IPAC2012 - List of Keywords (gun)

Paper	Title	Other Keywords	Page
MOOAA01	Performance of the Cornell High-Brightness, High-Power Electron Injector	cathode, emittance, laser, electron	20
	B.M. Dunham, A.C. Bartnik, I.V. Bazarov, L. Cultrera, J. Dobbins, C.M. Gulliford, G.H. Hoffstaetter, R.P.K. Kaplan, V.O. Kostroun, Y. Li, M. Liepe, X. Liu, F. Löhl, P. Quigley, D.H. Rice, E.N. Smith, K.W. Smolenski, M. Tigner, V. Veshcherevich, Z. Zhao CLASSE, Ithaca, New York, USA S.S. Karkare, H. Li, J.M. Maxson Cornell University, Ithaca, New York, USA
	Funding: NSF DMR-0807731 The last year has seen significant progress in demonstrating the feasibility of a high current, high brightness photoinjector as required for the Energy Recovery Linac driven X-ray source at Cornell University. Both low emittances (0.4 mm-mrad rms normalized for 100% of the beam at 20 pC per bunch and 0.15 mm-mrad rms core emittance with 70% of the beam, and twice these values at 80 pC per bunch) and high average currents with a good lifetime well in excess of 1000 Coulombs at 5 MeV, 20 mA have been demonstrated. If these beams can be accelerated to 5 GeV without diluting the phase space, it would already provide a beam brightness higher than any existing storage ring. Operational experience, results, and the outlook for the future will be presented.
	Slides MOOAA01 [1.424 MB]

MOOAC02	Status and Plans for a Superconducting RF Accelerator Test Facility at Fermilab	cryomodule, SRF, electron, cryogenics	58
	J.R. Leibfritz, R. Andrews, C.M. Baffes, K. Carlson, B. Chase, M.D. Church, E.R. Harms, A.L. Klebaner, M.J. Kucera, A. Martinez, S. Nagaitsev, L.E. Nobrega, J. Reid, M. Wendt, S.J. Wesseln Fermilab, Batavia, USA P. Piot Northern Illinois University, DeKalb, Illinois, USA
	Funding: Operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy. The Advanced Superconducting Test Acccelerator (ASTA) is being constructed at Fermilab. The existing New Muon Lab (NML) building is being converted for this facility. The accelerator will consist of an electron gun, injector, beam acceleration section consisting of 3 TTF-type or ILC-type cryomodules, multiple downstream beamlines for testing diagnostics and conducting various beam tests, and a high power beam dump. When completed, it is envisioned that this facility will initially be capable of generating a 750 MeV electron beam with ILC beam intensity. An expansion of this facility was recently completed that will provide the capability to upgrade the accelerator to a total beam energy of 1.5 GeV. Two new buildings were also constructed adjacent to the ASTA facility to house a new cryogenic plant and multiple superconducting RF (SRF) cryomodule test stands. In addition to testing accelerator components, this facility will be used to test RF power systems, instrumentation, and control systems for future SRF accelerators such as the ILC and Project-X. This paper describes the current status and overall plans for this facility.
	Slides MOOAC02 [13.423 MB]

MOOBC01	Electron Linac Photo-fission Driver for the Rare Isotope Program at TRIUMF	cryomodule, cavity, TRIUMF, linac	64
	S.R. Koscielniak, F. Ames, R.A. Baartman, I.V. Bylinskii, Y.-C. Chao, D. Dale, R.J. Dawson, A. Koveshnikov, A. Laxdal, R.E. Laxdal, F. Mammarella, L. Merminga, A.K. Mitra, Y.-N. Rao, V.A. Verzilov, D. Yosifov, V. Zvyagintsev TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada D. Karlen Victoria University, Victoria, B.C., Canada
	The TRIUMF Advanced Rare Isotope Laboratory (ARIEL) is funded since 2010 June by federal and BC Provincial governments. In collaboration with the University of Victoria, TRIUMF is proceeding with construction of a new target building, connecting tunnel, rehabilitation of an existing vault to contain the electron linear accelerator, and a cryogenic compressor building. TRIUMF starts construction of a 300 keV thermionic gun, and 10 MeV Injector cryomodule (EINJ) in 2012; the designs being complete. The 25 MeV Accelerator Cryomodule will follow in 2013. TRIUMF is embarking on major equipment purchases and has signed contracts for 4K cryogenic plant and a 290kW CW klystron, and four 1.3 GHz Nb 9-cell cavities from a local Canadian supplier. Moreover, the low energy beam transport is under construction; and detailing of two intra-cryomodule beam transports has just begun. Procurements are anticipated in mid 2012 for (i) the entire facility quadrupole magnets, and (ii) the klystron's 600kW HV power supply.
	Slides MOOBC01 [4.852 MB]

MOPPC019	Secondary Electron Yield Measurements of Fermilab’s Main Injector Vacuum Vessel	electron, vacuum, synchrotron, controls	166
	D.J. Scott, D. Capista, K.L. Duel, R.M. Zwaska Fermilab, Batavia, USA S. Greenwald, W. Hartung, Y. Li, T.P. Moore, M.A. Palmer CLASSE, Ithaca, New York, USA R.E. Kirby, M.T.F. Pivi, L. Wang SLAC, Menlo Park, California, USA
	We discuss the progress made on a new installation in Fermilab’s Main Injector that will help investigate the electron cloud phenomenon by making direct measurements of the secondary electron yield (SEY) of samples irradiated in the accelerator. In the Project X upgrade the Main Injector will have its beam intensity increased by a factor of three compared to current operations. This may result in the beam being subject to instabilities from the electron cloud. Measured SEY values can be used to further constrain simulations and aid our extrapolation to Project X intensities. The SEY test-stand, developed in conjunction with Cornell and SLAC, is capable of measuring the SEY from samples using an incident electron beam when the samples are biased at different voltages. We present the design and manufacture of the test-stand and the results of initial laboratory tests on samples prior to installation.

MOPPC054	Multi-code Modelling of Momentum Collimation in the TRIUMF ARIEL Linac	electron, linac, simulation, TRIUMF	253
	F.W. Jones, Y.-C. Chao, C. Gong TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
	The electron linac component of the TRIUMF-ARIEL facility will provide CW beams of 50-75 MeV and up to 0.5 MW of beam power, with consequent requirements for low-loss operation. One factor in controlling beam quality is the reduction of the low-momentum tail arising from the rf-modulated 300 KV electron gun and initial capture elements prior to acceleration in the 10 MeV Injector linac. To study momentum collimation in the 10 MeV transfer line to the main linac, and its implications for downstream beam characteristics, a simulation model has been constructed using several tracking and optics codes, linked together by scripts and data converters. The model follows the evolution of the beam from the e-gun through the injector cryo-module and the medium energy transfer line where the proposed collimator is located. The components, methods and results of this application are described in detail.

MOPPC066	A Design of Thermionic Electron Gun for Traveling Wave Electron-linac in order to Inject Beam into Booster Synchrotron Accelerator	electron, cathode, simulation, synchrotron	286
	S. Ahmadian, F. AbbasiDavani, F. Ghasemi, M.Sh. Shafiee sbu, Tehran, Iran
	Applying computational codes functioning on the basis of methods such as Finite Integration caused the designing of different parts of an accelerator to be done faster and with more precision. The first step in using new software is the validation of these codes by experimental results, analytic relations or validating them against other codes whose validity has already been proved. This research aims to design an appropriate structure for thermionic electron gun of traveling wave electron-linac to be used to inject beam into synchrotron accelerators. Firstly, a simple structure of an electron gun used in TWT tube was simulated, and the parameters such as current, perveance, waist beam position, waist beam radius, beam radius entering anode aperture, and also the electric potential variation in the anode-cathode distance and the electric field of anode aperture were compared by experimental results and analytic relations. After verifying the software accuracy, a design for an electron gun with energy and current respectively 200 keV, 18 A and also initial beam radius of 8mm and minimum beam radius of 2.4 mm situated at the distance of 67.44mm from the cathode, was presented.

MOPPD006	Commissioning of the 2MeV Electron Cooler for COSY / HESR	electron, high-voltage, solenoid, laser	379
	V. Kamerdzhiev, J. Dietrich FZJ, Jülich, Germany V.N. Bocharov, M.I. Bryzgunov, A.D. Goncharov, V.M. Panasyuk, V.V. Parkhomchuk, V.B. Reva, D.N. Skorobogatov BINP SB RAS, Novosibirsk, Russia
	The new electron cooler for COSY is built at BINP Novosibirsk. Electron beam commissioning is in progress. Installation in COSY and commissioning with proton beam is scheduled for the beginning of 2012. Beam cooling with up to 3 A of electron current at up to 2 MeV is expected to boost the luminosity in the entire energy range of COSY by counteracting the effects caused by dense targets interacting with the circulating beam. Furthermore, the 2 MeV electron cooler can be used for beam cooling at injection energy in the HESR ring in the FAIR project. The electron beam is guided by a solenoidal magnetic field all the way from the electron gun to the collector. A cascade transformer provides power to numerous high voltage sections, short solenoids, and the collector inside a pressure vessel filed with SF6 gas. Commissioning results are reported.

MOPPD016	Status of Proof-of-principle Experiment for Coherent Electron Cooling	electron, ion, wiggler, FEL	400
	I. Pinayev, S.A. Belomestnykh, I. Ben-Zvi, J. Bengtsson, A. Elizarov, A.V. Fedotov, D.M. Gassner, Y. Hao, D. Kayran, V. Litvinenko, G.J. Mahler, W. Meng, T. Roser, B. Sheehy, R. Than, J.E. Tuozzolo, G. Wang, S.D. Webb, V. Yakimenko BNL, Upton, Long Island, New York, USA G.I. Bell, D.L. Bruhwiler, V.H. Ranjbar, B.T. Schwartz Tech-X, Boulder, Colorado, USA A. Hutton, G.A. Krafft, M. Poelker, R.A. Rimmer JLAB, Newport News, Virginia, USA M.A. Kholopov, P. Vobly BINP SB RAS, Novosibirsk, Russia
	Funding: US DOE Office of Science, DE-FC02-07ER41499, DE-FG02-08ER85182; NERSC DOE contract No. DE-AC02-05CH11231. Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron colliders. To verify the concept we conduct proof-of-the-principle experiment at RHIC. In this paper, we describe the current experimental setup to be installed into 2 o’clock RHIC interaction regions. We present current design, status of equipment acquisition and estimates for the expected beam parameters.

MOPPD047	Progress of Surface Plasma H⁻ Ion Source with Saddle RF Antenna Plasma Generator	plasma, ion, ion-source, electron	469
	V.G. Dudnikov, R.P. Johnson Muons, Inc, Batavia, USA S.N. Murray, T.R. Pennisi, C. Piller, M. Santana, M.P. Stockli, R.F. Welton ORNL, Oak Ridge, Tennessee, USA
	Funding: Supported in part by SBIR Grant 4729 · 09SC02690. Progress in development of RF H⁻ surface plasma source (SPS) with saddle (SA) RF antenna which will provide better power efficiency for high pulsed and average current, higher brightness with longer lifetime and higher reliability will be considered. Several versions of new plasma generators with a small Al2O3chamber and different antennas and magnetic field configurations were tested in the SNS small Test Stand. A prototype SA SPS was installed in the Test Stand with a larger, normal-sized SNS AlN chamber that achieved unanalyzed peak currents of up to 67 mA with an apparent efficiency of 1.6 mA/kW. Control experiments with H⁻ beam produced by SNS SPS with internal and external antennas in the similar conditions were conducted. A new version of the RF triggering plasma source (TPS) has been designed and fabricated. A Saddle antenna SPS with water cooling is being fabricated for high duty factor testing

MOPPP005	Feasibility of THz Source Based on Coherent Smith-Purcell Radiation Generated by Femtosecond Electron Bunches in Super-Radiant Regime	radiation, electron, simulation, laser	574
	L.G. Sukhikh, K.P. Artyomov, A. Potylitsyn Tomsk Polytechnic University, Tomsk, Russia A.S. Aryshev, J. Urakawa KEK, Ibaraki, Japan V. Karataev JAI, Egham, Surrey, United Kingdom
	Nowadays there is a big interest to THz radiation that is a promising tool for investigations in material science, in biology, medicine and other fields. THz radiation for users is mostly produced by Light Sources that are big and complex machines. Because of this there are numerous activities in research and development of a compact THz source. One of the trends is based on using different types of radiation generated in coherent regime by short electron bunches. The promising radiation mechanism is coherent Smith-Purcell radiation (CSPR) that has monochromatic angular distribution and that is generated while the bunch travels in a vicinity of a grating. In this report we present simulated characteristics of frequency-locked coherent Smith-Purcell radiation (super-radiant regime) generated by a train of short (hundreds of femtosecond) 10 MeV electron bunches with THz spacing. The simulations are performed for different grating profiles and parameters using existing CSPR models and Particle-in-Cell simulation code. We also discuss the feasibility of the THz source based on CSPR and status of the experiment that is prepared at LUCX facility at KEK after the upgrade.

MOPPP006	Inverse Cherenkov Radiation based on Smith-Purcell Effect	radiation, electron, linac, laser	577
	K. Kan, T. Kondoh, K. Norizawa, A. Ogata, J. Yang, Y. Yoshida ISIR, Osaka, Japan M. Hangyo ILE Osaka, Suita, Japan R. Kuroda, H. Toyokawa AIST, Tsukuba, Ibaraki, Japan
	Inverse Cherenkov radiation based on Smith-Purcell effect using metamaterial was investigated. A metallic grating and picosecond electron bunch of 27 MeV beam energy from a thermionic DC gun and linac were used for the inverse radiation. The frequency spectra in terahertz (THz) range were measured by a Michelson interferometer experimentally. Peaks of discrete component in the spectra shifted continuously according to the radiation angles, e. g. discrete peak changing from 0.117 to 0.085 THz with radiation angle along the electron bunch from 102 to 134 degree (backward) using a 2-mm-period metallic grating. In this presentation, experiment using another electron bunch generated by a photocathode RF gun linac will be reported.

MOPPP018	Construction Status of the Compact ERL	linac, cryomodule, emittance, radiation	607
	S. Sakanaka, H. Kawata, Y. Kobayashi, N. Nakamura KEK, Ibaraki, Japan R. Hajima JAEA, Ibaraki-ken, Japan
	Future synchrotron light source based on a 3-GeV energy recovery linac (ERL) is under proposal at KEK, and we are conducting extensive R&D efforts. To demonstrate reliable operations of key components for the ERL project, as well as to demonstrate the generation of ultra-low emittance beams, we are constructing the Compact ERL (cERL). The cERL will also be used to demonstrate the generation of brilliant gamma-rays that is useful for analyzing radioisotopes. Key components, such as a photocathode DC gun, both cryomodules for the injector and the main linac, rf sources, magnets, and beam instrumentations, are under fabrication. Construction of radiation shielding for the cERL started in December, 2011. We report up-to-date status of the cERL.

MOPPP021	Longitudinal Beam Dynamics at the ALICE Acclerator R&D Facility	booster, linac, simulation, FEL	610
	F. Jackson, D. Angal-Kalinin, S.P. Jamison, J.W. McKenzie, T.T. Ng, Y.M. Saveliev, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	The ALICE facility is an energy recovery test accelerator whose applications include an IR-FEL and THz generation. Of primary importance to the performance of the main ALICE applications is the understanding and control of the longitudinal dynamics, which are less amenable to measurement than the transverse. The longitudinal dynamics of the beam evolve are studied in simulation and experiment in several areas of the machine. Simulations of the low energy injector where space charge and velocity bunching may occur are presented. Path length measurement using time-of-arrival monitors are carried out.

MOPPP022	ALICE: Status, Developments and Scientific Programme	FEL, radiation, acceleration, cryomodule	613
	Y.M. Saveliev STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	ALICE (Accelerators and Lasers In Combined Experiments) is a multifunctional ERL based R&D facility that operates in various regimes, both energy recovery and non energy recovery, depending on the project undertaken (beam energy 10-28MeV, bunch charge 20-100pC, train length from a single bunch to 100us). In early 2012, the DC HV photoinjector gun is expected to begin operation at nominal 350kV and a new cryomodule, a result of a wide international collaboration, will be installed and commissioned on ALICE. The improvements in beam dynamics and the overall beam quality will be discussed in this paper. The overview of the ALICE scientific programme including IR-FEL lasing and its application for scanning near field optical microscopy, generation and applications of coherent broadband THz radiation for life sciences and solid state physics, studies of the first non-scaling FFAG EMMA for which ALICE serves as an injector and accelerator physics research will also be presented.

MOPPP023	Effect of DC Photoinjector Gun Voltage on Beam Dynamics in ALICE ERL	electron, booster, linac, cavity	616
	Y.M. Saveliev, F. Jackson, J.K. Jones, J.W. McKenzie STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	The ALICE ERL employs a DC HV photoelectron gun as an electron source. As with other machines in this class, the electron beam is not always of perfect quality. This is aggravated by that the ALICE gun has been operated so far at lower 230kV voltage compared to the design value of 350kV due to hardware limitations. The “two beams” structure was observed and experimentally investigated and found to be the result of complex processes during initial stages of beam acceleration. The experimental observations and data will be compared with those obtained at a nominal 350kV gun voltage. An investigation of the effect of the DC photogun voltage on longitudinal and transverse beam dynamics will be presented and discussed.

MOPPP028	SRF Photoinjector for Proof-of-principle Experiment of Coherent Electron Cooling at RHIC	electron, SRF, emittance, FEL	622
	D. Kayran, S.A. Belomestnykh, I. Ben-Zvi, J.C. Brutus, X. Liang, G.T. McIntyre, I. Pinayev, B. Sheehy, J. Skaritka, T. Srinivasan-Rao, R. Than, J.E. Tuozzolo, Q. Wu, T. Xin BNL, Upton, Long Island, New York, USA V. Litvinenko, M. Ruiz-Osés Stony Brook University, Stony Brook, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy and by Stony Brook DOE grant DE-SC0005713. Coherent Electron Cooling (CEC) based on FEL amplifier promises to be a very good way to cool protons and ions at high energies. A proof of principle experiment to demonstrate cooling at 40 GeV/u is under construction at BNL. One of possible sources to provide sufficient quality electron beam for this experiment is a SRF photoinjector. In this paper we discuss design and simulated performance of the photoinjector based on existing 112 MHz SRF gun and newly designed single-cavity SRF linac operating at 704 MHz.

MOPPP029	Photocathodes at FLASH	cathode, electron, photon, laser	625
	S. Lederer, H. Hansen, H.-H. Sahling, S. Schreiber DESY, Hamburg, Germany P. Michelato, L. Monaco, D. Sertore INFN/LASA, Segrate (MI), Italy
	For several years, cesium telluride photocathodes have been successfully used in the photoinjector of the Free-Electron-Laser FLASH at DESY, Germany. They show a high quantum efficiency and long lifetime and produce routinely thousands of bunches per second with a single bunch charge mostly in the range of 0.3 to 1 nC. Recent studies on lifetime, quantum efficiency, dark current, and operating experience is reported. At DESY, a new preparation system has been set-up. First cathodes have been produced and tested.

MOPPP031	A New Injection System for an Electron/Positron Linac	linac, electron, injection, positron	628
	C. Liebig, M. Hüning, M. Schmitz DESY, Hamburg, Germany
	For the Linac II, which supplies the accelerator chain at DESY with electrons and positrons, a new injection system is planned. It is supposed to ensure reliable operation and to avoid the beam loss of about 60% before the positron converter and the associated activation. The main components are a 6 A/100 kV triode gun, buncher and a dispersive section for energy collimation. The output energy is 5 MeV. The new buncher structure is a hybrid of a standing wave and traveling wave structure and allows a compact design and good electron capture. Its main part is a traveling wave structure in 2π/3 mode, to which one capture cell is coupled in π mode. The function of the injector components, the entire injection system and the acceleration in the linac sections were optimized in simulations. In addition, the design is analysed in a test rig before final installation. Test rig and subsequent injector are equipped with extensive diagnostics. Besides the design of the injection system results of simulations and measurements on the test rig will be presented.

MOPPP032	Longitudinal Phase Space Studies at the PITZ Facility	electron, laser, radiation, FEL	631
	M. Mahgoub, J.W. Bähr, H.-J. Grabosch, M. Groß, L. Hakobyan, G. Klemz, G. Kourkafas, M. Krasilnikov, D. Malyutin, A. Oppelt, M. Otevřel, B. Petrosyan, K. Rosbach, F. Stephan, G. Vashchenko DESY Zeuthen, Zeuthen, Germany I.I. Isaev MEPhI, Moscow, Russia Ye. Ivanisenko IERT, Kharkov, Ukraine M. Khojoyan ANSL, Yerevan, Armenia J. Li USTC/NSRL, Hefei, Anhui, People's Republic of China B. Marchetti INFN-Roma II, Roma, Italy D. Richter HZB, Berlin, Germany J. Rönsch-Schulenburg Uni HH, Hamburg, Germany
	Photoinjectors are a cornerstone for short-wavelength Free Electron Lasers (FELs) like FLASH and the European XFEL in Hamburg, Germany. The Photo Injector Test facility at DESY, location Zeuthen (PITZ), was built to develop and optimize such photoinjectors. The PITZ facility is capable of generating long trains of electron bunches, which can be accelerated up to ~25 MeV/c. Studying and optimizing the longitudinal properties of the electron bunch is an important topic at PITZ. A streak system consisting of Silica Aerogel radiators, optical transition radiation (OTR) screens, optical transmission line, and a streak camera is used to study the longitudinal properties with an accuracy of some ps. Due to the high radiation level in the facility, many of the lenses in the optical transmission line have turned brown, reducing the efficiency of the system. Some of the lenses were recovered by baking them up to 180°C. In contrast, few sensitive objective lenses can not be baked, rather they were recovered via exposure to infrared radiation with the proper wave length. An overview of the system, the difficulties, and the modifications needed to overcome the radiation effects are presented.

