt, T. Limberg DESY, Hamburg D. H. Kuk The University of Texas at Austin, Austin, Texas
	The bunch compression scheme for the European XFEL will operate in a regime in which, at least without additional energy spread introduced by a laser heater, theμbunching effect proposed in the literature may severely degrade the performance of the FEL. However, clear, unambiguous signals of theμbunching effect have not yet been seen neither in simulation nor experiment. The proposedμbunching effect amplifies initial current modulations by interleaved application of longitudinal collective energy kicks and transformations of energy modulation into current modulation in magnetic chicanes. In order to establish a parameter regime for experimental verification ofμbunching at the FLASH VUV-FEL at DESY, we have scanned the relevant part of the parameter space using a linear, quasi-analytic, noise-free gain-model and complemented this with particle tracking simulations. The tracking was performed using interleaved runs of ASTRA for acceleration modules and CSRTrack for the chicanes, automatically linked by the start-to-end simulation tool box Gluetrack.

THPC153	Timing System of the New Elettra Injector	booster, injection, extraction, storage-ring	3351
	S. Bassanese, A. Carniel, R. De Monte, M. Ferianis, G. Gaio ELETTRA, Basovizza, Trieste
	A new timing system has been developed to operate the new injector for the Elettra storage ring. It implements a versatile injection system to support standard and exotic fillings as well as the top-up mode of operation. Based on an in-house developed programmable counter VME board, the system provides all the needed triggers by the pre-injector LINAC, the booster injection, the booster ramping system, the booster extraction, and the SR injection. An overview of the system architecture and functionality is described and the performance of the board is reported. All the trigger signals are distributed to the timing clients by means of optical links.

THPP057	Electron Cooling Experiments at LEIR	electron, ion, injection, controls	3497
	G. Tranquille CERN, Geneva
	The LEIR electron cooler is the first of a new generation of coolers utilising high-perveance variable-density electron beams for the cooling and accumulation of heavy ion beams. It was commissioned at the end of 2005 and has since been routinely used to provide high brightness Pb ion beams required for future LHC ion runs. High perveance, or intensity, is required to rapidly reduce the phase-space dimensions of a newly injected “hot” beam whilst the variable density helps to efficiently cool particles with large betatron oscillations and at the same time improve the lifetime of the cooled stack. In this report we present the results of recent measurements made to check and to better understand the influence of the electron beam size, intensity and density profile on the cooling performance.

THPP058	Progress with Electron Beam System for the Tevatron Electron Lenses	electron, proton, cathode, simulation	3500
	V. Kamerdzhiev, G. F. Kuznetsov, G. W. Saewert, V. D. Shiltsev Fermilab, Batavia, Illinois
	We have developed , built and tested two novel electron guns for the Tevatron and RHIC electron lenses: the first, a gridded gun which generates electron beam profile with smoothed edges and broad flat-top; the second, Gaussian beam profile gun which can be used for generation of the profile with depressed emission in the center. We have also developed a new type of HV modulator for use in TELs. In this articel, we desicribe the guns and the modulator, and present results of the bench tests.

THPP124	Commissioning of the 150 MeV SSRF Linac	controls, linac, electron, bunching	3649
	M. H. Zhao, G. Q. Lin, W. H. Liu, B. L. Wang, J. Q. Zhang, S. P. Zhong, W. M. Zhou SINAP, Shanghai
	The 150 MeV SSRF linac has been integrated and commissioned from late 2006 to middle of 2007. This paper presents the design, installation, commissioning and status of this linac.