MOPPP036	Progress in Reducing the Back-bombardment Effect in the ITC-RF gun for t-ACTS Project at Tohoku University	cathode, electron, dipole, simulation	643
	X. Li, H. Hama, F. Hinode, S. Kashiwagi, M. Kawai, T. Muto, K. Nanbu, Y. Tanaka Tohoku University, Research Center for Electron Photon Science, Sendai, Japan F. Miyahara KEK, Ibaraki, Japan
	An ITC (independently tunable cells) thermionic RF gun* has been developed to produce sub-picosecond electron pulses as part of the injector for coherent terahertz radiation at Tohoku University. Both experiments and simulations have shown that the back-bombardment (B.B.) effect on the LaB6 cathode is a serious issue for option. A numerical model has been developed to evaluate the temperature increase of the cathode due to B.B. in which a 2D equation for heat conduction is solved by taking the back-streaming electrons into account. Using this model we have studied the possibility of suppressing the B.B. by employing dipole field and optimization of the cathode radius, compared with experimental data. Other methods and the prospect of the RF gun will also be reported. * H. Hama et al., New J. Phys. 8 (2006) 292

MOPPP038	Optics Design and Layout for the Electron Beam Test Facility at Daresbury Laboratory	quadrupole, beam-transport, laser, emittance	646
	D. Angal-Kalinin, J.W. McKenzie, B.L. Militsyn STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom J.K. Jones Cockcroft Institute, Warrington, Cheshire, United Kingdom
	An Electron Beam Test Facility (EBTF) is being developed at Daresbury Laboratory to provide the beam for industrial applications and as a front end of future light source facility test under consideration. The RF photoinjector will deliver ~6 MeV beam to industrial users* and will serve as an injector for the future light source facility under consideration at Daresbury*. The Photoinjector design in first phase consists of 2.5 cell RF gun (on loan from Strathclyde) to be driven by Ti:S laser. The photo injector design is aimed to deliver bunches with 10-250 pC bunch charge at low transverse emittances and short bunch lengths. The beam transport optics design described in this paper includes a dedicated diagnostics section capable of measuring ultra short and ultra low emittance bunches and transport to two user areas. P. McIntosh, these proceedings. ** J. Clarke, these proceedings.

MOPPP042	Modeling Multi-bunch X-band Photoinjector Challenges	emittance, electron, linac, laser	658
	R.A. Marsh, S.G. Anderson, C.P.J. Barty, D.J. Gibson, F.V. Hartemann 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 developed at LLNL to investigate accelerator optimization for future upgrades to mono-energetic gamma-ray (MEGa-Ray) technology at LLNL. The test station will consist of a 5.5 cell X-band rf photoinjector, single accelerator section, and beam diagnostics. Of critical import to the functioning of the LLNL X-band system with multiple electron bunches is the performance of the photoinjector. In depth modeling of the Mark 1 LLNL/SLAC X-band rf photoinjector performance will be presented addressing important challenges that must be addressed in order to fabricate a multi-bunch Mark 2 photoinjector. Emittance performance is evaluated under different nominal electron bunch parameters using electrostatic codes such as PARMELA. Wake potential is analyzed using electromagnetic time domain simulations using the ACE3P code T3P. Beam-loading effects and low level rf compensation schemes are explored as well, using a semi-analytic formalism and computer algorithm. Plans for multi-bunch experiments and implementation of photoinjector advances for the Mark 2 design will also be discussed.

MOPPP045	Status of the Wisconsin SRF Gun	cavity, cathode, laser, solenoid	661
	R.A. Legg, J. Bisognano, M.J. Bissen, R.A. Bosch, D. Eisert, M.V. Fisher, M.A. Green, K. Jacobs, R.G. Keil, K.J. Kleman, J.G. Kulpin, G.C. Rogers, M.C. Severson UW-Madison/SRC, Madison, Wisconsin, USA D. Yavuz UW-Madison/PD, Madison, Wisconsin, USA
	Funding: The University of Wisconsin SRF electron gun program is supported by DOE Award DE-SC0005264. SRF electron guns hold out the promise of very bright beams for use in electron injectors, particularly for light source applications such as Free Electron Lasers. The University of Wisconsin is midway in a multi-year program to demonstrate a low frequency electron gun based on a quarter wave resonator cavity. The design includes active tuning and a high temperature superconducting solenoid for emittance compensation. We will report on the status of the 4 MeV SRF electron gun, including the cryomodule, the RF power coupler, the main RF power amplifier/low level RF control system, the photocathode laser system, and the diagnostic beamline. Installation is moving forward in a recently renovated experimental vault adjacent to the existing Aladdin synchrotron. First electron beam is expected in the summer 2012.

MOPPP046	RF Gun Photocathode Research at SLAC	cathode, laser, emittance, electron	664
	E.N. Jongewaard, R. Akre, A. Brachmann, W.J. Corbett, S. Gilevich, K. Grouev, P. Hering, P. Krejcik, J.R. Lewandowski, H. Loos, T. M. Montagne, J. Sheppard, P. Stefan, A.E. Vlieks, S.P. Weathersby, F. Zhou SLAC, Menlo Park, California, USA
	Funding: DOE contract DE-AC02-76SF00515. LCLS is presently operating with a third copper photocathode in the original rf gun, with a quantum efficiency (QE) of ~1x10^-4 and projected emittance eNx,y=0.45 μm at 250 pC bunch charge. The spare LCLS gun is installed in the SLAC Accelerator Structure Test Area (ASTA), processed to the design rf gradient of >120 MV/m. As part of a wider photocathode R&D program, a UV laser system and additional gun diagnostics are being installed at ASTA to measure QE, QE lifetime, and electron beam emittance under a variety of operating conditions. The near-term goals are to test and verify the spare photocathode production/installation sequence, including transfer from the final holding chamber to the rf gun. Mid- and longer-term goals include development of a rigorous understanding of plasma and laser-assisted surface conditioning and investigation of new, high-QE photocathode materials. In parallel, an x-ray photoemission spectroscopy station is nearing completion, to analyze Cu photocathode surface chemistry. In this paper we review the status and anticipated operating parameters of ASTA and the spectroscopy test chamber.

MOPPP050	Physics Results of the NSLS-II Linac Front End Test Stand	linac, emittance, simulation, electron	673
	R.P. Fliller, F. Gao, J. Rose, T.V. Shaftan, X. Yang BNL, Upton, Long Island, New York, USA G. Blokesch PPT, Dortmund, Germany C. Piel RI Research Instruments GmbH, Bergisch Gladbach, Germany
	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 is produced by Research Instruments and will be commissioned in the spring of 2012. As part of the procurement, the linac front end consisting of the gun, prebunching cavity, and diagnostics was delivered early to BNL for testing. We designed a short beamline to supplement the Front End diagnostics to characterize the beam. These tests were instrumental in demonstrating the functioning of the gun, pinpointing technical problems at an early project stage and gaining experience with the linac gun by BNL staff prior to commissioning of the full linac. In this report we show the results of the tests, including charge, bunch length, and transverse emittance measurements and compare them with the relevant linac specifications.

MOPPR075	Status of the APEX Beam Diagnostic and First Measurements	laser, diagnostics, cathode, electron	963
	D. Filippetto, M.J. Chin, C.W. Cork, S. De Santis, L.R. Doolittle, W.E. Norum, C. F. Papadopoulos, G.J. Portmann, D.G. Quintas, F. Sannibale, R.P. Wells, M.S. Zolotorev LBNL, Berkeley, California, USA
	The APEX project aims to the construction of a high brightness high repetition rate photo-injector at LBNL. In its first phase a 750 keV electron bunch is produced at a maximum repetition rate of 1 MHz, with an adjustable charge per bunch spanning the pC-to-nC region. A load lock system is foreseen to test different cathodes without the need of breaking the vacuum and the downstream diagnostic is used to characterize the photo-emitted beam brightness. In the initial phase the main effort is directed toward the measurement of photocurrent, dark current, thermal emittance and electron beam kinetic energy. In a successive phase, diagnostic for full 6D phase space characterization of space charge dominated beams will be added to the beamline. We report and discuss the present diagnostic beamline layout, first beam measurements and future upgrades.

TUXB02	Review of ERL Projects at KEK and Around the World	linac, FEL, electron, emittance	1040
	N. Nakamura KEK, Ibaraki, Japan
	Future synchrotron light sources based on energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. The Japanese collaboration team is making efforts for realizing an ERL-based VUV and X-ray source with R&D efforts on super-conducting cavities and the electron gun at KEK and elsewhere. This presentation will describe the developments of the compact ERL project and the outline of the 3-GeV ERL light source project at KEK and also review ERL projects around the world, including potential applications to colliders.
	Slides TUXB02 [25.328 MB]

TUOBC01	Experimental Verification of the CLIC Two-beam Scheme, Status and Outlook	linac, acceleration, target, emittance	1101
	R. Corsini CERN, Geneva, Switzerland
	The feasibility of the CLIC novel scheme of two-beam acceleration was extensively tested in the CTF3 facility over the last few years. In particular, efficient full beam loading acceleration, isochronous ring operation, beam recombination by transverse RF deflectors have been fully proven. 12 GHz RF power production by high-current drive beam is now part of CTF3 routine operation, and two-beam acceleration up to 150 MV/m has been achieved. Drive beam deceleration tests were carried out as well. In this paper we summarize the main results obtained, including the more recent ones. We also outline and discuss the future experimental program, both in CTF3 and in other beam facilities, as well as the path to a possible facility needed in the initial stage of the CLIC project, CLIC0.
	Slides TUOBC01 [9.921 MB]

TUPPC094	Experimental Observations of Large-amplitude Solitary Waves in Electron Beams	space-charge, electron, laser, longitudinal-dynamics	1377
	Y. Mo, B.L. Beaudoin, D.W. Feldman, I. Haber, R.A. Kishek, P.G. O'Shea UMD, College Park, Maryland, USA J.C.T. Thangaraj Fermilab, Batavia, USA
	Funding: Work funded by the US Dept. of Energy Offices of Fusion Energy Sciences and High Energy Physics and Fusion Energy Sciences, and by the Dept. of Defense Office of Naval Research. The longitudinal dynamics of space charge dominated beams plays an important role in particle accelerators and other applications such as heavy ion fusion and free electron lasers (FELs). All beams are space-charge dominated near the source. Furthermore, the longitudinal profile is not necessarily an ideal mathematical function. By means of experiments on the University of Maryland Electron Ring (UMER), we studied how a perturbation to the line charge density could affect the beam propagation. By varying the initial amplitude of the perturbation, we access nonlinear space charge physics. When starting with large-amplitude perturbations, we have observed, for the first time in charged particle beams, solitary waves for which the nonlinear steepening exactly balances the wave dispersion, leading to persistent waves that preserves their shape over a long distance. This paper presents the results of the soliton experiments, including systematic studies of the dependence of the soliton propagation on beam current, perturbation level and width. The data is compared with theory and simulation.

TUPPD019	New Injector for the EMMA ns-FFAG Ring	booster, cavity, linac, emittance	1449
	B.D. Muratori STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	EMMA is the world’s first non-scaling FFAG which has recently demonstrated acceleration in the serpentine channel. At present, the electron beam is injected into EMMA from the ALICE accelerator. However, funding will be re-directed to an Electron Beam Test Facility (EBTF) in the near future, therefore, in order to continue the broad portfolio of planned experiments required to characterize non-scaling FFAGs, it essential to consider an alternative injection scheme. In this paper, we propose re-utilizing a thermionic gun and a 12 MeV linac from the SRS (Synchrotron Radiation Source) at Daresbury Laboratory. The paper looks at how the required EMMA beam properties can be matched with this new set-up and the advantages and disadvantages involved.

TUPPD034	Multi-bunch Beam Generation by Photo-cathode RF Gun for KEK-STF	cavity, laser, cathode, electron	1479
	M. Kuriki, S. Hosoda, H. Iijima HU/AdSM, Higashi-Hiroshima, Japan A. Ayaka Sokendai, Ibaraki, Japan H. Hayano, J. Urakawa, K. Watanabe KEK, Ibaraki, Japan G. Isoyama, R. Kato, K. Kawase ISIR, Osaka, Japan S. Kashiwagi Tohoku University, Research Center for Electron Photon Science, Sendai, Japan K. Sakaue RISE, Tokyo, Japan
	Funding: MEXT, Quantum beam project. KEK-STF is doing R&D of Super-Conducting (SC) accelerator technology for ILC (International Linear Collider), based on 1.3 GHz RF system. For STF and ILC, the pulse length is 1ms and the repetition is 5Hz. We developed a L-band Normal-Conducting RF gun designed by DESY to provide electron beam over such long pulse duration. For NC Photo-cathode RF gun, such high duty and long pulse operation is a challenging task, because the detuning by the heat load of cavity dissipation power is significant. The RF gun provides the electron pulse train to SC accelerator modules which will be operated at 31.5 MV/m gradient. Precise RF control is essential for SC accelerator because the beam loading and input RF power should be well ballanced for a stable operation. The beam test to demonstrate the stable opeation is very important for SC accelerator R&D. The system is also used to demonstrate high-flux quasi-monochromatic X-ray generation by inverse Compton scattering at KEK-STF. The experiment is carried out from April 2012 to November 2012 at KEK-STF. We report the latest status of the multi-bunch generation by the RF gun.

TUPPD035	SuperKEKB Injector Upgrade for High Charge and Low Emittance Electron Beam	emittance, alignment, wakefield, cathode	1482
	M. Yoshida, N. Iida, Y. Ogawa, M. Sato, L. Zang KEK, Ibaraki, Japan
	The design strategy of SuperKEKB is based on the nano-beam scheme. The dynamic aperture decreases due to the very small beta function at the interaction point. Thus the injector upgrade is required to obtain the low emittance and high charge beam corresponding to the short beam life and small injection acceptance. The required beam parameters are 5 nC, 20 mm mrad and 4 nC, 6 mm mrad for the electron and positron respectively. For the electron beam, new photocathode RF-Gun with the focusing electric field was installed. Further the emittance growth in the linac is an important issue for the low emittance injection. We will report the machine study of the RF-Gun and the emittance growth through the linac.

TUPPD054	Research Activities on Photocathodes for HZDR SRF Gun	cathode, SRF, vacuum, electron	1524
	R. Xiang FZD, Dresden, Germany A. Arnold, M. Freitag, P. Michel, P. Murcek, J. Teichert HZDR, Dresden, Germany
	Funding: We acknowledge the support of the European Community-Research Infrastructure Activity (EuCARD, contract number 227579), as well German Federal Ministry of Education and Research grant 05 ES4BR1/8. Since 2005 the photocathode laboratory has been in operation at HZDR. The main goal is to prepare Cs2Te photocathodes for the SRF gun. A vacuum transport system with UHV is used to move the cathodes from preparation lab to accelerator hall. Up to now 31 Cs2Te photocathodes have been deposited and eight of them have been used in the SRF gun. Quantum efficiency of 1% and lifetime of months can be maintained during the gun operation. At the same time activities are directed towards new photocathode materials with high Q.E. for high current electron sources. Cs3Sb and GaN(Cs) photocathodes have been tested as new candidates, and the design of a preparation system for GaAs(Cs, O) is ongoing.

TUPPD057	High Charge Low Emittance RF Gun for SuperKEKB	cathode, emittance, injection, laser	1533
	T. Natsui, Y. Ogawa, M. Yoshida, X. Zhou KEK, Ibaraki, Japan
	We are developing a new RF gun for SuperKEKB. We are upgrading KEKB to SuperKEKB now. 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. Now, we are testing a Disk and Washer (DAW) type RF gun. Its photo cathode material is LaB6. Normally, LaB6 is used as a thermionic cathode, but it is suitable for　long-life photo cathode operation. This gun has a strong focusing field at the cathode and the acceleration field distribution also has a focusing effect. We will obtain 3.2 MeV beam energy with the gun. The design of RF gun and experimental results will be shown.

TUPPD058	Development of an RF Electron Gun for Ultra-Short Bunch Generation	electron, cavity, cathode, simulation	1536
	Y. Koshiba, T. Aoki, K. Sakaue, M. Washio RISE, Tokyo, Japan T. Takatomi, J. Urakawa KEK, Ibaraki, Japan
	At Waseda University, various researches are done using a photocathode rf electron gun with a 1.6 cell cavity. Now we are developing a new rf cavity specialized for producing an ultra-short electron bunch, with the collaboration of High Energy Accelerator Research Organization (KEK). We have used SUPERFISH for designing the new rf cavity and PARMELA for beam tracking. The new rf cavity has an extra cell following the 1.6 cell. The extra cell can chirp the energy of electron bunch so we call it ECC (Energy Chirping Cell). ECC chirp the energy because we shortened the length of iris just before the ECC and also the length of ECC itself. Moreover, electric field in ECC is made to be stronger than others. We have confirmed on PARMELA that ECC rf gun can generate an 100pC electron bunch less than 200fsec with the energy of 4.5MeV at about 2.5m away from the cathode. Such an ultra-short electron bunch enables us to generate a coherent terahertz light using ultra-short electron bunch by synchrotron radiation or transition radiation. In this conference, we would like to introduce the detail of the design of this new ECC rf gun, the present progresses and future prospects.

TUPPD061	High-Power RF Test of an RF-Gun for PAL-XFEL	laser, emittance, electron, injection	1539
	J.H. Hong, J.H. Han, H.-S. Kang, C. Kim, S.H. Kim, C.-K. Min, S.S. Park, S.J. Park, Y.J. Park PAL, Pohang, Kyungbuk, Republic of Korea M.S. Chae, I.S. Ko, Y.W. Parc POSTECH, Pohang, Kyungbuk, Republic of Korea
	A photocathode RF-gun for the X-ray free electron laser (XFEL) at the Pohang Accelerator Laboratory (PAL) has been fabricated and tested at PAL. This RF-gun is based on a 1.6-cell cavity with dual-feed waveguide ports and two pumping ports. The RF gun was designed by PAL and POSTECH. The RF-gun has been successfully tested with a cathode electric field gradient up to 126MV/m at a repetition rate of 30 Hz. This paper reports the recent results on the beam test of the RF-gun with high power RF at the gun test facility. We present and discuss the measurements of the basic beam parameters such as charge, energy, energy spread, and transverse emittance.

TUPPD063	Interpretation of Dark Current Experimental Results in HZB SC RF Gun	cavity, simulation, accelerating-gradient, HOM	1545
	V. Volkov BINP SB RAS, Novosibirsk, Russia R. Barday, T. Kamps, J. Knobloch, A.N. Matveenko, A. Neumann HZB, Berlin, Germany
	Funding: Work supported by Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association VH-NG-636 and HRJRG-214. The experimental dark current measurement results are obtained on HZB SC RF gun. The field emitters are considered to be random defects on the back wall of the cavity. Conducting wires with 1 micron length, blobs of 200 micron diameter and ”tip on tip” combination of them are taken as dark current emitters in the cavity. RF fields were calculated with CLANS program. The dynamic simulation of dark currents from these emitters fit experimental data. The emitter heating power by RF induced current is four orders of magnitude larger than by the field emitted dark current. The RF induced emitter temperature is proportional to ω1/2 which explains the accelerating gradient limit of a cavity like Kilpatrik law. The RF processing by high order modes seems to be promising.

TUPPD064	Cathode Insert Design for SC RF Guns	cathode, cavity, multipactoring, HOM	1548
	V. Volkov BINP SB RAS, Novosibirsk, Russia R. Barday, T. Kamps, J. Knobloch, A.N. Matveenko HZB, Berlin, Germany
	Funding: Work supported by Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Assiciation VH-NG-636 and HRJRG-214. The cathode inserts in superconducting (SC) RF guns are normal conducting devices attached to a SC RF gun cavity. They enable the photocathode replacement and, at the same time, preserve high quality factor and high fields in the RF guns. However, the insert may also limit the gun performance because of multipacting etc. The experience gathered in early designs at Wuppertal [1], and, more recently at BNL [2] and HZDR [3] is taken into account. We consider the design structure of the cathode insert worked out by BINP for 1 cell prototype of SC HZDR RF gun [4]. The detailed electric, mechanic, and thermal calculations of the initial [4] and the upgraded design are presented in this paper. * A. Michalke et al., EPAC'92, p. 1014 (1992). A. Burrill et al., PAC07, p. 2544 (2007). * D. Janssen et al., NIM A507, 314 (2003). **** D. Janssen et al., NIM A445, 408 (2000).

TUPPD065	An Electron Gun Test Stand to Prepare for the MAX IV Project	cathode, injection, coupling, linac	1551
	S. Werin, E. Elafifi, M. Eriksson, D. Kumbaro, F. Lindau, S. Thorin MAX-lab, Lund, Sweden E. Mansten Lund University, Division of Atomic Physics, Lund, Sweden
	The MAX IV facility, currently under construction, will include a 3 GeV linac injector with two RF guns providing beams for the two operations modes: ring injection and the Short Pulse Facility. The ring injection will be done by a thermionic 3 GHz RF gun developing from the current MAX-lab RF gun. The SPF gun will be a laser driven photo cathode 3 GHz RF gun based on the 1.6 cell BNL/SLAC type. The guns will be operated with short (0.7 us) RF pulses from a SLED system. A test stand to fine tune the operation of the two different systems has been assembled at the MAX IV laboratory (former MAX-lab). The experience in RF commissioning and initial measurements of energy, charge and quantum efficiency will be reported and the extension of the test stand for full emittance characterization will be outlined.

TUPPD066	Lifetime Studies of Cs2Te Cathodes at the PHIN RF Photoinjector at CERN	vacuum, cathode, laser, beam-losses	1554
	C. Heßler, E. Chevallay, M. Divall Csatari, S. Döbert, V. Fedosseev CERN, Geneva, Switzerland
	The PHIN photoinjector has been developed to study the feasibility of a photoinjector option for the CLIC (Compact LInear Collider) drive beam as an alternative to the baseline design, using a thermionic gun. The CLIC drive beam requires a high charge of 8.4 nC per bunch in 0.14 ms long trains, with 500 MHz bunch spacing and 50 Hz macro pulse repetition rate, which corresponds to a total charge per macro pulse of 0.59 mC. This means unusually high peak and average currents for photoinjectors and is challenging with respect to the cathode lifetime. In this paper detailed studies of the lifetime of Cs2Te cathodes, produced by the co-evaporation technique, with respect to bunch charge, train length and vacuum level are presented. Furthermore, the impact of the train length and bunch charge on the vacuum level will be discussed and steps to extend the lifetime will be outlined.

TUPPD068	Design of the Production and Measurement of Ultra-Short Electron Bunches from an S-band RF Photoinjector	cavity, dipole, electron, laser	1560
	J.W. McKenzie, D. Angal-Kalinin, J.K. Jones, B.L. Militsyn STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	The Electron Beam Test Facility (EBTF) is planned for installation in late 2012 at Daresbury Laboratory. An S-band RF photoinjector provides ultrashort, low emittance electron bunches up to 6 MeV. A suite of diagnostics has been designed to fully characterise the bunches. A particular focus has been on producing and measuring bunch lengths less than 100 fs. This can be achieved with a multi-cell standing wave S-band transverse deflecting cavity. Operating such a cavity with low energy electrons provides certain challenges which are discussed in this paper with respect to beam dynamic simulations.

TUPPD069	Schottky-Enabled Photoemission and Dark Current Measurements - Toward an Alternate Approach to Fowler-Nordheim Plot Analysis	laser, site, photon, cathode	1563
	E.E. Wisniewski, W. Gai, J.G. Power ANL, Argonne, USA H. Chen, Y.-C. Du, Hua, J.F. Hua, W.-H. Huang, C.-X. Tang, L.X. Yan, Y. You TUB, Beijing, People's Republic of China A. Grudiev, W. Wuensch CERN, Geneva, Switzerland E.E. Wisniewski Illinois Institute of Technology, Chicago, Illinois, USA
	Field-emitted dark current, a major gradient-limiting factor in RF cavities, is usually analyzed via Fowler-Nordheim (FN) plots. Traditionally, field emission is attributed to geometrical perturbations on the bulk surface whose field enhancement factor (beta) and the emitting area (A) can be extracted from the FN plot. Field enhancement factors extracted in this way are typically much too high (1 to 2 orders of magnitude) to be explainable by either the geometric projection model applied to the measured surface roughness or by field enhancement factors extracted from Schottky-enabled photoemission measurements. We compare traditional analysis of FN plots to an alternate approach employing local work function variation. This is illustrated by comparative analysis of recent dark current and Schottky-enabled photoemission data taken at Tsinghua S-band RF gun. We conclude by describing a possible experimental plan for discrimination of variation of local work function vs. local field enhancement.

TUPPD076	Photocathode Studies for the SPEAR3 Injector RF Gun	cathode, linac, laser, klystron	1575
	S. Park, W.J. Corbett, S.M. Gierman, J.R. Maldonado SLAC, Menlo Park, California, USA
	Funding: Work supported by U.S. Department of Energy Contract DE-AC03- 76SF00515 and Office of Basic Energy Sciences, Division of Chemical Sciences. The electron gun for the SPEAR3 injector operates with a warm thermionic dispenser cathode immersed in a 1.5-cell RF structure. At each injection cycle the gun accelerates several thousand electron bunches up to ~3 MeV during a 2.5us rf pulse. The individual bunches are then compressed by an alpha magnet and a traveling-wave chopper selects 3-5 bunches so they don’t cause beam loading to the linac, where the accelerated bunches reach 120 MeV for subsequent capture in a single booster synchrotron bucket. Tests are underway to operate the dispenser cathode as a cold electron photo-emitter driven by an external laser system. Eventually, without the copper, this will enable multi-bunch injections to the Booster and SPEAR3. In parallel, tests are underway to evaluate quantum efficiency and beam emittance for a beam emitted from a CsBr photocathode with ns- and ps-pulses of UV laser light. In this paper we report on both the cold cathode electron gun operation studies for SPEAR3 and the CsBr research aimed at developing advanced cathode materials for future applications.

TUPPD078	A Novel Design of a High Brightness Superconducting RF Photoinjector Gun Cavity	cavity, SRF, cathode, emittance	1581
	F. Marhauser, R. Rodriguez MuPlus, Inc., Newport News, USA Z. Li SLAC, Menlo Park, California, USA
	Funding: Work supported under U.S. DOE Grant Application Number 98802B12-I Next generation electron accelerators for research, medical, defense or industrial use are in need of electron sources operating at high repetition rates of 1 MHz and beyond, with normalized emittance of 1 mm-mrad or less and bunch charges as much as one nC or more. A conceptual layout of a novel superconducting RF photoinjector gun cavity (SRF gun) is proposed, which can provide unprecedented flexibility to vary beam pulse patterns in the MHz regime and beyond at average currents around 1 mA. It does not require an opening in the center of the back wall and avoids the complex cathode exchange system, but still allows an exchange or refurbishment of the cathode. The demountable back plate has the major benefit to clean the cavity cells independently from the back wall carrying a superconductive photocathode. This mitigates risks of cavity contamination and eases fabrication and chemical post-processing to achieve high accelerating fields, a key parameter to guarantee high brightness beams.

TUPPD079	Design of an L-Band RF Photoinjector for the Idaho Accelerator Center 44 MeV Linac	linac, emittance, laser, solenoid	1584
	M. Titberidze, A.W. Hunt, D.P. Wells IAC, Pocatello, IDAHO, USA Y. Kim ISU, Pocatello, Idaho, USA
	At the Idaho Accelerator Center (IAC) of Idaho State University, we have been operating a 44 MeV L-band RF (1300 MHz) linear accelerator (LINAC) for various user applications such as medical isotope production, Laser Compton Scattering (LCS), positron annihilation energy spectroscopy, and photo fission. But the LINAC is not optimized properly to supply high quality electron beam for those experiments due to limitations of an existing 85 kV thermionic DC gun. In the near future, we are planning to use the L-band LINAC for new user applications such as Accelerator Driven subcritical nuclear reactor System (ADS), photon tagging facility, Ultrafast Electron Diffraction (UED) facility, and high power coherent Terahertz light source facility. Therefore, recently, we have been studying a future upgrade of the L-band LINAC with an RF photoinjector using ASTRA code. In this paper, we describe ASTRA simulation results and a new layout of the L-band LINAC, which is based on an L-band 1.5 cell RF photoinjector. Then, we describe its expected performance for two different single bunch charges (1 nC and 5 nC).

TUPPD080	Design of Ultrafast High-Brightness Electron Source	cathode, electron, brightness, laser	1587
	J.H. Park, H. Bluem, J. Rathke, T. Schultheiss, A.M.M. Todd AES, Princeton, New Jersey, USA
	Funding: This work was supported by the U.S. Department of Energy, under Contract No. DE-SC0006210. Generation and preservation of ultrafast electron beams is one of the major challenges in accelerator R&D. Space charge forces play a fundamental role in emittance dilution and bunch lengthening for all high brightness beams. In order to generate and preserve the ultrafast high-brightness electron beam, transverse and longitudinal space charge effects have to be considered. Several approaches to achieving ultra-short bunches have been explored such as velocity bunching and magnetic compression. However, each option suffers drawbacks in achieving a compact ultrafast high-brightness source. We present an alternative scheme to achieve an ultrafast high-brightness electron beam using a radial bunch compression technique in an x-band photocathode RF electron gun. By compensating the path length difference with a curved cathode and using an extremely high acceleration gradient (greater than 200 MV/m), we seek to deliver 100 pC, 100 fsec bunches.

TUPPD081	Development of Carbon NanoTube (CNT) Cathodes at RadiaBeam	cathode, vacuum, high-voltage, electron	1590
	L. Faillace, R.B. Agustsson, S. Boucher, A.Y. Murokh, A.V. Smirnov RadiaBeam, Santa Monica, USA
	RadiaBeam is developing Carbon Nanotube (CNT) cathodes for DC-pulsed and radio frequency (RF) driven electron sources. CNT cathodes, if realized, are capable of producing very high current density with low thermal emittance, due to ambient operating temperature. The initial experimental results of CNT cathodes are presented, including the high-voltage tests, and life time studies. CNT cathodes potential applications in accelerator science and microwave industry are discussed, and near term plans to test the CNT cathodes in the RF environment are presented.

TUPPD082	Simulations of Multipacting in the Cathode Stalk and FPC of 112 MHz Superconducting Electron Gun	electron, cathode, simulation, niobium	1593
	T. Xin, X. Liang Stony Brook University, Stony Brook, USA S.A. Belomestnykh, I. Ben-Zvi, T. Rao, J. Skaritka, E. Wang, Q. Wu BNL, Upton, Long Island, New York, USA X. Chang Far-Tech, Inc., San Diego, California, USA
	Funding: Work is supported at BNL by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. The work at Stony Brook is supported by the US DOE under grant DE-SC0005713. A 112 MHz superconducting quarter-wave resonator electron gun will be used as the injector of the Coherent Electron Cooling (CEC) proof-of-principle experiment at BNL. Furthermore, this electron gun can be used for testing of the performance of various high quantum efficiency photocathodes. In a previous paper, we presented the design of the cathode stalks and a Fundamental Power Coupler (FPC). In this paper we present updated designs of the cathode stalk and FPC. Multipacting in the cathode stalk and FPC was simulated using three different codes, Multipac, CST particle studio and FishPact respectively. All simulation results show no serious multipacting in the cathode stalk structure and FPC.

TUPPP012	Optimization of the Beam Optical Parameters of the Linac-based Terahertz Source FLUTE	laser, space-charge, linac, simulation	1629
	S. Naknaimueang, E. Huttel, A.-S. Müller, M.J. Nasse, R. Rossmanith, M. Schuh, M. Schwarz, P. Wesolowski KIT, Karlsruhe, Germany M.T. Schmelling MPI-K, Heidelberg, Germany
	Funding: Karlsruher Institut für Technologie. FLUTE is a compact accelerator (consisting of a 7 MeV laser gun, a 50 MeV linac, and bunch compressors) under construction at KIT in Karlsruhe for producing coherent THz radiation. The programs ASTRA and CSRtrack were used to optimize the beam parameters. The aim was to minimize the bunch length used in various THz experiments, with bunch charges between 100 pC and 3 nC. It was calculated that the bunch length after compression depends both on the bunch current and the transverse beam size. The transverse beam size depends on the laser spot size at the cathode of the 7 MeV laser gun. Further simulations showed that a larger beam size reduces the efficiency of the compressor. This problem is cured by focusing elements with a focusing strength depending on the space charge after the gun and integrated into the various compressors layouts under study (four magnets, two magnets and quadrupoles, etc.). The results of these calculations are presented in this paper.

TUPPP038	Electron Beam Collimation for the Next Generation Light Source	collimation, undulator, linac, impedance	1695
	C. Steier, P. Emma, H. Nishimura, C. F. Papadopoulos, F. Sannibale LBNL, Berkeley, California, USA
	Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. The Next Generation Light Source will deliver high (MHz) repetition rate electron beams to an array of free electron lasers. Because of the significant average current in such a facility, effective beam collimation is extremely important to minimize radiation damage to undulators, prevent quenches of superconducting cavities, limit dose rates outside of the accelerator tunnel and prevent equipment damage. This paper describes the conceptual design of the collimator system, as well as the results of simulations to test its effectiveness.

TUPPP060	Injector Design for PAL-XFEL Project	laser, emittance, solenoid, cathode	1732
	J.H. Han, M.S. Chae, J.H. Hong, I. Hwang, H.-S. Kang, I.S. Ko, S.J. Park PAL, Pohang, Kyungbuk, Republic of Korea
	Funding: The Ministry of Education, Science and Technology of the Korean Government The PAL-XFEL project has the baseline specification of FEL radiation down to 0.1 nm with a 10 GeV S-band normal conducting linac. To fulfill the requirement of the beam parameter, the S-band photoinjector was designed. Numerical optimizations for nominal and low charge operations are presented.

TUPPP061	Status of the PAL-XFEL Project	undulator, linac, electron, FEL	1735
	J.H. Han, H.-S. Kang, I.S. Ko PAL, Pohang, Kyungbuk, Republic of Korea
	Funding: The Ministry of Education, Science and Technology of the Korean Government PAL-XFEL is designed to generate X-ray radiation in the range of 0.1 and 10 nm for users. The machine consists of a 10 GeV linear accelerator and five undulator beamlines. Electron beams are generated at a low emittance S-band photocathode RF gun and accelerated with an S-band normal conducting linac. Three hard X-ray beamlines will be located at the end of the linac. Electron beams for two soft X-ray beamlines will be switched at a medium energy. The project started in 2011 and the building construction is ongoing. Resent progress of the project and an update of the current progress are presented.

TUPPP070	Next Generation Light Source R&D and Design Studies at LBNL	FEL, linac, electron, laser	1762
	J.N. Corlett, B. Austin, K.M. Baptiste, D.L. Bowring, J.M. Byrd, S. De Santis, P. Denes, R.J. Donahue, L.R. Doolittle, P. Emma, D. Filippetto, G. Huang, T. Koettig, S. Kwiatkowski, D. Li, T.P. Lou, H. Nishimura, H.A. Padmore, C. F. Papadopoulos, G.C. Pappas, G. Penn, M. Placidi, S. Prestemon, D. Prosnitz, J. Qiang, A. Ratti, M.W. Reinsch, D. Robin, F. Sannibale, D. Schlueter, R.W. Schoenlein, J.W. Staples, C. Steier, C. Sun, T. Vecchione, M. Venturini, W. Wan, R.P. Wells, R.B. Wilcox, J.S. Wurtele LBNL, Berkeley, California, USA
	Funding: Work supported by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. LBNL is developing design concepts for a multi-beamline soft x-ray FEL array powered by a superconducting linear accelerator, operating with a high bunch repetition rate of approximately one MHz. The cw superconducting linear accelerator is supplied by an injector based on a high-brightness, high-repetition-rate photocathode electron gun. Electron bunches are distributed from the linac to the array of independently configurable FEL beamlines with nominal bunch rates up to 100 kHz in each FEL, and with even pulse spacing. Individual FELs may be configured for different modes of operation, and each may produce high peak and average brightness x-rays with a flexible pulse format, and with pulse durations ranging from sub-femtoseconds to hundreds of femtoseconds. In this paper we describe conceptual design studies and optimizations. We describe recent developments in the design and performance parameters, and progress in R&D activities.

TUPPR055	Upgrading the CEBAF Injector with a New Booster, Higher Voltage Gun, and Higher Final Energy	booster, cryomodule, coupling, cavity	1945
	R. Kazimi, A. Freyberger, F.E. Hannon, A.S. Hofler, A. Hutton JLAB, Newport News, Virginia, USA
	Funding: Authored by JSA, LLC under U.S. DOE Contract DE-AC05- 06OR23177. The U.S. Govt. retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this for U.S. Govt. purposes. The CEBAF accelerator at Jefferson Lab will be upgraded from 6 GeV to 12 GeV in the next few years. To meet the requirement of the new machine and also to take the opportunity to improve the beam quality, the CEBAF injector will be upgraded with a higher voltage gun, a new booster, and a new accelerating RF module. The CEBAF injector creates and accelerates three beams at different currents simultaneously. The beams are interleaved, each at one third of RF frequency, traveling through the same beam line. The higher voltage gun will lower the space charge effects making it easier to operate at different current with the same setup. The new booster with optimized beam dynamics will complete the bunching process and provides initial acceleration matched to the new gun voltage. Using our latest SRF design, the new booster has significantly lower XY coupling effects that should improve our beam setup and operation for the highly sensitive parity experiments scheduled for the CEBAF’s future. Finally, the new accelerating RF module will roughly double the injector final energy to match the rest of the 12 GeV accelerator. In this paper we will provide more detail about this upgrade.

WEXA02	Development of Electron Coolers in Novosibirsk	electron, ion, acceleration, proton	2068
	V.V. Parkhomchuk BINP SB RAS, Novosibirsk, Russia S. Nagaitsev Fermilab, Batavia, USA
	An electron cooling method was proposed by G. Budker aproximately 50 years ago. Since the first demonstrations of strong cooling in 1972, the Novosibirsk Institute of Nuclear Physics has continued to develop this technique for various machines with increasingly higher energy beams. Recent application of the e-cooling method at LEIR appeared as a crucial application for a high luminosity achieved in lead-lead ion beam collisions at LHC. This talk should describe the fundamental mechanism of strong cooling, describe historical progress at the BINP and present recent results achieved at the LHC. New 2MeV cooler for COSY ring under commissioning just now at BINP.
	Slides WEXA02 [7.872 MB]

WEOAA03	Development of the Beam Halo Monitor in the J-PARC 3-GeV RCS	extraction, injection, electron, beam-losses	2122
	M. Yoshimoto, N. Hayashi, H. Hotchi, M. Kinsho, S.I. Meigo, K. Okabe, P.K. Saha, K. Yamamoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	Transverse beam halo is one of the most important beam parameters due to limit the performance of the high intensity beam accelerator. Therefore the transverse beam halo measurement is required to increase the beam power of the J-PARC 3-GeV RCS. Transverse halo monitors, which are horizontal and vertical scanning aluminum plates type, has been installed in the extraction beam line. But the residual secondary electrons hindered the beam halo diagnostic. Thus we develop the new beam halo monitor with vibrating wire monitor.
	Slides WEOAA03 [6.701 MB]

WEOBA01	Construction Progress of the RHIC Electron Lenses	electron, solenoid, proton, dipole	2125
	W. Fischer, Z. Altinbas, M. Anerella, E.N. Beebe, M. Blaskiewicz, D. Bruno, W.C. Dawson, D.M. Gassner, X. Gu, R.C. Gupta, K. Hamdi, J. Hock, L.T. Hoff, A.K. Jain, R.F. Lambiase, Y. Luo, M. Mapes, A. Marone, T.A. Miller, M.G. Minty, C. Montag, M. Okamura, A.I. Pikin, S.R. Plate, D. Raparia, Y. Tan, C. Theisen, P. Thieberger, J.E. Tuozzolo, P. Wanderer, S.M. White, W. Zhang BNL, Upton, Long Island, New York, USA
	Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH10886 with the U.S. Department of Energy. In polarized proton operation, the RHIC performance is limited by the head-on beam-beam effect. To overcome these limitations two electron lenses are under construction. We give an overview of the progress over the last year. Guns, collectors and the warm electron beam transport solenoids with their associated power supplies have been constructed. The superconducting solenoids that guide the electron beam during the interaction with the proton beam are near completion. A test stand has been set up to verify the performance of gun, collector and some of the instrumentation. The RHIC infrastructure is being prepared for installation, and simulations continue to optimize the performance.
	Slides WEOBA01 [7.672 MB]

WEOAB02	Photocathode R&D at Cornell University	electron, vacuum, emittance, cathode	2137
	L. Cultrera, I.V. Bazarov, J.V. Conway, B.M. Dunham, Y. Hwang, Y. Li, X. Liu, R. Merluzzi, T.P. Moore, K.W. Smolenski CLASSE, Ithaca, New York, USA S.S. Karkare, J.M. Maxson, W.J. Schaff Cornell University, Ithaca, New York, USA
	Funding: This work has been supported by NSF DMR-0807731 and by DOE DE-SC0003965. A wide R&D program is pursued at Cornell University aimed at preparation and characterization of high efficiency photocathodes for the Energy Recovery Linac photoinjector. The currently investigated photoemitters include both positive and negative electron affinity materials such as respectively bi-alkali antimonide and III-V semiconductors activated with Cs and either O or F. Analysis techniques as Scanning Auger Spectroscopy, Low Energy Electron Diffraction, Reflected High Energy Electron Diffraction and work function measurements are used to characterize the surfaces properties of the specimens. Spectral response, photoemission uniformity, electron energy distributions are used to characterize the quality of the photoelectron beam and to relate it to the measured surface properties.
	Slides WEOAB02 [6.934 MB]

WEEPPB004	Status of the APEX Project at LBNL	cathode, cavity, laser, electron	2173
	F. Sannibale, B.J. Bailey, K.M. Baptiste, J.M. Byrd, C.W. Cork, J.N. Corlett, S. De Santis, L.R. Doolittle, J.A. Doyle, P. Emma, J. Feng, D. Filippetto, G. Huang, H. Huang, T.D. Kramasz, S. Kwiatkowski, W.E. Norum, H.A. Padmore, C. F. Papadopoulos, G.C. Pappas, G.J. Portmann, J. Qiang, D.G. Quintas, J.W. Staples, T. Vecchione, M. Venturini, M. Vinco, W. Wan, R.P. Wells, M.S. Zolotorev, F.A. Zucca LBNL, Berkeley, California, USA M. J. Messerly, M.A. Prantil LLNL, Livermore, California, USA C.M. Pogue NPS, Monterey, California, USA
	Funding: This work was 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 is focused on the development of a high-brightness high-repetition rate (MHz-class) electron injector for X-ray FEL applications. The injector is based on a new concept gun, utilizing a normal conducting 186 MHz RF cavity operating in cw mode in conjunction with high quantum efficiency photocathodes capable of delivering the required repetition rates with available laser technology. The APEX activities are staged in 3 main phases. In Phases 0 and I, the gun will be tested at its nominal energy of 750 keV and several different photocathodes are tested at full repetition rate. In Phase II, a pulsed linac will be added for accelerating the beam at several tens of MeV to reduce space charge effects and measure the high-brightness performance of the gun when integrated in an injector scheme. At Phase II energies, the radiation shielding configuration of APEX limits the repetition rate to a maximum of several Hz. Phase 0 is under commissioning, Phase I under installation, and initial activities for Phase II are underway. This paper presents an update on the status of these activities.

WEEPPB007	Initial Testing of the Mark-0 X-band RF Gun at SLAC	solenoid, vacuum, radiation, cathode	2179
	A.E. Vlieks, C. Adolphsen, V.A. Dolgashev, J.R. Lewandowski, C. Limborg-Deprey, S.P. Weathersby SLAC, Menlo Park, California, USA
	A new X band RF Gun (Mark-0) has been assembled, tuned and is being tested in the ASTA facility at SLAC. This gun has been improved from an earlier gun used in Compton-scattering experiments at SLAC by the introduction of a racetrack dual-input coupler to reduce quadrupole fields. Waveguide-to-coupler irises were also redesigned to reduce surface magnetic fields and therefore peak pulse surface heating. Tests of this photocathode gun will allow us to gain early operational experience for beam tests of a new gun with further improvements (Mark-1) being prepared for SLAC’s X-Band Test Accelerator (XTA) program and the LLNL MegaRay program. Results of current testing up to ≈ 200 MV/m peak surface Electric fields will be presented.

WEPPC111	Multipacting Simulation ADN Test Results of BNL 704 MHz SRF Gun	cavity, cathode, SRF, simulation	2480
	W. Xu, S.A. Belomestnykh, I. Ben-Zvi, C. Cullen, H. Hahn, X. Liang, G.T. McIntyre, D. Pate, S.P. Pontieri, C. Schultheiss, T. Seda, T.N. Tallerico, R. Than, R.J. Todd, S.J. Tuozzolo, A. Zaltsman BNL, Upton, Long Island, New York, USA J. Dai SBU, Stony Brook, New York, USA L.R. Hammons Stony Brook University, Stony Brook, USA
	Funding: This work was supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. The BNL 704 MHz SRF gun has a grooved choke joint to support the photo-cathode. Due to the distortion of grooves at the choke joint during the BCP for the choke joint, several multipacting barriers showed up when it was tested with Nb cathode stalk at JLab. We built a setup to use the spare large grain SRF cavity to test and condition the multipacting at BNL with various power sources. The test is carried out with three steps: cavity, cavity with Nb cathode stalk, and cavity with copper cathode stalk. This paper summarizes the results of multipacting simulation, and presents large grain cavity test setup and the test results.

WEPPC114	Design, Simulation and Conditioning of the Fundamental Power Couplers for BNL SRF Gun	simulation, vacuum, SRF, klystron	2489
	W. Xu, Z. Altinbas, S.A. Belomestnykh, I. Ben-Zvi, S. Deonarine, D.M. Gassner, J.P. Jamilkowski, P. Kankiya, D. Kayran, N. Laloudakis, L. Masi, G.T. McIntyre, D. Pate, D. Phillips, T. Seda, A.N. Steszyn, T.N. Tallerico, R.J. Todd, D. Weiss, A. Zaltsman BNL, Upton, Long Island, New York, USA M.D. Cole, G.J. Whitbeck AES, Medford, NY, USA
	Funding: This work was supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. The 704 MHz SRF gun for the BNL Energy Recovery Linac (ERL) prototype uses two fundamental power couplers (FPCs) to deliver up to total 1 MW of CW RF power into the half-cell cavity. To prepare the couplers for high-power RF service and process multipacting, the FPCs should be conditioned prior to installation into the gun cryomodule. A room-temperature test stand was configured for conditioning FPCs in full reflection regime with varied phase of the reflecting wave. The FPCs have been conditioned up to 250 kW in pulse mode and 125 kW in CW mode. The multipacting simulations were carried out with Track3P code developed at SLAC. The simulations matched the experimental results very well. This paper presents the FPC RF and thermal design, multipacting simulations and conditioning of the BNL gun FPCs.

WEPPD047	Sequencer Design of Timing System for the Taiwan Photon Source	injection, controls, booster, EPICS	2621
	C.Y. Wu, Y.-T. Chang, J. Chen, Y.-S. Cheng, P.C. Chiu, K.T. Hsu, K.H. Hu, C.H. Kuo, C.Y. Liao NSRRC, Hsinchu, Taiwan
	The timing system of the Taiwan Photon Source is used to distribute trigger signals and synchronously clocks to all the equipment of the machine which need them. The timing system basically works by sending event codes from one event generator (EVG) through tree structured, bidirectional optical fiber network to many event receivers. To accommodate various operation and injection scenarios of the TPS storage ring and booster synchrotron and LINAC, timing sequencer design and control is crucial. The sequencer (event code) is stored at sequence RAM of the EVG module. In order to manage sequence RAM of EVG, the timing sequence control is considered to use Matlab scripts embedded in the timing master EPICS IOC. The timing sequencer design will be summarized in this paper.

WEPPD056	Ytterbium Fiber Laser System of DAW RF Gun for SuperKEKB	laser, emittance, cavity, luminosity	2648
	X. Zhou, T. Natsui, Y. Ogawa, M. Yoshida KEK, Ibaraki, Japan
	For obtaining higher luminosity in the SuperKEKB, the photocathode DAW-type RF gun for high-current, low-emittance beams will be employed in the injector linac. The electron beams with a charge of 5 nC and a normalized emittance of 10 micrometer are expected generate in the photocathode RF gun by using the laser source with a center wavelength of 260 nm and a pulse width of 30 ps. Fiber laser especially Ytterbium(Yb) fiber have attracted attention as one of the promising practical alternatives to usual solid-state lasers, offering high energy-extraction efficiency, high repetition rate, high output power, low-cost and so on. Introducing the Ytterbium fiber laser system, we have developed a stable laser amplifier system, which could allow steady beam injection into the SuperKEKB rings. The laser system starts with a large mode-area Yb-doped fiber-based amplifier system, which consists of a passively mode-locked femtosecond Yb-fiber oscillator. To obtain the mJ-class pulse energy, a multi-pass solid-state amplifier is employed. Deep UV pulses for the photocathode are generated by using two frequency-doubling stages. High pulse energy and good stability would be expected.

WEPPD069	PLS-II Linac Upgrade	linac, electron, klystron, emittance	2681
	B.-J. Lee, J.Y. Choi, S. Chunjarean, T. Ha, J.Y. Huang, I. Hwang, Y.D. Joo, C. Kim, M. Kim, S.H. Kim, S.J. Kwon, S.H. Nam, S.S. Park, S.J. Park, S. Shin, Y.G. Son PAL, Pohang, Kyungbuk, Republic of Korea
	This paper reports on the recent status of the Pohang Light Source (PLS)-II linac at Pohang Accelerator Laboratory (PAL). From 2009, the linac upgrade has been started increasing its energy from 2.5 GeV to 3 GeV aiming stable top-up mode operation. First, we show that the stability status of the two different types of modulators to meet the top-up condition which requires very stable modulator system in linac. Next, we introduce upgrade status those differ from their PLS (2.5 GeV) such as installation of the dual vacuum systems for the electron gun to replace it immediately, adding important diagnostic tools, and reutilization of the beam analysis system just after pre-injector. Finally we present the electron beam parameters measured by those diagnostic system.

WEPPD082	Characterization of Photocathode Damage during High Current Operation of the Cornell ERL Photoinjector	ion, site, vacuum, linac	2717
	J.M. Maxson, S.S. Karkare Cornell University, Ithaca, New York, USA I.V. Bazarov, S.A. Belomestnykh, L. Cultrera, D.S. Dale, J. Dobbins, B.M. Dunham, K. Finkelstein, R.P.K. Kaplan, V.O. Kostroun, Y. Li, X. Liu, F. Löhl, B. Pichler, P. Quigley, D.H. Rice, K.W. Smolenski, M. Tigner, V. Veshcherevich, Z. Zhao CLASSE, Ithaca, New York, USA
	The Cornell ERL Photoinjector prototype has recently demonstrated successful operation at 20 mA for 8 hours using a bi-alkali photocathode grown on a Si substrate. The photocathode film was grown off center, and remained relatively undamaged; however, upon removal from the gun, the substrate at the gun electrostatic center displayed significant visible damage. Here we will describe not only the parameters of that particular high current run, but a suite of post-operation surface morphology and crystallographic measurements, including X-ray fluorescence, X-ray diffraction, contact profilometry, scanning electron microscopy, performed about the damage site and photocathode film. The data indicate violent topological changes to the substrate surface, as well as significant induced crystallographic strain. Ion back-bombardment is proposed as a possible mechanism for damage, and a simple model for induced crystal strain is proposed (as opposed to ion induced sputtering), and is shown to have good qualitative agreement with the spatial distribution of damage.

WEPPD084	The E-Lens Test Bench for Rhic Beam-Beam Compensation	electron, controls, dipole, cathode	2720
	X. Gu, Z. Altinbas, J.N. Aronson, E.N. Beebe, W. Fischer, D.M. Gassner, K. Hamdi, J. Hock, L.T. Hoff, P. Kankiya, R.F. Lambiase, Y. Luo, M. Mapes, J.-L. Mi, T.A. Miller, C. Montag, S. Nemesure, M. Okamura, R.H. Olsen, A.I. Pikin, D. Raparia, P.J. Rosas, J. Sandberg, Y. Tan, C. Theisen, P. Thieberger, J.E. Tuozzolo, W. Zhang BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. To compensate for the beam-beam effects from the proton-proton interactions at IP6 and IP8 in the Relativistic Heavy Ion Collider (RHIC), we are fabricating two electron lenses that we plan to install at RHIC IR10. Before installing the e-lenses, we are setting-up the e-lens test bench to test the electron gun, collector, GS1 coil, modulator, partial control system, some instrumentation, and the application software. Some e-lens power supplies, the electronics for current measurement will also be qualified on test bench. The test bench also was designed for measuring the properties of the cathode and the profile of the beam. In this paper, we introduce the layout and elements of the e-lens test bench; and we discuss its present status towards the end of this paper.

WEPPP025	A Test-bed for Future Linear Collider Technology: Argonne Wakefield Accelerator Facility (AWA)	wakefield, electron, linac, acceleration	2778
	M.E. Conde, D.S. Doran, W. Gai, R. Konecny, W. Liu, J.G. Power, Z.M. Yusof ANL, Argonne, USA S.P. Antipov, C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA 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. Research at the AWA Facility has been focused on the development of electron beam driven wakefield structures. Accelerating gradients of up to 100 MV/m have been excited in dielectric loaded cylindrical structures operating in the microwave range of frequencies. Several upgrades, presently underway, will enable the facility to explore higher accelerating gradients, and also be able to generate longer RF pulses of higher intensity. The upgraded 75 MeV drive beam will consist of bunch trains of up to 32 bunches spaced by 0.77 ns with up to 100 nC per bunch. The RF pulses generated by the drive bunches are expected to reach GW power levels, establishing accelerating gradients of hundreds of MV/m.

WEPPP030	Experimental Generation of a Double-bunch Electron Beam by Transverse-to-Longitudinal Phase Space Exchange	laser, electron, focusing, cathode	2789
	T.J. Maxwell, P. Piot Northern Illinois University, DeKalb, Illinois, USA A.S. Johnson, A.H. Lumpkin, J. Ruan, Y.-E. Sun, R.M. Thurman-Keup Fermilab, Batavia, USA
	Funding: Supported by Fermi Research Alliance, LLC under U.S. Dept. of Energy Contract No. DE-AC02-07CH11359, and Northern Illinois Univ. under US Dept. of Defense DURIP program Contract N00014-08-1-10⁶⁴. In this paper we demonstrate the generation of a tunable, longitudinal double-pulse electron beam. Experimental results on the generation of electron bunch trains with sub-picosecond structure have been previously reported where an initial transverse electron beam modulation was produced by masking the electron beam directly. Here the initial transverse structure is imparted by masking of the photoinjector drive laser to effectively produce two horizontally offset beams at photoemission in the RF gun. A longitudinal double-pulse modulation is then realized after a transverse-to-longitudinal phase-space exchange beamline. Longitudinal profile tuning is demonstrated by upstream beam focusing in conjunction with downstream monitoring of single-shot electro-optic spectral decoding of coherent transition radiation. Y.-E. Sun et al., Tunable Subpicosecond Electron-Bunch-Train Generation Using a Transverse-To-Longitudinal Phase-Space Exchange Technique, Phys. Rev. Lett. 10⁵, 234801 (2010).

WEPPR031	Injector Beam Dynamics for a High-repetition Rate 4th-generation Light Source	emittance, electron, space-charge, linac	3000
	C. F. Papadopoulos, J.N. Corlett, P. Emma, D. Filippetto, G. Penn, J. Qiang, M.W. Reinsch, F. Sannibale, C. Steier, M. Venturini, R.P. Wells LBNL, Berkeley, California, USA
	Funding: This work was supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231. We report on the beam dynamics studies and optimization methods for a high-repetition (1 MHz) photoinjector based on a VHF normal conducting electron source. The simultaneous goals of beam compression and preservation of 6-dimensional beam brightness have to be achieved in the injector, in order to accommodate a linac driven FEL light source. For this, a parallel, multiobjective optimization algorithm is used. We discuss the relative merits of different injector design points, as well as the constraints imposed on the beam dynamics by technical considerations such as the high repetition rate.

WEPPR041	Design of a Compact Linear Accelerator for the Ultrafast Electron Diffraction Facility	electron, linac, space-charge, emittance	3027
	M. Mamtimin, A.W. Hunt, Y. Kim, D.P. Wells IAC, Pocatello, IDAHO, USA
	Ultrafast Electron Diffraction (UED) is a powerful tool to find 3-dimensional structures and dynamical transitions of chemical or biological samples with a femtosecond-range temporal resolution and an angstrom-range spatial resolution. Due to the columbic field of electrons, UED can provide a higher cross section and a higher time resolution than those of the ultrafast photon diffraction with X-ray Free Electron Lasers (XFELs). In this paper, we describe the design concepts and ASTRA simulation results of a compact linac for an UED facility.

WEPPR088	Modeling and Simulation of Retarding Field Analyzers at CESRTA	electron, dipole, simulation, vacuum	3138
	J.R. Calvey, J.A. Crittenden, G. Dugan, W. Hartung, J. Makita, M.A. Palmer CLASSE, Ithaca, New York, USA M.A. Furman, M. Venturini LBNL, Berkeley, California, USA
	Funding: Work supported by the US National Science Foundation (PHY-0734867 and PHY-1002467), and Department of Energy (DE-FC02-08ER41538). Over the course of the CESRTA program at Cornell, Retarding Field Analyzers (RFAs) have been installed in drift, dipole, quadrupole, and wiggler field regions of the CESR storage ring. RFAs are used to measure the local electron cloud flux on the vacuum chamber wall. Through the use of a retarding grid and segmented collectors, they also provide information on the energy and transverse distribution of the cloud. Understanding these measurements on a quantitative level requires the use of cloud buildup simulation codes, adapted to include a detailed model of the structure of the RFA and its interaction with the cloud. The nature of this interaction depends strongly on the strength of the local magnetic field. We have developed models for RFAs in drift and dipole regions. The drift model has been cross-checked with bench measurements, and we have compared the RFA-adapted cloud buildup simulations with data. These comparisons have then been used to obtain best fit values for the photo-emission and secondary electron emission characteristics of some of the vacuum chamber materials and cloud mitigating coatings employed at CESRTA.

THYA02	Ultracompact Accelerator Technology for a Next-generation Gamma-Ray Source	klystron, laser, electron, photon	3190
	R.A. Marsh, F. Albert, S.G. Anderson, C.P.J. Barty, 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. This presentation will report on the technology choices and progress manufacturing and testing the injector and accelerator of the 250 MeV ultra-compact Compton Scattering X-ray Source under development at LLNL for homeland security applications.
	Slides THYA02 [12.896 MB]

THPPC042	Modified Magnicon for High-Gradient Accelerator R&D	cavity, electron, solenoid, cathode	3377
	S.V. Shchelkunov, Y. Jiang, M.A. LaPointe Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA J.L. Hirshfield Omega-P, Inc., New Haven, USA V.P. Yakovlev Fermilab, Batavia, USA
	Funding: Research supported by the U.S. Department of Energy, Office of High Energy Physics A self-consistent design is described of a modified 34.3 GHz magnicon amplifier with a TE311-mode output cavity, to replace the existing magnicon at Yale Beam Physics Lab Test Facility whose output cavity operates in the TM310 mode. The main goal for the new design is to achieve robust reliable operation. This is expected since tube performance – according to simulations – is largely insensitive to the magnitude of external dc magnetic fields, including imperfections in magnetic field profile; small changes in gun voltage and current; changes in electron beam radial size; and even poorly matched external circuitry. The new tube, as with its predecessor, is a third harmonic amplifier, with drive and deflection gain cavities near 11.424 GHz and output cavity at 34.272 GHz. The design calculations predict stable output of power of 20-27 MW at a 10 Hz repetition rate in pulses up to 1.3 μs long, with a low probability of breakdown in the output cavity because of low electric fields (less than 650 kV/cm).

THPPC043	Cold Test of an L-band, 2-Cell PWT Photoelectron	cavity, simulation, vacuum, electron	3380
	Y. Luo, D. Yu DULY Research Inc., Rancho Palos Verdes, California, USA R. Andrews, T.N. Khabiboulline Fermilab, Batavia, USA
	Funding: DOE SBIR Grant No. DE-FG02-06ER84460 An L-band, 1+2/2-cell PWT gun with a coax coupler has been designed for high vacuum polarized electron source applications by DULY Research Inc. A cold test model was fabricated and is currently undergoing test at Fermilab, where the gun will eventually be hot tested. The aluminum cold test model includes an rf/ vacuum sieve, 2 disks, endplates, 6 supporting rods and a 6” CF flange, clamped together during testing. Fermilab made measurements for the cavity resonant frequency and axial field distribution using bead pull. To measure the resonant frequency of the cavity small diameter probes are placed through the vacuum sieve slot. A larger diameter probe can be used as an active tuner. This paper presents the results of the cold test and compares measurements with simulation results from 3D SLAC code Omega3p. The axial field distributions are in good agreement with each other. Frequency deviation is less than 0.5%, well within the experimental accuracy.

THPPC048	Innovative Low-Energy Ultra-Fast Electron Diffraction (UED) System	electron, cathode, vacuum, high-voltage	3395
	L. Faillace, S. Boucher RadiaBeam, Santa Monica, USA P. Musumeci UCLA, Los Angeles, California, USA
	Funding: Work supported by DOE. RadiaBeam, in collaboration with UCLA, is developing an innovative, inexpensive, low-energy ultra-fast electron diffraction (UED) system which allows us to reconstruct a single ultrafast event with a single pulse of electrons. Time resolved measurement of atomic motion is one of the frontiers of modern science, and advancements in this area will greatly improve our understanding of the basic processes in materials science, chemistry and biology. The high-frequency (GHz), high voltage, phase-locked RF field in the deflector allows temporal resolution as fine as 100 fs. In this paper, we show the complete design of a UED system based on this concept, including an optimized electron gun, a high-resolution RF deflector, and the post-interaction imaging system.

THPPC071	The Use of a Solid State Analog Television Transmitter as a Superconducting Electron Gun Power Amplifier	cavity, electron, controls, LLRF	3452
	J.G. Kulpin, K.J. Kleman UW-Madison/SRC, Madison, Wisconsin, USA R.A. Legg JLAB, Newport News, Virginia, USA
	Funding: The electron gun program is supported by DOE award DE-SC0005264, and the University of Wisconsin, Madison. A solid state analog television transmitter designed for 200 MHz operation is being commissioned as a radio frequency power amplifier on the Wisconsin superconducting electron gun cavity. The amplifier consists of three separate radio frequency power combiner cabinets and one monitor and control cabinet. The transmitter employs rugged field effect transistors built into one kilowatt drawers that are individually hot swappable at maximum continuous power output. The total combined power of the transmitter system is 33 kW at 200 MHz, output through a standard coaxial transmission line. A low level radio frequency system is employed to digitally synthesize the 200 MHz signal and precisely control amplitude and phase.

THPPR044	A New Electron Beam Test Facility (EBTF) at Daresbury Laboratory for Industrial Accelerator System Development	electron, FEL, laser, vacuum	4074
	P.A. McIntosh, D. Angal-Kalinin, S.R. Buckley, J.A. Clarke, A.R. Goulden, C. Hill, S.P. Jamison, J.K. Jones, A. Kalinin, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, T.T. Ng, B.J.A. Shepherd, R.J. Smith, S.L. Smith, N. Thompson, A.E. Wheelhouse STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom N. Bliss, G.P. Diakun, A. Gleeson, T.J. Jones, B.G. Martlew, A.J. Moss, L. Nicholson, M.D. Roper, C.J. White STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
	Recent UK government funding has facilitated the implementation of a unique accelerator test facility which can provide enabling infrastructures targeted for the development and testing of novel and compact accelerator technologies, specifically through partnership with industry and aimed at addressing applications for medicine, health, security, energy and industrial processing. The infrastructure provision on the Daresbury Science and Innovation Campus (DSIC) will permit research into areas of accelerator technologies which have the potential to revolutionise the cost, compactness and efficiency of such systems. The main element of the infrastructure will be a high performance and flexible electron beam injector facility, feeding customised state-of-the-art testing enclosures and associated support infrastructure. The facility operating parameters and implementation status will be described, along with primary areas of commercialised technology development opportunities.

THPPR049	Study on Electron Microbeam Generation for MRT Based on Photo-cathode RF-Gun	electron, cathode, laser, radiation	4086
	Y. Yoshida, K. Sakaue, M. Washio RISE, Tokyo, Japan
	We have been developing an MRT (Microbeam Radiation Therapy) based on Cs-Te photo cathode RF-Gun at Waseda University. MRT is proposed to treat tumor by using array of several micro-meter parallel beams. In this therapy, irradiated normal tissue repairs itself, by contrast, even a non-irradiated tumor tissue dies. In the other words, the microbeam enhances the radiation sensitivity difference between normal and tumor issues. Therefore, MRT is considered one of the most useful tumor therapies in the future. We have generated electron microbeam by tungsten collimator slit and analyzed their dose distribution in air and in the PMMA phantom. We have used radiochromic film called GAFCHROMIC dosimetry film type HD-810 to measure them. We have compared these experimental results with Monte Carlo simulation of the dose distribution using the EGS5 code. In this conference, we would like to report the electron microbeam procedure, optimization of irradiation condition, evaluation of microbeam specifications and future prospects.

THPPR050	Fabrication and High Power RF Test of A C-band 6MeV Standing-wave Linear Accelerating Structure	simulation, coupling, electron, target	4089
	J.H. Shao, H. Chen, H. Zha TUB, Beijing, People's Republic of China
	We have designed a C-band standing-wave bi-periodic on-axis coupled linear accelerating structure for industrial and medical applications [1]. The output electron energy is 6MeV and the pulse current intensity is 100mA. The structure has been fabricated and measured in cold test. The cold test results show a good agreement between the simulation and actual measurement. At present, it’s under high power RF test. In this paper, we illustrate the fabrication, the results of cold test and newly high power RF test.

THPPR058	Pulse Radiolysis using Double-decker Femtosecond Electron Beam from a Photocathode RF Gun	electron, linac, laser, radiation	4106
	K. Kan, T. Kondoh, K. Norizawa, A. Ogata, J. Yang, Y. Yoshida ISIR, Osaka, Japan
	Pulse radiolysis, which utilizes an electron bunch and a probe light (laser), is a powerful tool that can be used for an observation of ultrafast radiation-induced phenomena. The time resolution in pulse radiolysis depends on the electron bunch length, the probe-light width, and the timing jitter between the electron bunch and the probe light. In order to reduce the jitter, double-decker accelerator, in which separated laser was injected on a photocathode RF gun for a generation of synchronized double electron beams, was applied to pulse radiolysis. One electron beam was used as a pump source of a material, e. g. water, and another as a probe light at 800 nm wavelength with Cherenkov radiation.

THPPR066	Racetrack Microtron for Nondestructive Nuclear Material Detection System	linac, electron, acceleration, microtron	4127
	T. Hori, T. Kii, R. Kinjo, H. Ohgaki, M. Omer, H. Zen Kyoto University, Institute for Advanced Energy, Kyoto, Japan I. Daito, R. Hajima, T. Hayakawa, M. Kando, H. Kotaki JAEA, Kyoto, Japan
	A nuclear material detection system using the quasi-monochromatic gamma-ray beam from a laser Compton Backscattering source has been proposed for the container inspection, where nuclear resonance fluorescence method would be employed for the specific isotope identification such as U-235. In the system an electron beam of good quality at about 220 MeV for the laser Compton backscattering is required. One candidate for such the practical use is a racetrack microtron which design is based on the existing 150 MeV microtron at JAEA.

FRXBA01	Overview of Recent Progress on High Repetition Rate, High Brightness Electron Guns	cathode, electron, SRF, brightness	4160
	F. Sannibale LBNL, Berkeley, California, USA
	In the last few years, the formidable results of x-ray light sources based on FELs opened the door to classes of experiments not accessible before. Operating facilities have relatively low repetition rates (~ 10-100 Hz), and the natural step forward consists in the development of FEL light sources capable of extending their rates by orders of magnitude in the MHz regime. Additionally, ERL based x-ray facilities with their promise of outstanding performance also require extremely high, GHz-class repetition rates. The development of such facilities would represent the next revolutionary step in terms of science capability. To operate such light sources, an electron injector capable of MHz/GHz repetition rates and with the brightness required by X-ray FELs or ERLs is required. Such injector presently does not exist. In response to that, many groups around the world are intensively working on different schemes and technologies that show the potential for achieving the desired results. This presentation includes a description of the requirements for such injectors, an overview of the pursued technologies, and a review of the results obtained so far by the groups active in the field.
	Slides FRXBA01 [6.290 MB]

FRXBB01	Femtosecond Electron Guns for Ultrafast Electron Diffraction	electron, emittance, laser, cathode	4170
	J. Yang, K. Kan, T. Kondoh, N. Naruse, K. Tanimura, Y. Yoshida ISIR, Osaka, Japan J. Urakawa KEK, Ibaraki, Japan
	This talk should describe the development of electron guns for producing femtosecond electron pulses with low (<0.1 micron) emittance, for ultrafast electron diffraction. Comparisons should be made between the systems developed by groups in Asia, Europe and America, outlining any similarities and contrasts. The focus should be on the technology for generating, accelerating, and controlling the bunches, but some description of the science applications should also be included. Finally, prospects for future developments should be considered.
	Slides FRXBB01 [7.004 MB]

Paper

Title

Other Keywords

Page

MOOAA01

Performance of the Cornell High-Brightness, High-Power Electron Injector

cathode, emittance, laser, electron

20

B.M. Dunham, A.C. Bartnik, I.V. Bazarov, L. Cultrera, J. Dobbins, C.M. Gulliford, G.H. Hoffstaetter, R.P.K. Kaplan, V.O. Kostroun, Y. Li, M. Liepe, X. Liu, F. Löhl, P. Quigley, D.H. Rice, E.N. Smith, K.W. Smolenski, M. Tigner, V. Veshcherevich, Z. Zhao
CLASSE, Ithaca, New York, USA
S.S. Karkare, H. Li, J.M. Maxson
Cornell University, Ithaca, New York, USA

Funding: NSF DMR-0807731
The last year has seen significant progress in demonstrating the feasibility of a high current, high brightness photoinjector as required for the Energy Recovery Linac driven X-ray source at Cornell University. Both low emittances (0.4 mm-mrad rms normalized for 100% of the beam at 20 pC per bunch and 0.15 mm-mrad rms core emittance with 70% of the beam, and twice these values at 80 pC per bunch) and high average currents with a good lifetime well in excess of 1000 Coulombs at 5 MeV, 20 mA have been demonstrated. If these beams can be accelerated to 5 GeV without diluting the phase space, it would already provide a beam brightness higher than any existing storage ring. Operational experience, results, and the outlook for the future will be presented.

Slides MOOAA01 [1.424 MB]

MOOAC02

Status and Plans for a Superconducting RF Accelerator Test Facility at Fermilab

cryomodule, SRF, electron, cryogenics

58

J.R. Leibfritz, R. Andrews, C.M. Baffes, K. Carlson, B. Chase, M.D. Church, E.R. Harms, A.L. Klebaner, M.J. Kucera, A. Martinez, S. Nagaitsev, L.E. Nobrega, J. Reid, M. Wendt, S.J. Wesseln
Fermilab, Batavia, USA
P. Piot
Northern Illinois University, DeKalb, Illinois, USA

Funding: Operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
The Advanced Superconducting Test Acccelerator (ASTA) is being constructed at Fermilab. The existing New Muon Lab (NML) building is being converted for this facility. The accelerator will consist of an electron gun, injector, beam acceleration section consisting of 3 TTF-type or ILC-type cryomodules, multiple downstream beamlines for testing diagnostics and conducting various beam tests, and a high power beam dump. When completed, it is envisioned that this facility will initially be capable of generating a 750 MeV electron beam with ILC beam intensity. An expansion of this facility was recently completed that will provide the capability to upgrade the accelerator to a total beam energy of 1.5 GeV. Two new buildings were also constructed adjacent to the ASTA facility to house a new cryogenic plant and multiple superconducting RF (SRF) cryomodule test stands. In addition to testing accelerator components, this facility will be used to test RF power systems, instrumentation, and control systems for future SRF accelerators such as the ILC and Project-X. This paper describes the current status and overall plans for this facility.

Slides MOOAC02 [13.423 MB]

MOOBC01

Electron Linac Photo-fission Driver for the Rare Isotope Program at TRIUMF

cryomodule, cavity, TRIUMF, linac

64

S.R. Koscielniak, F. Ames, R.A. Baartman, I.V. Bylinskii, Y.-C. Chao, D. Dale, R.J. Dawson, A. Koveshnikov, A. Laxdal, R.E. Laxdal, F. Mammarella, L. Merminga, A.K. Mitra, Y.-N. Rao, V.A. Verzilov, D. Yosifov, V. Zvyagintsev
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
D. Karlen
Victoria University, Victoria, B.C., Canada

The TRIUMF Advanced Rare Isotope Laboratory (ARIEL) is funded since 2010 June by federal and BC Provincial governments. In collaboration with the University of Victoria, TRIUMF is proceeding with construction of a new target building, connecting tunnel, rehabilitation of an existing vault to contain the electron linear accelerator, and a cryogenic compressor building. TRIUMF starts construction of a 300 keV thermionic gun, and 10 MeV Injector cryomodule (EINJ) in 2012; the designs being complete. The 25 MeV Accelerator Cryomodule will follow in 2013. TRIUMF is embarking on major equipment purchases and has signed contracts for 4K cryogenic plant and a 290kW CW klystron, and four 1.3 GHz Nb 9-cell cavities from a local Canadian supplier. Moreover, the low energy beam transport is under construction; and detailing of two intra-cryomodule beam transports has just begun. Procurements are anticipated in mid 2012 for (i) the entire facility quadrupole magnets, and (ii) the klystron's 600kW HV power supply.

Slides MOOBC01 [4.852 MB]

MOPPC019

Secondary Electron Yield Measurements of Fermilab’s Main Injector Vacuum Vessel

electron, vacuum, synchrotron, controls

166

D.J. Scott, D. Capista, K.L. Duel, R.M. Zwaska
Fermilab, Batavia, USA
S. Greenwald, W. Hartung, Y. Li, T.P. Moore, M.A. Palmer
CLASSE, Ithaca, New York, USA
R.E. Kirby, M.T.F. Pivi, L. Wang
SLAC, Menlo Park, California, USA

We discuss the progress made on a new installation in Fermilab’s Main Injector that will help investigate the electron cloud phenomenon by making direct measurements of the secondary electron yield (SEY) of samples irradiated in the accelerator. In the Project X upgrade the Main Injector will have its beam intensity increased by a factor of three compared to current operations. This may result in the beam being subject to instabilities from the electron cloud. Measured SEY values can be used to further constrain simulations and aid our extrapolation to Project X intensities. The SEY test-stand, developed in conjunction with Cornell and SLAC, is capable of measuring the SEY from samples using an incident electron beam when the samples are biased at different voltages. We present the design and manufacture of the test-stand and the results of initial laboratory tests on samples prior to installation.

MOPPC054

Multi-code Modelling of Momentum Collimation in the TRIUMF ARIEL Linac

electron, linac, simulation, TRIUMF

253

F.W. Jones, Y.-C. Chao, C. Gong
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada

The electron linac component of the TRIUMF-ARIEL facility will provide CW beams of 50-75 MeV and up to 0.5 MW of beam power, with consequent requirements for low-loss operation. One factor in controlling beam quality is the reduction of the low-momentum tail arising from the rf-modulated 300 KV electron gun and initial capture elements prior to acceleration in the 10 MeV Injector linac. To study momentum collimation in the 10 MeV transfer line to the main linac, and its implications for downstream beam characteristics, a simulation model has been constructed using several tracking and optics codes, linked together by scripts and data converters. The model follows the evolution of the beam from the e-gun through the injector cryo-module and the medium energy transfer line where the proposed collimator is located. The components, methods and results of this application are described in detail.

MOPPC066

A Design of Thermionic Electron Gun for Traveling Wave Electron-linac in order to Inject Beam into Booster Synchrotron Accelerator

electron, cathode, simulation, synchrotron

286

S. Ahmadian, F. AbbasiDavani, F. Ghasemi, M.Sh. Shafiee
sbu, Tehran, Iran

Applying computational codes functioning on the basis of methods such as Finite Integration caused the designing of different parts of an accelerator to be done faster and with more precision. The first step in using new software is the validation of these codes by experimental results, analytic relations or validating them against other codes whose validity has already been proved. This research aims to design an appropriate structure for thermionic electron gun of traveling wave electron-linac to be used to inject beam into synchrotron accelerators. Firstly, a simple structure of an electron gun used in TWT tube was simulated, and the parameters such as current, perveance, waist beam position, waist beam radius, beam radius entering anode aperture, and also the electric potential variation in the anode-cathode distance and the electric field of anode aperture were compared by experimental results and analytic relations. After verifying the software accuracy, a design for an electron gun with energy and current respectively 200 keV, 18 A and also initial beam radius of 8mm and minimum beam radius of 2.4 mm situated at the distance of 67.44mm from the cathode, was presented.

MOPPD006

Commissioning of the 2MeV Electron Cooler for COSY / HESR

electron, high-voltage, solenoid, laser

379

V. Kamerdzhiev, J. Dietrich
FZJ, Jülich, Germany
V.N. Bocharov, M.I. Bryzgunov, A.D. Goncharov, V.M. Panasyuk, V.V. Parkhomchuk, V.B. Reva, D.N. Skorobogatov
BINP SB RAS, Novosibirsk, Russia

The new electron cooler for COSY is built at BINP Novosibirsk. Electron beam commissioning is in progress. Installation in COSY and commissioning with proton beam is scheduled for the beginning of 2012. Beam cooling with up to 3 A of electron current at up to 2 MeV is expected to boost the luminosity in the entire energy range of COSY by counteracting the effects caused by dense targets interacting with the circulating beam. Furthermore, the 2 MeV electron cooler can be used for beam cooling at injection energy in the HESR ring in the FAIR project. The electron beam is guided by a solenoidal magnetic field all the way from the electron gun to the collector. A cascade transformer provides power to numerous high voltage sections, short solenoids, and the collector inside a pressure vessel filed with SF6 gas. Commissioning results are reported.

MOPPD016

Status of Proof-of-principle Experiment for Coherent Electron Cooling

electron, ion, wiggler, FEL

400

I. Pinayev, S.A. Belomestnykh, I. Ben-Zvi, J. Bengtsson, A. Elizarov, A.V. Fedotov, D.M. Gassner, Y. Hao, D. Kayran, V. Litvinenko, G.J. Mahler, W. Meng, T. Roser, B. Sheehy, R. Than, J.E. Tuozzolo, G. Wang, S.D. Webb, V. Yakimenko
BNL, Upton, Long Island, New York, USA
G.I. Bell, D.L. Bruhwiler, V.H. Ranjbar, B.T. Schwartz
Tech-X, Boulder, Colorado, USA
A. Hutton, G.A. Krafft, M. Poelker, R.A. Rimmer
JLAB, Newport News, Virginia, USA
M.A. Kholopov, P. Vobly
BINP SB RAS, Novosibirsk, Russia

Funding: US DOE Office of Science, DE-FC02-07ER41499, DE-FG02-08ER85182; NERSC DOE contract No. DE-AC02-05CH11231.
Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron colliders. To verify the concept we conduct proof-of-the-principle experiment at RHIC. In this paper, we describe the current experimental setup to be installed into 2 o’clock RHIC interaction regions. We present current design, status of equipment acquisition and estimates for the expected beam parameters.

MOPPD047

Progress of Surface Plasma H⁻ Ion Source with Saddle RF Antenna Plasma Generator

plasma, ion, ion-source, electron

469

V.G. Dudnikov, R.P. Johnson
Muons, Inc, Batavia, USA
S.N. Murray, T.R. Pennisi, C. Piller, M. Santana, M.P. Stockli, R.F. Welton
ORNL, Oak Ridge, Tennessee, USA

Funding: Supported in part by SBIR Grant 4729 · 09SC02690.
Progress in development of RF H⁻ surface plasma source (SPS) with saddle (SA) RF antenna which will provide better power efficiency for high pulsed and average current, higher brightness with longer lifetime and higher reliability will be considered. Several versions of new plasma generators with a small Al2O3chamber and different antennas and magnetic field configurations were tested in the SNS small Test Stand. A prototype SA SPS was installed in the Test Stand with a larger, normal-sized SNS AlN chamber that achieved unanalyzed peak currents of up to 67 mA with an apparent efficiency of 1.6 mA/kW. Control experiments with H⁻ beam produced by SNS SPS with internal and external antennas in the similar conditions were conducted. A new version of the RF triggering plasma source (TPS) has been designed and fabricated. A Saddle antenna SPS with water cooling is being fabricated for high duty factor testing

MOPPP005

Feasibility of THz Source Based on Coherent Smith-Purcell Radiation Generated by Femtosecond Electron Bunches in Super-Radiant Regime

radiation, electron, simulation, laser

574

L.G. Sukhikh, K.P. Artyomov, A. Potylitsyn
Tomsk Polytechnic University, Tomsk, Russia
A.S. Aryshev, J. Urakawa
KEK, Ibaraki, Japan
V. Karataev
JAI, Egham, Surrey, United Kingdom

Nowadays there is a big interest to THz radiation that is a promising tool for investigations in material science, in biology, medicine and other fields. THz radiation for users is mostly produced by Light Sources that are big and complex machines. Because of this there are numerous activities in research and development of a compact THz source. One of the trends is based on using different types of radiation generated in coherent regime by short electron bunches. The promising radiation mechanism is coherent Smith-Purcell radiation (CSPR) that has monochromatic angular distribution and that is generated while the bunch travels in a vicinity of a grating. In this report we present simulated characteristics of frequency-locked coherent Smith-Purcell radiation (super-radiant regime) generated by a train of short (hundreds of femtosecond) 10 MeV electron bunches with THz spacing. The simulations are performed for different grating profiles and parameters using existing CSPR models and Particle-in-Cell simulation code. We also discuss the feasibility of the THz source based on CSPR and status of the experiment that is prepared at LUCX facility at KEK after the upgrade.

MOPPP006

Inverse Cherenkov Radiation based on Smith-Purcell Effect

radiation, electron, linac, laser

577

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

Inverse Cherenkov radiation based on Smith-Purcell effect using metamaterial was investigated. A metallic grating and picosecond electron bunch of 27 MeV beam energy from a thermionic DC gun and linac were used for the inverse radiation. The frequency spectra in terahertz (THz) range were measured by a Michelson interferometer experimentally. Peaks of discrete component in the spectra shifted continuously according to the radiation angles, e. g. discrete peak changing from 0.117 to 0.085 THz with radiation angle along the electron bunch from 102 to 134 degree (backward) using a 2-mm-period metallic grating. In this presentation, experiment using another electron bunch generated by a photocathode RF gun linac will be reported.

MOPPP018

Construction Status of the Compact ERL

linac, cryomodule, emittance, radiation

607

S. Sakanaka, H. Kawata, Y. Kobayashi, N. Nakamura
KEK, Ibaraki, Japan
R. Hajima
JAEA, Ibaraki-ken, Japan

Future synchrotron light source based on a 3-GeV energy recovery linac (ERL) is under proposal at KEK, and we are conducting extensive R&D efforts. To demonstrate reliable operations of key components for the ERL project, as well as to demonstrate the generation of ultra-low emittance beams, we are constructing the Compact ERL (cERL). The cERL will also be used to demonstrate the generation of brilliant gamma-rays that is useful for analyzing radioisotopes. Key components, such as a photocathode DC gun, both cryomodules for the injector and the main linac, rf sources, magnets, and beam instrumentations, are under fabrication. Construction of radiation shielding for the cERL started in December, 2011. We report up-to-date status of the cERL.

MOPPP021

Longitudinal Beam Dynamics at the ALICE Acclerator R&D Facility

booster, linac, simulation, FEL

610

F. Jackson, D. Angal-Kalinin, S.P. Jamison, J.W. McKenzie, T.T. Ng, Y.M. Saveliev, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The ALICE facility is an energy recovery test accelerator whose applications include an IR-FEL and THz generation. Of primary importance to the performance of the main ALICE applications is the understanding and control of the longitudinal dynamics, which are less amenable to measurement than the transverse. The longitudinal dynamics of the beam evolve are studied in simulation and experiment in several areas of the machine. Simulations of the low energy injector where space charge and velocity bunching may occur are presented. Path length measurement using time-of-arrival monitors are carried out.

MOPPP022

ALICE: Status, Developments and Scientific Programme

FEL, radiation, acceleration, cryomodule

613

Y.M. Saveliev
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

ALICE (Accelerators and Lasers In Combined Experiments) is a multifunctional ERL based R&D facility that operates in various regimes, both energy recovery and non energy recovery, depending on the project undertaken (beam energy 10-28MeV, bunch charge 20-100pC, train length from a single bunch to 100us). In early 2012, the DC HV photoinjector gun is expected to begin operation at nominal 350kV and a new cryomodule, a result of a wide international collaboration, will be installed and commissioned on ALICE. The improvements in beam dynamics and the overall beam quality will be discussed in this paper. The overview of the ALICE scientific programme including IR-FEL lasing and its application for scanning near field optical microscopy, generation and applications of coherent broadband THz radiation for life sciences and solid state physics, studies of the first non-scaling FFAG EMMA for which ALICE serves as an injector and accelerator physics research will also be presented.

MOPPP023

Effect of DC Photoinjector Gun Voltage on Beam Dynamics in ALICE ERL

electron, booster, linac, cavity

616

Y.M. Saveliev, F. Jackson, J.K. Jones, J.W. McKenzie
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The ALICE ERL employs a DC HV photoelectron gun as an electron source. As with other machines in this class, the electron beam is not always of perfect quality. This is aggravated by that the ALICE gun has been operated so far at lower 230kV voltage compared to the design value of 350kV due to hardware limitations. The “two beams” structure was observed and experimentally investigated and found to be the result of complex processes during initial stages of beam acceleration. The experimental observations and data will be compared with those obtained at a nominal 350kV gun voltage. An investigation of the effect of the DC photogun voltage on longitudinal and transverse beam dynamics will be presented and discussed.

MOPPP028

SRF Photoinjector for Proof-of-principle Experiment of Coherent Electron Cooling at RHIC

electron, SRF, emittance, FEL

622

D. Kayran, S.A. Belomestnykh, I. Ben-Zvi, J.C. Brutus, X. Liang, G.T. McIntyre, I. Pinayev, B. Sheehy, J. Skaritka, T. Srinivasan-Rao, R. Than, J.E. Tuozzolo, Q. Wu, T. Xin
BNL, Upton, Long Island, New York, USA
V. Litvinenko, M. Ruiz-Osés
Stony Brook University, Stony Brook, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy and by Stony Brook DOE grant DE-SC0005713.
Coherent Electron Cooling (CEC) based on FEL amplifier promises to be a very good way to cool protons and ions at high energies. A proof of principle experiment to demonstrate cooling at 40 GeV/u is under construction at BNL. One of possible sources to provide sufficient quality electron beam for this experiment is a SRF photoinjector. In this paper we discuss design and simulated performance of the photoinjector based on existing 112 MHz SRF gun and newly designed single-cavity SRF linac operating at 704 MHz.

MOPPP029

Photocathodes at FLASH

cathode, electron, photon, laser

625

S. Lederer, H. Hansen, H.-H. Sahling, S. Schreiber
DESY, Hamburg, Germany
P. Michelato, L. Monaco, D. Sertore
INFN/LASA, Segrate (MI), Italy

For several years, cesium telluride photocathodes have been successfully used in the photoinjector of the Free-Electron-Laser FLASH at DESY, Germany. They show a high quantum efficiency and long lifetime and produce routinely thousands of bunches per second with a single bunch charge mostly in the range of 0.3 to 1 nC. Recent studies on lifetime, quantum efficiency, dark current, and operating experience is reported. At DESY, a new preparation system has been set-up. First cathodes have been produced and tested.

MOPPP031

A New Injection System for an Electron/Positron Linac

linac, electron, injection, positron

628

C. Liebig, M. Hüning, M. Schmitz
DESY, Hamburg, Germany

For the Linac II, which supplies the accelerator chain at DESY with electrons and positrons, a new injection system is planned. It is supposed to ensure reliable operation and to avoid the beam loss of about 60% before the positron converter and the associated activation. The main components are a 6 A/100 kV triode gun, buncher and a dispersive section for energy collimation. The output energy is 5 MeV. The new buncher structure is a hybrid of a standing wave and traveling wave structure and allows a compact design and good electron capture. Its main part is a traveling wave structure in 2π/3 mode, to which one capture cell is coupled in π mode. The function of the injector components, the entire injection system and the acceleration in the linac sections were optimized in simulations. In addition, the design is analysed in a test rig before final installation. Test rig and subsequent injector are equipped with extensive diagnostics. Besides the design of the injection system results of simulations and measurements on the test rig will be presented.

MOPPP032

Longitudinal Phase Space Studies at the PITZ Facility

electron, laser, radiation, FEL

631

M. Mahgoub, J.W. Bähr, H.-J. Grabosch, M. Groß, L. Hakobyan, G. Klemz, G. Kourkafas, M. Krasilnikov, D. Malyutin, A. Oppelt, M. Otevřel, B. Petrosyan, K. Rosbach, F. Stephan, G. Vashchenko
DESY Zeuthen, Zeuthen, Germany
I.I. Isaev
MEPhI, Moscow, Russia
Ye. Ivanisenko
IERT, Kharkov, Ukraine
M. Khojoyan
ANSL, Yerevan, Armenia
J. Li
USTC/NSRL, Hefei, Anhui, People's Republic of China
B. Marchetti
INFN-Roma II, Roma, Italy
D. Richter
HZB, Berlin, Germany
J. Rönsch-Schulenburg
Uni HH, Hamburg, Germany

Photoinjectors are a cornerstone for short-wavelength Free Electron Lasers (FELs) like FLASH and the European XFEL in Hamburg, Germany. The Photo Injector Test facility at DESY, location Zeuthen (PITZ), was built to develop and optimize such photoinjectors. The PITZ facility is capable of generating long trains of electron bunches, which can be accelerated up to ~25 MeV/c. Studying and optimizing the longitudinal properties of the electron bunch is an important topic at PITZ. A streak system consisting of Silica Aerogel radiators, optical transition radiation (OTR) screens, optical transmission line, and a streak camera is used to study the longitudinal properties with an accuracy of some ps. Due to the high radiation level in the facility, many of the lenses in the optical transmission line have turned brown, reducing the efficiency of the system. Some of the lenses were recovered by baking them up to 180°C. In contrast, few sensitive objective lenses can not be baked, rather they were recovered via exposure to infrared radiation with the proper wave length. An overview of the system, the difficulties, and the modifications needed to overcome the radiation effects are presented.

MOPPP036

Progress in Reducing the Back-bombardment Effect in the ITC-RF gun for t-ACTS Project at Tohoku University

cathode, electron, dipole, simulation

643

X. Li, H. Hama, F. Hinode, S. Kashiwagi, M. Kawai, T. Muto, K. Nanbu, Y. Tanaka
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
F. Miyahara
KEK, Ibaraki, Japan

An ITC (independently tunable cells) thermionic RF gun* has been developed to produce sub-picosecond electron pulses as part of the injector for coherent terahertz radiation at Tohoku University. Both experiments and simulations have shown that the back-bombardment (B.B.) effect on the LaB6 cathode is a serious issue for option. A numerical model has been developed to evaluate the temperature increase of the cathode due to B.B. in which a 2D equation for heat conduction is solved by taking the back-streaming electrons into account. Using this model we have studied the possibility of suppressing the B.B. by employing dipole field and optimization of the cathode radius, compared with experimental data. Other methods and the prospect of the RF gun will also be reported.
* H. Hama et al., New J. Phys. 8 (2006) 292

MOPPP038

Optics Design and Layout for the Electron Beam Test Facility at Daresbury Laboratory

quadrupole, beam-transport, laser, emittance

646

D. Angal-Kalinin, J.W. McKenzie, B.L. Militsyn
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
J.K. Jones
Cockcroft Institute, Warrington, Cheshire, United Kingdom

An Electron Beam Test Facility (EBTF) is being developed at Daresbury Laboratory to provide the beam for industrial applications and as a front end of future light source facility test under consideration. The RF photoinjector will deliver ~6 MeV beam to industrial users* and will serve as an injector for the future light source facility under consideration at Daresbury**. The Photoinjector design in first phase consists of 2.5 cell RF gun (on loan from Strathclyde) to be driven by Ti:S laser. The photo injector design is aimed to deliver bunches with 10-250 pC bunch charge at low transverse emittances and short bunch lengths. The beam transport optics design described in this paper includes a dedicated diagnostics section capable of measuring ultra short and ultra low emittance bunches and transport to two user areas.
* P. McIntosh, these proceedings.
** J. Clarke, these proceedings.

MOPPP042

Modeling Multi-bunch X-band Photoinjector Challenges

emittance, electron, linac, laser

658

R.A. Marsh, S.G. Anderson, C.P.J. Barty, D.J. Gibson, F.V. Hartemann
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 developed at LLNL to investigate accelerator optimization for future upgrades to mono-energetic gamma-ray (MEGa-Ray) technology at LLNL. The test station will consist of a 5.5 cell X-band rf photoinjector, single accelerator section, and beam diagnostics. Of critical import to the functioning of the LLNL X-band system with multiple electron bunches is the performance of the photoinjector. In depth modeling of the Mark 1 LLNL/SLAC X-band rf photoinjector performance will be presented addressing important challenges that must be addressed in order to fabricate a multi-bunch Mark 2 photoinjector. Emittance performance is evaluated under different nominal electron bunch parameters using electrostatic codes such as PARMELA. Wake potential is analyzed using electromagnetic time domain simulations using the ACE3P code T3P. Beam-loading effects and low level rf compensation schemes are explored as well, using a semi-analytic formalism and computer algorithm. Plans for multi-bunch experiments and implementation of photoinjector advances for the Mark 2 design will also be discussed.

MOPPP045

Status of the Wisconsin SRF Gun

cavity, cathode, laser, solenoid

661

R.A. Legg, J. Bisognano, M.J. Bissen, R.A. Bosch, D. Eisert, M.V. Fisher, M.A. Green, K. Jacobs, R.G. Keil, K.J. Kleman, J.G. Kulpin, G.C. Rogers, M.C. Severson
UW-Madison/SRC, Madison, Wisconsin, USA
D. Yavuz
UW-Madison/PD, Madison, Wisconsin, USA

Funding: The University of Wisconsin SRF electron gun program is supported by DOE Award DE-SC0005264.
SRF electron guns hold out the promise of very bright beams for use in electron injectors, particularly for light source applications such as Free Electron Lasers. The University of Wisconsin is midway in a multi-year program to demonstrate a low frequency electron gun based on a quarter wave resonator cavity. The design includes active tuning and a high temperature superconducting solenoid for emittance compensation. We will report on the status of the 4 MeV SRF electron gun, including the cryomodule, the RF power coupler, the main RF power amplifier/low level RF control system, the photocathode laser system, and the diagnostic beamline. Installation is moving forward in a recently renovated experimental vault adjacent to the existing Aladdin synchrotron. First electron beam is expected in the summer 2012.

MOPPP046

RF Gun Photocathode Research at SLAC

cathode, laser, emittance, electron

664

E.N. Jongewaard, R. Akre, A. Brachmann, W.J. Corbett, S. Gilevich, K. Grouev, P. Hering, P. Krejcik, J.R. Lewandowski, H. Loos, T. M. Montagne, J. Sheppard, P. Stefan, A.E. Vlieks, S.P. Weathersby, F. Zhou
SLAC, Menlo Park, California, USA

Funding: DOE contract DE-AC02-76SF00515.
LCLS is presently operating with a third copper photocathode in the original rf gun, with a quantum efficiency (QE) of ~1x10^-4 and projected emittance eNx,y=0.45 μm at 250 pC bunch charge. The spare LCLS gun is installed in the SLAC Accelerator Structure Test Area (ASTA), processed to the design rf gradient of >120 MV/m. As part of a wider photocathode R&D program, a UV laser system and additional gun diagnostics are being installed at ASTA to measure QE, QE lifetime, and electron beam emittance under a variety of operating conditions. The near-term goals are to test and verify the spare photocathode production/installation sequence, including transfer from the final holding chamber to the rf gun. Mid- and longer-term goals include development of a rigorous understanding of plasma and laser-assisted surface conditioning and investigation of new, high-QE photocathode materials. In parallel, an x-ray photoemission spectroscopy station is nearing completion, to analyze Cu photocathode surface chemistry. In this paper we review the status and anticipated operating parameters of ASTA and the spectroscopy test chamber.

MOPPP050

Physics Results of the NSLS-II Linac Front End Test Stand

linac, emittance, simulation, electron

673

R.P. Fliller, F. Gao, J. Rose, T.V. Shaftan, X. Yang
BNL, Upton, Long Island, New York, USA
G. Blokesch
PPT, Dortmund, Germany
C. Piel
RI Research Instruments GmbH, Bergisch Gladbach, Germany

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 is produced by Research Instruments and will be commissioned in the spring of 2012. As part of the procurement, the linac front end consisting of the gun, prebunching cavity, and diagnostics was delivered early to BNL for testing. We designed a short beamline to supplement the Front End diagnostics to characterize the beam. These tests were instrumental in demonstrating the functioning of the gun, pinpointing technical problems at an early project stage and gaining experience with the linac gun by BNL staff prior to commissioning of the full linac. In this report we show the results of the tests, including charge, bunch length, and transverse emittance measurements and compare them with the relevant linac specifications.

MOPPR075

Status of the APEX Beam Diagnostic and First Measurements

laser, diagnostics, cathode, electron

963

D. Filippetto, M.J. Chin, C.W. Cork, S. De Santis, L.R. Doolittle, W.E. Norum, C. F. Papadopoulos, G.J. Portmann, D.G. Quintas, F. Sannibale, R.P. Wells, M.S. Zolotorev
LBNL, Berkeley, California, USA

The APEX project aims to the construction of a high brightness high repetition rate photo-injector at LBNL. In its first phase a 750 keV electron bunch is produced at a maximum repetition rate of 1 MHz, with an adjustable charge per bunch spanning the pC-to-nC region. A load lock system is foreseen to test different cathodes without the need of breaking the vacuum and the downstream diagnostic is used to characterize the photo-emitted beam brightness. In the initial phase the main effort is directed toward the measurement of photocurrent, dark current, thermal emittance and electron beam kinetic energy. In a successive phase, diagnostic for full 6D phase space characterization of space charge dominated beams will be added to the beamline. We report and discuss the present diagnostic beamline layout, first beam measurements and future upgrades.

TUXB02

Review of ERL Projects at KEK and Around the World

linac, FEL, electron, emittance

1040

N. Nakamura
KEK, Ibaraki, Japan

Future synchrotron light sources based on energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. The Japanese collaboration team is making efforts for realizing an ERL-based VUV and X-ray source with R&D efforts on super-conducting cavities and the electron gun at KEK and elsewhere. This presentation will describe the developments of the compact ERL project and the outline of the 3-GeV ERL light source project at KEK and also review ERL projects around the world, including potential applications to colliders.

Slides TUXB02 [25.328 MB]

TUOBC01

Experimental Verification of the CLIC Two-beam Scheme, Status and Outlook

linac, acceleration, target, emittance

1101

R. Corsini
CERN, Geneva, Switzerland

The feasibility of the CLIC novel scheme of two-beam acceleration was extensively tested in the CTF3 facility over the last few years. In particular, efficient full beam loading acceleration, isochronous ring operation, beam recombination by transverse RF deflectors have been fully proven. 12 GHz RF power production by high-current drive beam is now part of CTF3 routine operation, and two-beam acceleration up to 150 MV/m has been achieved. Drive beam deceleration tests were carried out as well. In this paper we summarize the main results obtained, including the more recent ones. We also outline and discuss the future experimental program, both in CTF3 and in other beam facilities, as well as the path to a possible facility needed in the initial stage of the CLIC project, CLIC0.

Slides TUOBC01 [9.921 MB]

TUPPC094

Experimental Observations of Large-amplitude Solitary Waves in Electron Beams

space-charge, electron, laser, longitudinal-dynamics

1377

Y. Mo, B.L. Beaudoin, D.W. Feldman, I. Haber, R.A. Kishek, P.G. O'Shea
UMD, College Park, Maryland, USA
J.C.T. Thangaraj
Fermilab, Batavia, USA

Funding: Work funded by the US Dept. of Energy Offices of Fusion Energy Sciences and High Energy Physics and Fusion Energy Sciences, and by the Dept. of Defense Office of Naval Research.
The longitudinal dynamics of space charge dominated beams plays an important role in particle accelerators and other applications such as heavy ion fusion and free electron lasers (FELs). All beams are space-charge dominated near the source. Furthermore, the longitudinal profile is not necessarily an ideal mathematical function. By means of experiments on the University of Maryland Electron Ring (UMER), we studied how a perturbation to the line charge density could affect the beam propagation. By varying the initial amplitude of the perturbation, we access nonlinear space charge physics. When starting with large-amplitude perturbations, we have observed, for the first time in charged particle beams, solitary waves for which the nonlinear steepening exactly balances the wave dispersion, leading to persistent waves that preserves their shape over a long distance. This paper presents the results of the soliton experiments, including systematic studies of the dependence of the soliton propagation on beam current, perturbation level and width. The data is compared with theory and simulation.

TUPPD019

New Injector for the EMMA ns-FFAG Ring

booster, cavity, linac, emittance

1449

B.D. Muratori
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

EMMA is the world’s first non-scaling FFAG which has recently demonstrated acceleration in the serpentine channel. At present, the electron beam is injected into EMMA from the ALICE accelerator. However, funding will be re-directed to an Electron Beam Test Facility (EBTF) in the near future, therefore, in order to continue the broad portfolio of planned experiments required to characterize non-scaling FFAGs, it essential to consider an alternative injection scheme. In this paper, we propose re-utilizing a thermionic gun and a 12 MeV linac from the SRS (Synchrotron Radiation Source) at Daresbury Laboratory. The paper looks at how the required EMMA beam properties can be matched with this new set-up and the advantages and disadvantages involved.

TUPPD034

Multi-bunch Beam Generation by Photo-cathode RF Gun for KEK-STF

cavity, laser, cathode, electron

1479

M. Kuriki, S. Hosoda, H. Iijima
HU/AdSM, Higashi-Hiroshima, Japan
A. Ayaka
Sokendai, Ibaraki, Japan
H. Hayano, J. Urakawa, K. Watanabe
KEK, Ibaraki, Japan
G. Isoyama, R. Kato, K. Kawase
ISIR, Osaka, Japan
S. Kashiwagi
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
K. Sakaue
RISE, Tokyo, Japan

Funding: MEXT, Quantum beam project.
KEK-STF is doing R&D of Super-Conducting (SC) accelerator technology for ILC (International Linear Collider), based on 1.3 GHz RF system. For STF and ILC, the pulse length is 1ms and the repetition is 5Hz. We developed a L-band Normal-Conducting RF gun designed by DESY to provide electron beam over such long pulse duration. For NC Photo-cathode RF gun, such high duty and long pulse operation is a challenging task, because the detuning by the heat load of cavity dissipation power is significant. The RF gun provides the electron pulse train to SC accelerator modules which will be operated at 31.5 MV/m gradient. Precise RF control is essential for SC accelerator because the beam loading and input RF power should be well ballanced for a stable operation. The beam test to demonstrate the stable opeation is very important for SC accelerator R&D. The system is also used to demonstrate high-flux quasi-monochromatic X-ray generation by inverse Compton scattering at KEK-STF. The experiment is carried out from April 2012 to November 2012 at KEK-STF. We report the latest status of the multi-bunch generation by the RF gun.

TUPPD035

SuperKEKB Injector Upgrade for High Charge and Low Emittance Electron Beam

emittance, alignment, wakefield, cathode

1482

M. Yoshida, N. Iida, Y. Ogawa, M. Sato, L. Zang
KEK, Ibaraki, Japan

The design strategy of SuperKEKB is based on the nano-beam scheme. The dynamic aperture decreases due to the very small beta function at the interaction point. Thus the injector upgrade is required to obtain the low emittance and high charge beam corresponding to the short beam life and small injection acceptance. The required beam parameters are 5 nC, 20 mm mrad and 4 nC, 6 mm mrad for the electron and positron respectively. For the electron beam, new photocathode RF-Gun with the focusing electric field was installed. Further the emittance growth in the linac is an important issue for the low emittance injection. We will report the machine study of the RF-Gun and the emittance growth through the linac.

TUPPD054

Research Activities on Photocathodes for HZDR SRF Gun

cathode, SRF, vacuum, electron

1524

R. Xiang
FZD, Dresden, Germany
A. Arnold, M. Freitag, P. Michel, P. Murcek, J. Teichert
HZDR, Dresden, Germany

Funding: We acknowledge the support of the European Community-Research Infrastructure Activity (EuCARD, contract number 227579), as well German Federal Ministry of Education and Research grant 05 ES4BR1/8.
Since 2005 the photocathode laboratory has been in operation at HZDR. The main goal is to prepare Cs2Te photocathodes for the SRF gun. A vacuum transport system with UHV is used to move the cathodes from preparation lab to accelerator hall. Up to now 31 Cs2Te photocathodes have been deposited and eight of them have been used in the SRF gun. Quantum efficiency of 1% and lifetime of months can be maintained during the gun operation. At the same time activities are directed towards new photocathode materials with high Q.E. for high current electron sources. Cs3Sb and GaN(Cs) photocathodes have been tested as new candidates, and the design of a preparation system for GaAs(Cs, O) is ongoing.

TUPPD057

High Charge Low Emittance RF Gun for SuperKEKB

cathode, emittance, injection, laser

1533

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

We are developing a new RF gun for SuperKEKB. We are upgrading KEKB to SuperKEKB now. 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. Now, we are testing a Disk and Washer (DAW) type RF gun. Its photo cathode material is LaB6. Normally, LaB6 is used as a thermionic cathode, but it is suitable for　long-life photo cathode operation. This gun has a strong focusing field at the cathode and the acceleration field distribution also has a focusing effect. We will obtain 3.2 MeV beam energy with the gun. The design of RF gun and experimental results will be shown.

TUPPD058

Development of an RF Electron Gun for Ultra-Short Bunch Generation

electron, cavity, cathode, simulation

1536

Y. Koshiba, T. Aoki, K. Sakaue, M. Washio
RISE, Tokyo, Japan
T. Takatomi, J. Urakawa
KEK, Ibaraki, Japan

At Waseda University, various researches are done using a photocathode rf electron gun with a 1.6 cell cavity. Now we are developing a new rf cavity specialized for producing an ultra-short electron bunch, with the collaboration of High Energy Accelerator Research Organization (KEK). We have used SUPERFISH for designing the new rf cavity and PARMELA for beam tracking. The new rf cavity has an extra cell following the 1.6 cell. The extra cell can chirp the energy of electron bunch so we call it ECC (Energy Chirping Cell). ECC chirp the energy because we shortened the length of iris just before the ECC and also the length of ECC itself. Moreover, electric field in ECC is made to be stronger than others. We have confirmed on PARMELA that ECC rf gun can generate an 100pC electron bunch less than 200fsec with the energy of 4.5MeV at about 2.5m away from the cathode. Such an ultra-short electron bunch enables us to generate a coherent terahertz light using ultra-short electron bunch by synchrotron radiation or transition radiation. In this conference, we would like to introduce the detail of the design of this new ECC rf gun, the present progresses and future prospects.

TUPPD061

High-Power RF Test of an RF-Gun for PAL-XFEL

laser, emittance, electron, injection

1539

J.H. Hong, J.H. Han, H.-S. Kang, C. Kim, S.H. Kim, C.-K. Min, S.S. Park, S.J. Park, Y.J. Park
PAL, Pohang, Kyungbuk, Republic of Korea
M.S. Chae, I.S. Ko, Y.W. Parc
POSTECH, Pohang, Kyungbuk, Republic of Korea

A photocathode RF-gun for the X-ray free electron laser (XFEL) at the Pohang Accelerator Laboratory (PAL) has been fabricated and tested at PAL. This RF-gun is based on a 1.6-cell cavity with dual-feed waveguide ports and two pumping ports. The RF gun was designed by PAL and POSTECH. The RF-gun has been successfully tested with a cathode electric field gradient up to 126MV/m at a repetition rate of 30 Hz. This paper reports the recent results on the beam test of the RF-gun with high power RF at the gun test facility. We present and discuss the measurements of the basic beam parameters such as charge, energy, energy spread, and transverse emittance.

TUPPD063

Interpretation of Dark Current Experimental Results in HZB SC RF Gun

cavity, simulation, accelerating-gradient, HOM

1545

V. Volkov
BINP SB RAS, Novosibirsk, Russia
R. Barday, T. Kamps, J. Knobloch, A.N. Matveenko, A. Neumann
HZB, Berlin, Germany

Funding: Work supported by Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association VH-NG-636 and HRJRG-214.
The experimental dark current measurement results are obtained on HZB SC RF gun. The field emitters are considered to be random defects on the back wall of the cavity. Conducting wires with 1 micron length, blobs of 200 micron diameter and ”tip on tip” combination of them are taken as dark current emitters in the cavity. RF fields were calculated with CLANS program. The dynamic simulation of dark currents from these emitters fit experimental data. The emitter heating power by RF induced current is four orders of magnitude larger than by the field emitted dark current. The RF induced emitter temperature is proportional to ω1/2 which explains the accelerating gradient limit of a cavity like Kilpatrik law. The RF processing by high order modes seems to be promising.

TUPPD064

Cathode Insert Design for SC RF Guns

cathode, cavity, multipactoring, HOM

1548

V. Volkov
BINP SB RAS, Novosibirsk, Russia
R. Barday, T. Kamps, J. Knobloch, A.N. Matveenko
HZB, Berlin, Germany

Funding: Work supported by Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Assiciation VH-NG-636 and HRJRG-214.
The cathode inserts in superconducting (SC) RF guns are normal conducting devices attached to a SC RF gun cavity. They enable the photocathode replacement and, at the same time, preserve high quality factor and high fields in the RF guns. However, the insert may also limit the gun performance because of multipacting etc. The experience gathered in early designs at Wuppertal [1], and, more recently at BNL [2] and HZDR [3] is taken into account. We consider the design structure of the cathode insert worked out by BINP for 1 cell prototype of SC HZDR RF gun [4]. The detailed electric, mechanic, and thermal calculations of the initial [4] and the upgraded design are presented in this paper.
* A. Michalke et al., EPAC'92, p. 1014 (1992).
** A. Burrill et al., PAC07, p. 2544 (2007).
*** D. Janssen et al., NIM A507, 314 (2003).
**** D. Janssen et al., NIM A445, 408 (2000).

TUPPD065

An Electron Gun Test Stand to Prepare for the MAX IV Project

cathode, injection, coupling, linac

1551

S. Werin, E. Elafifi, M. Eriksson, D. Kumbaro, F. Lindau, S. Thorin
MAX-lab, Lund, Sweden
E. Mansten
Lund University, Division of Atomic Physics, Lund, Sweden

The MAX IV facility, currently under construction, will include a 3 GeV linac injector with two RF guns providing beams for the two operations modes: ring injection and the Short Pulse Facility. The ring injection will be done by a thermionic 3 GHz RF gun developing from the current MAX-lab RF gun. The SPF gun will be a laser driven photo cathode 3 GHz RF gun based on the 1.6 cell BNL/SLAC type. The guns will be operated with short (0.7 us) RF pulses from a SLED system. A test stand to fine tune the operation of the two different systems has been assembled at the MAX IV laboratory (former MAX-lab). The experience in RF commissioning and initial measurements of energy, charge and quantum efficiency will be reported and the extension of the test stand for full emittance characterization will be outlined.

TUPPD066

Lifetime Studies of Cs2Te Cathodes at the PHIN RF Photoinjector at CERN

vacuum, cathode, laser, beam-losses

1554

C. Heßler, E. Chevallay, M. Divall Csatari, S. Döbert, V. Fedosseev
CERN, Geneva, Switzerland

The PHIN photoinjector has been developed to study the feasibility of a photoinjector option for the CLIC (Compact LInear Collider) drive beam as an alternative to the baseline design, using a thermionic gun. The CLIC drive beam requires a high charge of 8.4 nC per bunch in 0.14 ms long trains, with 500 MHz bunch spacing and 50 Hz macro pulse repetition rate, which corresponds to a total charge per macro pulse of 0.59 mC. This means unusually high peak and average currents for photoinjectors and is challenging with respect to the cathode lifetime. In this paper detailed studies of the lifetime of Cs2Te cathodes, produced by the co-evaporation technique, with respect to bunch charge, train length and vacuum level are presented. Furthermore, the impact of the train length and bunch charge on the vacuum level will be discussed and steps to extend the lifetime will be outlined.

TUPPD068

Design of the Production and Measurement of Ultra-Short Electron Bunches from an S-band RF Photoinjector

cavity, dipole, electron, laser

1560

J.W. McKenzie, D. Angal-Kalinin, J.K. Jones, B.L. Militsyn
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The Electron Beam Test Facility (EBTF) is planned for installation in late 2012 at Daresbury Laboratory. An S-band RF photoinjector provides ultrashort, low emittance electron bunches up to 6 MeV. A suite of diagnostics has been designed to fully characterise the bunches. A particular focus has been on producing and measuring bunch lengths less than 100 fs. This can be achieved with a multi-cell standing wave S-band transverse deflecting cavity. Operating such a cavity with low energy electrons provides certain challenges which are discussed in this paper with respect to beam dynamic simulations.

TUPPD069

Schottky-Enabled Photoemission and Dark Current Measurements - Toward an Alternate Approach to Fowler-Nordheim Plot Analysis

laser, site, photon, cathode

1563

E.E. Wisniewski, W. Gai, J.G. Power
ANL, Argonne, USA
H. Chen, Y.-C. Du, Hua, J.F. Hua, W.-H. Huang, C.-X. Tang, L.X. Yan, Y. You
TUB, Beijing, People's Republic of China
A. Grudiev, W. Wuensch
CERN, Geneva, Switzerland
E.E. Wisniewski
Illinois Institute of Technology, Chicago, Illinois, USA

Field-emitted dark current, a major gradient-limiting factor in RF cavities, is usually analyzed via Fowler-Nordheim (FN) plots. Traditionally, field emission is attributed to geometrical perturbations on the bulk surface whose field enhancement factor (beta) and the emitting area (A) can be extracted from the FN plot. Field enhancement factors extracted in this way are typically much too high (1 to 2 orders of magnitude) to be explainable by either the geometric projection model applied to the measured surface roughness or by field enhancement factors extracted from Schottky-enabled photoemission measurements. We compare traditional analysis of FN plots to an alternate approach employing local work function variation. This is illustrated by comparative analysis of recent dark current and Schottky-enabled photoemission data taken at Tsinghua S-band RF gun. We conclude by describing a possible experimental plan for discrimination of variation of local work function vs. local field enhancement.

TUPPD076

Photocathode Studies for the SPEAR3 Injector RF Gun

cathode, linac, laser, klystron

1575

S. Park, W.J. Corbett, S.M. Gierman, J.R. Maldonado
SLAC, Menlo Park, California, USA

Funding: Work supported by U.S. Department of Energy Contract DE-AC03- 76SF00515 and Office of Basic Energy Sciences, Division of Chemical Sciences.
The electron gun for the SPEAR3 injector operates with a warm thermionic dispenser cathode immersed in a 1.5-cell RF structure. At each injection cycle the gun accelerates several thousand electron bunches up to ~3 MeV during a 2.5us rf pulse. The individual bunches are then compressed by an alpha magnet and a traveling-wave chopper selects 3-5 bunches so they don’t cause beam loading to the linac, where the accelerated bunches reach 120 MeV for subsequent capture in a single booster synchrotron bucket. Tests are underway to operate the dispenser cathode as a cold electron photo-emitter driven by an external laser system. Eventually, without the copper, this will enable multi-bunch injections to the Booster and SPEAR3. In parallel, tests are underway to evaluate quantum efficiency and beam emittance for a beam emitted from a CsBr photocathode with ns- and ps-pulses of UV laser light. In this paper we report on both the cold cathode electron gun operation studies for SPEAR3 and the CsBr research aimed at developing advanced cathode materials for future applications.

TUPPD078

A Novel Design of a High Brightness Superconducting RF Photoinjector Gun Cavity

cavity, SRF, cathode, emittance

1581

F. Marhauser, R. Rodriguez
MuPlus, Inc., Newport News, USA
Z. Li
SLAC, Menlo Park, California, USA

Funding: Work supported under U.S. DOE Grant Application Number 98802B12-I
Next generation electron accelerators for research, medical, defense or industrial use are in need of electron sources operating at high repetition rates of 1 MHz and beyond, with normalized emittance of 1 mm-mrad or less and bunch charges as much as one nC or more. A conceptual layout of a novel superconducting RF photoinjector gun cavity (SRF gun) is proposed, which can provide unprecedented flexibility to vary beam pulse patterns in the MHz regime and beyond at average currents around 1 mA. It does not require an opening in the center of the back wall and avoids the complex cathode exchange system, but still allows an exchange or refurbishment of the cathode. The demountable back plate has the major benefit to clean the cavity cells independently from the back wall carrying a superconductive photocathode. This mitigates risks of cavity contamination and eases fabrication and chemical post-processing to achieve high accelerating fields, a key parameter to guarantee high brightness beams.

TUPPD079

Design of an L-Band RF Photoinjector for the Idaho Accelerator Center 44 MeV Linac

linac, emittance, laser, solenoid

1584

M. Titberidze, A.W. Hunt, D.P. Wells
IAC, Pocatello, IDAHO, USA
Y. Kim
ISU, Pocatello, Idaho, USA

At the Idaho Accelerator Center (IAC) of Idaho State University, we have been operating a 44 MeV L-band RF (1300 MHz) linear accelerator (LINAC) for various user applications such as medical isotope production, Laser Compton Scattering (LCS), positron annihilation energy spectroscopy, and photo fission. But the LINAC is not optimized properly to supply high quality electron beam for those experiments due to limitations of an existing 85 kV thermionic DC gun. In the near future, we are planning to use the L-band LINAC for new user applications such as Accelerator Driven subcritical nuclear reactor System (ADS), photon tagging facility, Ultrafast Electron Diffraction (UED) facility, and high power coherent Terahertz light source facility. Therefore, recently, we have been studying a future upgrade of the L-band LINAC with an RF photoinjector using ASTRA code. In this paper, we describe ASTRA simulation results and a new layout of the L-band LINAC, which is based on an L-band 1.5 cell RF photoinjector. Then, we describe its expected performance for two different single bunch charges (1 nC and 5 nC).

TUPPD080

Design of Ultrafast High-Brightness Electron Source

cathode, electron, brightness, laser

1587

J.H. Park, H. Bluem, J. Rathke, T. Schultheiss, A.M.M. Todd
AES, Princeton, New Jersey, USA

Funding: This work was supported by the U.S. Department of Energy, under Contract No. DE-SC0006210.
Generation and preservation of ultrafast electron beams is one of the major challenges in accelerator R&D. Space charge forces play a fundamental role in emittance dilution and bunch lengthening for all high brightness beams. In order to generate and preserve the ultrafast high-brightness electron beam, transverse and longitudinal space charge effects have to be considered. Several approaches to achieving ultra-short bunches have been explored such as velocity bunching and magnetic compression. However, each option suffers drawbacks in achieving a compact ultrafast high-brightness source. We present an alternative scheme to achieve an ultrafast high-brightness electron beam using a radial bunch compression technique in an x-band photocathode RF electron gun. By compensating the path length difference with a curved cathode and using an extremely high acceleration gradient (greater than 200 MV/m), we seek to deliver 100 pC, 100 fsec bunches.

TUPPD081

Development of Carbon NanoTube (CNT) Cathodes at RadiaBeam

cathode, vacuum, high-voltage, electron

1590

L. Faillace, R.B. Agustsson, S. Boucher, A.Y. Murokh, A.V. Smirnov
RadiaBeam, Santa Monica, USA

RadiaBeam is developing Carbon Nanotube (CNT) cathodes for DC-pulsed and radio frequency (RF) driven electron sources. CNT cathodes, if realized, are capable of producing very high current density with low thermal emittance, due to ambient operating temperature. The initial experimental results of CNT cathodes are presented, including the high-voltage tests, and life time studies. CNT cathodes potential applications in accelerator science and microwave industry are discussed, and near term plans to test the CNT cathodes in the RF environment are presented.

TUPPD082

Simulations of Multipacting in the Cathode Stalk and FPC of 112 MHz Superconducting Electron Gun

electron, cathode, simulation, niobium

1593

T. Xin, X. Liang
Stony Brook University, Stony Brook, USA
S.A. Belomestnykh, I. Ben-Zvi, T. Rao, J. Skaritka, E. Wang, Q. Wu
BNL, Upton, Long Island, New York, USA
X. Chang
Far-Tech, Inc., San Diego, California, USA

Funding: Work is supported at BNL by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. The work at Stony Brook is supported by the US DOE under grant DE-SC0005713.
A 112 MHz superconducting quarter-wave resonator electron gun will be used as the injector of the Coherent Electron Cooling (CEC) proof-of-principle experiment at BNL. Furthermore, this electron gun can be used for testing of the performance of various high quantum efficiency photocathodes. In a previous paper, we presented the design of the cathode stalks and a Fundamental Power Coupler (FPC). In this paper we present updated designs of the cathode stalk and FPC. Multipacting in the cathode stalk and FPC was simulated using three different codes, Multipac, CST particle studio and FishPact respectively. All simulation results show no serious multipacting in the cathode stalk structure and FPC.

TUPPP012

Optimization of the Beam Optical Parameters of the Linac-based Terahertz Source FLUTE

laser, space-charge, linac, simulation

1629

S. Naknaimueang, E. Huttel, A.-S. Müller, M.J. Nasse, R. Rossmanith, M. Schuh, M. Schwarz, P. Wesolowski
KIT, Karlsruhe, Germany
M.T. Schmelling
MPI-K, Heidelberg, Germany

Funding: Karlsruher Institut für Technologie.
FLUTE is a compact accelerator (consisting of a 7 MeV laser gun, a 50 MeV linac, and bunch compressors) under construction at KIT in Karlsruhe for producing coherent THz radiation. The programs ASTRA and CSRtrack were used to optimize the beam parameters. The aim was to minimize the bunch length used in various THz experiments, with bunch charges between 100 pC and 3 nC. It was calculated that the bunch length after compression depends both on the bunch current and the transverse beam size. The transverse beam size depends on the laser spot size at the cathode of the 7 MeV laser gun. Further simulations showed that a larger beam size reduces the efficiency of the compressor. This problem is cured by focusing elements with a focusing strength depending on the space charge after the gun and integrated into the various compressors layouts under study (four magnets, two magnets and quadrupoles, etc.). The results of these calculations are presented in this paper.

TUPPP038

Electron Beam Collimation for the Next Generation Light Source

collimation, undulator, linac, impedance

1695

C. Steier, P. Emma, H. Nishimura, C. F. Papadopoulos, F. Sannibale
LBNL, Berkeley, California, USA

Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The Next Generation Light Source will deliver high (MHz) repetition rate electron beams to an array of free electron lasers. Because of the significant average current in such a facility, effective beam collimation is extremely important to minimize radiation damage to undulators, prevent quenches of superconducting cavities, limit dose rates outside of the accelerator tunnel and prevent equipment damage. This paper describes the conceptual design of the collimator system, as well as the results of simulations to test its effectiveness.

TUPPP060

Injector Design for PAL-XFEL Project

laser, emittance, solenoid, cathode

1732

J.H. Han, M.S. Chae, J.H. Hong, I. Hwang, H.-S. Kang, I.S. Ko, S.J. Park
PAL, Pohang, Kyungbuk, Republic of Korea

Funding: The Ministry of Education, Science and Technology of the Korean Government
The PAL-XFEL project has the baseline specification of FEL radiation down to 0.1 nm with a 10 GeV S-band normal conducting linac. To fulfill the requirement of the beam parameter, the S-band photoinjector was designed. Numerical optimizations for nominal and low charge operations are presented.

TUPPP061

Status of the PAL-XFEL Project

undulator, linac, electron, FEL

1735

J.H. Han, H.-S. Kang, I.S. Ko
PAL, Pohang, Kyungbuk, Republic of Korea

Funding: The Ministry of Education, Science and Technology of the Korean Government
PAL-XFEL is designed to generate X-ray radiation in the range of 0.1 and 10 nm for users. The machine consists of a 10 GeV linear accelerator and five undulator beamlines. Electron beams are generated at a low emittance S-band photocathode RF gun and accelerated with an S-band normal conducting linac. Three hard X-ray beamlines will be located at the end of the linac. Electron beams for two soft X-ray beamlines will be switched at a medium energy. The project started in 2011 and the building construction is ongoing. Resent progress of the project and an update of the current progress are presented.

TUPPP070

Next Generation Light Source R&D and Design Studies at LBNL

FEL, linac, electron, laser

1762

J.N. Corlett, B. Austin, K.M. Baptiste, D.L. Bowring, J.M. Byrd, S. De Santis, P. Denes, R.J. Donahue, L.R. Doolittle, P. Emma, D. Filippetto, G. Huang, T. Koettig, S. Kwiatkowski, D. Li, T.P. Lou, H. Nishimura, H.A. Padmore, C. F. Papadopoulos, G.C. Pappas, G. Penn, M. Placidi, S. Prestemon, D. Prosnitz, J. Qiang, A. Ratti, M.W. Reinsch, D. Robin, F. Sannibale, D. Schlueter, R.W. Schoenlein, J.W. Staples, C. Steier, C. Sun, T. Vecchione, M. Venturini, W. Wan, R.P. Wells, R.B. Wilcox, J.S. Wurtele
LBNL, Berkeley, California, USA

Funding: Work supported by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
LBNL is developing design concepts for a multi-beamline soft x-ray FEL array powered by a superconducting linear accelerator, operating with a high bunch repetition rate of approximately one MHz. The cw superconducting linear accelerator is supplied by an injector based on a high-brightness, high-repetition-rate photocathode electron gun. Electron bunches are distributed from the linac to the array of independently configurable FEL beamlines with nominal bunch rates up to 100 kHz in each FEL, and with even pulse spacing. Individual FELs may be configured for different modes of operation, and each may produce high peak and average brightness x-rays with a flexible pulse format, and with pulse durations ranging from sub-femtoseconds to hundreds of femtoseconds. In this paper we describe conceptual design studies and optimizations. We describe recent developments in the design and performance parameters, and progress in R&D activities.

TUPPR055

Upgrading the CEBAF Injector with a New Booster, Higher Voltage Gun, and Higher Final Energy

booster, cryomodule, coupling, cavity

1945

R. Kazimi, A. Freyberger, F.E. Hannon, A.S. Hofler, A. Hutton
JLAB, Newport News, Virginia, USA

Funding: Authored by JSA, LLC under U.S. DOE Contract DE-AC05- 06OR23177. The U.S. Govt. retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this for U.S. Govt. purposes.
The CEBAF accelerator at Jefferson Lab will be upgraded from 6 GeV to 12 GeV in the next few years. To meet the requirement of the new machine and also to take the opportunity to improve the beam quality, the CEBAF injector will be upgraded with a higher voltage gun, a new booster, and a new accelerating RF module. The CEBAF injector creates and accelerates three beams at different currents simultaneously. The beams are interleaved, each at one third of RF frequency, traveling through the same beam line. The higher voltage gun will lower the space charge effects making it easier to operate at different current with the same setup. The new booster with optimized beam dynamics will complete the bunching process and provides initial acceleration matched to the new gun voltage. Using our latest SRF design, the new booster has significantly lower XY coupling effects that should improve our beam setup and operation for the highly sensitive parity experiments scheduled for the CEBAF’s future. Finally, the new accelerating RF module will roughly double the injector final energy to match the rest of the 12 GeV accelerator. In this paper we will provide more detail about this upgrade.

WEXA02

Development of Electron Coolers in Novosibirsk

electron, ion, acceleration, proton

2068

V.V. Parkhomchuk
BINP SB RAS, Novosibirsk, Russia
S. Nagaitsev
Fermilab, Batavia, USA

An electron cooling method was proposed by G. Budker aproximately 50 years ago. Since the first demonstrations of strong cooling in 1972, the Novosibirsk Institute of Nuclear Physics has continued to develop this technique for various machines with increasingly higher energy beams. Recent application of the e-cooling method at LEIR appeared as a crucial application for a high luminosity achieved in lead-lead ion beam collisions at LHC. This talk should describe the fundamental mechanism of strong cooling, describe historical progress at the BINP and present recent results achieved at the LHC. New 2MeV cooler for COSY ring under commissioning just now at BINP.

Slides WEXA02 [7.872 MB]

WEOAA03

Development of the Beam Halo Monitor in the J-PARC 3-GeV RCS

extraction, injection, electron, beam-losses

2122

M. Yoshimoto, N. Hayashi, H. Hotchi, M. Kinsho, S.I. Meigo, K. Okabe, P.K. Saha, K. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

Transverse beam halo is one of the most important beam parameters due to limit the performance of the high intensity beam accelerator. Therefore the transverse beam halo measurement is required to increase the beam power of the J-PARC 3-GeV RCS. Transverse halo monitors, which are horizontal and vertical scanning aluminum plates type, has been installed in the extraction beam line. But the residual secondary electrons hindered the beam halo diagnostic. Thus we develop the new beam halo monitor with vibrating wire monitor.

Slides WEOAA03 [6.701 MB]

WEOBA01

Construction Progress of the RHIC Electron Lenses

electron, solenoid, proton, dipole

2125

W. Fischer, Z. Altinbas, M. Anerella, E.N. Beebe, M. Blaskiewicz, D. Bruno, W.C. Dawson, D.M. Gassner, X. Gu, R.C. Gupta, K. Hamdi, J. Hock, L.T. Hoff, A.K. Jain, R.F. Lambiase, Y. Luo, M. Mapes, A. Marone, T.A. Miller, M.G. Minty, C. Montag, M. Okamura, A.I. Pikin, S.R. Plate, D. Raparia, Y. Tan, C. Theisen, P. Thieberger, J.E. Tuozzolo, P. Wanderer, S.M. White, W. Zhang
BNL, Upton, Long Island, New York, USA

Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH10886 with the U.S. Department of Energy.
In polarized proton operation, the RHIC performance is limited by the head-on beam-beam effect. To overcome these limitations two electron lenses are under construction. We give an overview of the progress over the last year. Guns, collectors and the warm electron beam transport solenoids with their associated power supplies have been constructed. The superconducting solenoids that guide the electron beam during the interaction with the proton beam are near completion. A test stand has been set up to verify the performance of gun, collector and some of the instrumentation. The RHIC infrastructure is being prepared for installation, and simulations continue to optimize the performance.

Slides WEOBA01 [7.672 MB]

WEOAB02

Photocathode R&D at Cornell University

electron, vacuum, emittance, cathode

2137

L. Cultrera, I.V. Bazarov, J.V. Conway, B.M. Dunham, Y. Hwang, Y. Li, X. Liu, R. Merluzzi, T.P. Moore, K.W. Smolenski
CLASSE, Ithaca, New York, USA
S.S. Karkare, J.M. Maxson, W.J. Schaff
Cornell University, Ithaca, New York, USA

Funding: This work has been supported by NSF DMR-0807731 and by DOE DE-SC0003965.
A wide R&D program is pursued at Cornell University aimed at preparation and characterization of high efficiency photocathodes for the Energy Recovery Linac photoinjector. The currently investigated photoemitters include both positive and negative electron affinity materials such as respectively bi-alkali antimonide and III-V semiconductors activated with Cs and either O or F. Analysis techniques as Scanning Auger Spectroscopy, Low Energy Electron Diffraction, Reflected High Energy Electron Diffraction and work function measurements are used to characterize the surfaces properties of the specimens. Spectral response, photoemission uniformity, electron energy distributions are used to characterize the quality of the photoelectron beam and to relate it to the measured surface properties.

Slides WEOAB02 [6.934 MB]

WEEPPB004

Status of the APEX Project at LBNL

cathode, cavity, laser, electron

2173

F. Sannibale, B.J. Bailey, K.M. Baptiste, J.M. Byrd, C.W. Cork, J.N. Corlett, S. De Santis, L.R. Doolittle, J.A. Doyle, P. Emma, J. Feng, D. Filippetto, G. Huang, H. Huang, T.D. Kramasz, S. Kwiatkowski, W.E. Norum, H.A. Padmore, C. F. Papadopoulos, G.C. Pappas, G.J. Portmann, J. Qiang, D.G. Quintas, J.W. Staples, T. Vecchione, M. Venturini, M. Vinco, W. Wan, R.P. Wells, M.S. Zolotorev, F.A. Zucca
LBNL, Berkeley, California, USA
M. J. Messerly, M.A. Prantil
LLNL, Livermore, California, USA
C.M. Pogue
NPS, Monterey, California, USA

Funding: This work was 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 is focused on the development of a high-brightness high-repetition rate (MHz-class) electron injector for X-ray FEL applications. The injector is based on a new concept gun, utilizing a normal conducting 186 MHz RF cavity operating in cw mode in conjunction with high quantum efficiency photocathodes capable of delivering the required repetition rates with available laser technology. The APEX activities are staged in 3 main phases. In Phases 0 and I, the gun will be tested at its nominal energy of 750 keV and several different photocathodes are tested at full repetition rate. In Phase II, a pulsed linac will be added for accelerating the beam at several tens of MeV to reduce space charge effects and measure the high-brightness performance of the gun when integrated in an injector scheme. At Phase II energies, the radiation shielding configuration of APEX limits the repetition rate to a maximum of several Hz. Phase 0 is under commissioning, Phase I under installation, and initial activities for Phase II are underway. This paper presents an update on the status of these activities.

WEEPPB007

Initial Testing of the Mark-0 X-band RF Gun at SLAC

solenoid, vacuum, radiation, cathode

2179

A.E. Vlieks, C. Adolphsen, V.A. Dolgashev, J.R. Lewandowski, C. Limborg-Deprey, S.P. Weathersby
SLAC, Menlo Park, California, USA

A new X band RF Gun (Mark-0) has been assembled, tuned and is being tested in the ASTA facility at SLAC. This gun has been improved from an earlier gun used in Compton-scattering experiments at SLAC by the introduction of a racetrack dual-input coupler to reduce quadrupole fields. Waveguide-to-coupler irises were also redesigned to reduce surface magnetic fields and therefore peak pulse surface heating. Tests of this photocathode gun will allow us to gain early operational experience for beam tests of a new gun with further improvements (Mark-1) being prepared for SLAC’s X-Band Test Accelerator (XTA) program and the LLNL MegaRay program. Results of current testing up to ≈ 200 MV/m peak surface Electric fields will be presented.

WEPPC111

Multipacting Simulation ADN Test Results of BNL 704 MHz SRF Gun

cavity, cathode, SRF, simulation

2480

W. Xu, S.A. Belomestnykh, I. Ben-Zvi, C. Cullen, H. Hahn, X. Liang, G.T. McIntyre, D. Pate, S.P. Pontieri, C. Schultheiss, T. Seda, T.N. Tallerico, R. Than, R.J. Todd, S.J. Tuozzolo, A. Zaltsman
BNL, Upton, Long Island, New York, USA
J. Dai
SBU, Stony Brook, New York, USA
L.R. Hammons
Stony Brook University, Stony Brook, USA

Funding: This work was supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
The BNL 704 MHz SRF gun has a grooved choke joint to support the photo-cathode. Due to the distortion of grooves at the choke joint during the BCP for the choke joint, several multipacting barriers showed up when it was tested with Nb cathode stalk at JLab. We built a setup to use the spare large grain SRF cavity to test and condition the multipacting at BNL with various power sources. The test is carried out with three steps: cavity, cavity with Nb cathode stalk, and cavity with copper cathode stalk. This paper summarizes the results of multipacting simulation, and presents large grain cavity test setup and the test results.

WEPPC114

Design, Simulation and Conditioning of the Fundamental Power Couplers for BNL SRF Gun

simulation, vacuum, SRF, klystron

2489

W. Xu, Z. Altinbas, S.A. Belomestnykh, I. Ben-Zvi, S. Deonarine, D.M. Gassner, J.P. Jamilkowski, P. Kankiya, D. Kayran, N. Laloudakis, L. Masi, G.T. McIntyre, D. Pate, D. Phillips, T. Seda, A.N. Steszyn, T.N. Tallerico, R.J. Todd, D. Weiss, A. Zaltsman
BNL, Upton, Long Island, New York, USA
M.D. Cole, G.J. Whitbeck
AES, Medford, NY, USA

Funding: This work was supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
The 704 MHz SRF gun for the BNL Energy Recovery Linac (ERL) prototype uses two fundamental power couplers (FPCs) to deliver up to total 1 MW of CW RF power into the half-cell cavity. To prepare the couplers for high-power RF service and process multipacting, the FPCs should be conditioned prior to installation into the gun cryomodule. A room-temperature test stand was configured for conditioning FPCs in full reflection regime with varied phase of the reflecting wave. The FPCs have been conditioned up to 250 kW in pulse mode and 125 kW in CW mode. The multipacting simulations were carried out with Track3P code developed at SLAC. The simulations matched the experimental results very well. This paper presents the FPC RF and thermal design, multipacting simulations and conditioning of the BNL gun FPCs.

WEPPD047

Sequencer Design of Timing System for the Taiwan Photon Source

injection, controls, booster, EPICS

2621

C.Y. Wu, Y.-T. Chang, J. Chen, Y.-S. Cheng, P.C. Chiu, K.T. Hsu, K.H. Hu, C.H. Kuo, C.Y. Liao
NSRRC, Hsinchu, Taiwan

The timing system of the Taiwan Photon Source is used to distribute trigger signals and synchronously clocks to all the equipment of the machine which need them. The timing system basically works by sending event codes from one event generator (EVG) through tree structured, bidirectional optical fiber network to many event receivers. To accommodate various operation and injection scenarios of the TPS storage ring and booster synchrotron and LINAC, timing sequencer design and control is crucial. The sequencer (event code) is stored at sequence RAM of the EVG module. In order to manage sequence RAM of EVG, the timing sequence control is considered to use Matlab scripts embedded in the timing master EPICS IOC. The timing sequencer design will be summarized in this paper.

WEPPD056

Ytterbium Fiber Laser System of DAW RF Gun for SuperKEKB

laser, emittance, cavity, luminosity

2648

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

For obtaining higher luminosity in the SuperKEKB, the photocathode DAW-type RF gun for high-current, low-emittance beams will be employed in the injector linac. The electron beams with a charge of 5 nC and a normalized emittance of 10 micrometer are expected generate in the photocathode RF gun by using the laser source with a center wavelength of 260 nm and a pulse width of 30 ps. Fiber laser especially Ytterbium(Yb) fiber have attracted attention as one of the promising practical alternatives to usual solid-state lasers, offering high energy-extraction efficiency, high repetition rate, high output power, low-cost and so on. Introducing the Ytterbium fiber laser system, we have developed a stable laser amplifier system, which could allow steady beam injection into the SuperKEKB rings. The laser system starts with a large mode-area Yb-doped fiber-based amplifier system, which consists of a passively mode-locked femtosecond Yb-fiber oscillator. To obtain the mJ-class pulse energy, a multi-pass solid-state amplifier is employed. Deep UV pulses for the photocathode are generated by using two frequency-doubling stages. High pulse energy and good stability would be expected.

WEPPD069

PLS-II Linac Upgrade

linac, electron, klystron, emittance

2681

B.-J. Lee, J.Y. Choi, S. Chunjarean, T. Ha, J.Y. Huang, I. Hwang, Y.D. Joo, C. Kim, M. Kim, S.H. Kim, S.J. Kwon, S.H. Nam, S.S. Park, S.J. Park, S. Shin, Y.G. Son
PAL, Pohang, Kyungbuk, Republic of Korea

This paper reports on the recent status of the Pohang Light Source (PLS)-II linac at Pohang Accelerator Laboratory (PAL). From 2009, the linac upgrade has been started increasing its energy from 2.5 GeV to 3 GeV aiming stable top-up mode operation. First, we show that the stability status of the two different types of modulators to meet the top-up condition which requires very stable modulator system in linac. Next, we introduce upgrade status those differ from their PLS (2.5 GeV) such as installation of the dual vacuum systems for the electron gun to replace it immediately, adding important diagnostic tools, and reutilization of the beam analysis system just after pre-injector. Finally we present the electron beam parameters measured by those diagnostic system.

WEPPD082

Characterization of Photocathode Damage during High Current Operation of the Cornell ERL Photoinjector

ion, site, vacuum, linac

2717

J.M. Maxson, S.S. Karkare
Cornell University, Ithaca, New York, USA
I.V. Bazarov, S.A. Belomestnykh, L. Cultrera, D.S. Dale, J. Dobbins, B.M. Dunham, K. Finkelstein, R.P.K. Kaplan, V.O. Kostroun, Y. Li, X. Liu, F. Löhl, B. Pichler, P. Quigley, D.H. Rice, K.W. Smolenski, M. Tigner, V. Veshcherevich, Z. Zhao
CLASSE, Ithaca, New York, USA

The Cornell ERL Photoinjector prototype has recently demonstrated successful operation at 20 mA for 8 hours using a bi-alkali photocathode grown on a Si substrate. The photocathode film was grown off center, and remained relatively undamaged; however, upon removal from the gun, the substrate at the gun electrostatic center displayed significant visible damage. Here we will describe not only the parameters of that particular high current run, but a suite of post-operation surface morphology and crystallographic measurements, including X-ray fluorescence, X-ray diffraction, contact profilometry, scanning electron microscopy, performed about the damage site and photocathode film. The data indicate violent topological changes to the substrate surface, as well as significant induced crystallographic strain. Ion back-bombardment is proposed as a possible mechanism for damage, and a simple model for induced crystal strain is proposed (as opposed to ion induced sputtering), and is shown to have good qualitative agreement with the spatial distribution of damage.

WEPPD084

The E-Lens Test Bench for Rhic Beam-Beam Compensation

electron, controls, dipole, cathode

2720

X. Gu, Z. Altinbas, J.N. Aronson, E.N. Beebe, W. Fischer, D.M. Gassner, K. Hamdi, J. Hock, L.T. Hoff, P. Kankiya, R.F. Lambiase, Y. Luo, M. Mapes, J.-L. Mi, T.A. Miller, C. Montag, S. Nemesure, M. Okamura, R.H. Olsen, A.I. Pikin, D. Raparia, P.J. Rosas, J. Sandberg, Y. Tan, C. Theisen, P. Thieberger, J.E. Tuozzolo, W. Zhang
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
To compensate for the beam-beam effects from the proton-proton interactions at IP6 and IP8 in the Relativistic Heavy Ion Collider (RHIC), we are fabricating two electron lenses that we plan to install at RHIC IR10. Before installing the e-lenses, we are setting-up the e-lens test bench to test the electron gun, collector, GS1 coil, modulator, partial control system, some instrumentation, and the application software. Some e-lens power supplies, the electronics for current measurement will also be qualified on test bench. The test bench also was designed for measuring the properties of the cathode and the profile of the beam. In this paper, we introduce the layout and elements of the e-lens test bench; and we discuss its present status towards the end of this paper.

WEPPP025

A Test-bed for Future Linear Collider Technology: Argonne Wakefield Accelerator Facility (AWA)

wakefield, electron, linac, acceleration

2778

M.E. Conde, D.S. Doran, W. Gai, R. Konecny, W. Liu, J.G. Power, Z.M. Yusof
ANL, Argonne, USA
S.P. Antipov, C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
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.
Research at the AWA Facility has been focused on the development of electron beam driven wakefield structures. Accelerating gradients of up to 100 MV/m have been excited in dielectric loaded cylindrical structures operating in the microwave range of frequencies. Several upgrades, presently underway, will enable the facility to explore higher accelerating gradients, and also be able to generate longer RF pulses of higher intensity. The upgraded 75 MeV drive beam will consist of bunch trains of up to 32 bunches spaced by 0.77 ns with up to 100 nC per bunch. The RF pulses generated by the drive bunches are expected to reach GW power levels, establishing accelerating gradients of hundreds of MV/m.

WEPPP030

Experimental Generation of a Double-bunch Electron Beam by Transverse-to-Longitudinal Phase Space Exchange

laser, electron, focusing, cathode

2789

T.J. Maxwell, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
A.S. Johnson, A.H. Lumpkin, J. Ruan, Y.-E. Sun, R.M. Thurman-Keup
Fermilab, Batavia, USA

Funding: Supported by Fermi Research Alliance, LLC under U.S. Dept. of Energy Contract No. DE-AC02-07CH11359, and Northern Illinois Univ. under US Dept. of Defense DURIP program Contract N00014-08-1-10⁶⁴.
In this paper we demonstrate the generation of a tunable, longitudinal double-pulse electron beam. Experimental results on the generation of electron bunch trains with sub-picosecond structure have been previously reported where an initial transverse electron beam modulation was produced by masking the electron beam directly*. Here the initial transverse structure is imparted by masking of the photoinjector drive laser to effectively produce two horizontally offset beams at photoemission in the RF gun. A longitudinal double-pulse modulation is then realized after a transverse-to-longitudinal phase-space exchange beamline. Longitudinal profile tuning is demonstrated by upstream beam focusing in conjunction with downstream monitoring of single-shot electro-optic spectral decoding of coherent transition radiation.
* Y.-E. Sun et al., Tunable Subpicosecond Electron-Bunch-Train Generation Using a Transverse-To-Longitudinal Phase-Space Exchange Technique, Phys. Rev. Lett. 10⁵, 234801 (2010).

WEPPR031

Injector Beam Dynamics for a High-repetition Rate 4th-generation Light Source

emittance, electron, space-charge, linac

3000

C. F. Papadopoulos, J.N. Corlett, P. Emma, D. Filippetto, G. Penn, J. Qiang, M.W. Reinsch, F. Sannibale, C. Steier, M. Venturini, R.P. Wells
LBNL, Berkeley, California, USA

Funding: This work was supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231.
We report on the beam dynamics studies and optimization methods for a high-repetition (1 MHz) photoinjector based on a VHF normal conducting electron source. The simultaneous goals of beam compression and preservation of 6-dimensional beam brightness have to be achieved in the injector, in order to accommodate a linac driven FEL light source. For this, a parallel, multiobjective optimization algorithm is used. We discuss the relative merits of different injector design points, as well as the constraints imposed on the beam dynamics by technical considerations such as the high repetition rate.

WEPPR041

Design of a Compact Linear Accelerator for the Ultrafast Electron Diffraction Facility

electron, linac, space-charge, emittance

3027

M. Mamtimin, A.W. Hunt, Y. Kim, D.P. Wells
IAC, Pocatello, IDAHO, USA

Ultrafast Electron Diffraction (UED) is a powerful tool to find 3-dimensional structures and dynamical transitions of chemical or biological samples with a femtosecond-range temporal resolution and an angstrom-range spatial resolution. Due to the columbic field of electrons, UED can provide a higher cross section and a higher time resolution than those of the ultrafast photon diffraction with X-ray Free Electron Lasers (XFELs). In this paper, we describe the design concepts and ASTRA simulation results of a compact linac for an UED facility.

WEPPR088

Modeling and Simulation of Retarding Field Analyzers at CESRTA

electron, dipole, simulation, vacuum

3138

J.R. Calvey, J.A. Crittenden, G. Dugan, W. Hartung, J. Makita, M.A. Palmer
CLASSE, Ithaca, New York, USA
M.A. Furman, M. Venturini
LBNL, Berkeley, California, USA

Funding: Work supported by the US National Science Foundation (PHY-0734867 and PHY-1002467), and Department of Energy (DE-FC02-08ER41538).
Over the course of the CESRTA program at Cornell, Retarding Field Analyzers (RFAs) have been installed in drift, dipole, quadrupole, and wiggler field regions of the CESR storage ring. RFAs are used to measure the local electron cloud flux on the vacuum chamber wall. Through the use of a retarding grid and segmented collectors, they also provide information on the energy and transverse distribution of the cloud. Understanding these measurements on a quantitative level requires the use of cloud buildup simulation codes, adapted to include a detailed model of the structure of the RFA and its interaction with the cloud. The nature of this interaction depends strongly on the strength of the local magnetic field. We have developed models for RFAs in drift and dipole regions. The drift model has been cross-checked with bench measurements, and we have compared the RFA-adapted cloud buildup simulations with data. These comparisons have then been used to obtain best fit values for the photo-emission and secondary electron emission characteristics of some of the vacuum chamber materials and cloud mitigating coatings employed at CESRTA.

THYA02

Ultracompact Accelerator Technology for a Next-generation Gamma-Ray Source

klystron, laser, electron, photon

3190

R.A. Marsh, F. Albert, S.G. Anderson, C.P.J. Barty, 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.
This presentation will report on the technology choices and progress manufacturing and testing the injector and accelerator of the 250 MeV ultra-compact Compton Scattering X-ray Source under development at LLNL for homeland security applications.

Slides THYA02 [12.896 MB]

THPPC042

Modified Magnicon for High-Gradient Accelerator R&D

cavity, electron, solenoid, cathode

3377

S.V. Shchelkunov, Y. Jiang, M.A. LaPointe
Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA
J.L. Hirshfield
Omega-P, Inc., New Haven, USA
V.P. Yakovlev
Fermilab, Batavia, USA

Funding: Research supported by the U.S. Department of Energy, Office of High Energy Physics
A self-consistent design is described of a modified 34.3 GHz magnicon amplifier with a TE311-mode output cavity, to replace the existing magnicon at Yale Beam Physics Lab Test Facility whose output cavity operates in the TM310 mode. The main goal for the new design is to achieve robust reliable operation. This is expected since tube performance – according to simulations – is largely insensitive to the magnitude of external dc magnetic fields, including imperfections in magnetic field profile; small changes in gun voltage and current; changes in electron beam radial size; and even poorly matched external circuitry. The new tube, as with its predecessor, is a third harmonic amplifier, with drive and deflection gain cavities near 11.424 GHz and output cavity at 34.272 GHz. The design calculations predict stable output of power of 20-27 MW at a 10 Hz repetition rate in pulses up to 1.3 μs long, with a low probability of breakdown in the output cavity because of low electric fields (less than 650 kV/cm).

THPPC043

Cold Test of an L-band, 2-Cell PWT Photoelectron

cavity, simulation, vacuum, electron

3380

Y. Luo, D. Yu
DULY Research Inc., Rancho Palos Verdes, California, USA
R. Andrews, T.N. Khabiboulline
Fermilab, Batavia, USA

Funding: DOE SBIR Grant No. DE-FG02-06ER84460
An L-band, 1+2/2-cell PWT gun with a coax coupler has been designed for high vacuum polarized electron source applications by DULY Research Inc. A cold test model was fabricated and is currently undergoing test at Fermilab, where the gun will eventually be hot tested. The aluminum cold test model includes an rf/ vacuum sieve, 2 disks, endplates, 6 supporting rods and a 6” CF flange, clamped together during testing. Fermilab made measurements for the cavity resonant frequency and axial field distribution using bead pull. To measure the resonant frequency of the cavity small diameter probes are placed through the vacuum sieve slot. A larger diameter probe can be used as an active tuner. This paper presents the results of the cold test and compares measurements with simulation results from 3D SLAC code Omega3p. The axial field distributions are in good agreement with each other. Frequency deviation is less than 0.5%, well within the experimental accuracy.

THPPC048

Innovative Low-Energy Ultra-Fast Electron Diffraction (UED) System

electron, cathode, vacuum, high-voltage

3395

L. Faillace, S. Boucher
RadiaBeam, Santa Monica, USA
P. Musumeci
UCLA, Los Angeles, California, USA

Funding: Work supported by DOE.
RadiaBeam, in collaboration with UCLA, is developing an innovative, inexpensive, low-energy ultra-fast electron diffraction (UED) system which allows us to reconstruct a single ultrafast event with a single pulse of electrons. Time resolved measurement of atomic motion is one of the frontiers of modern science, and advancements in this area will greatly improve our understanding of the basic processes in materials science, chemistry and biology. The high-frequency (GHz), high voltage, phase-locked RF field in the deflector allows temporal resolution as fine as 100 fs. In this paper, we show the complete design of a UED system based on this concept, including an optimized electron gun, a high-resolution RF deflector, and the post-interaction imaging system.

THPPC071

The Use of a Solid State Analog Television Transmitter as a Superconducting Electron Gun Power Amplifier

cavity, electron, controls, LLRF

3452

J.G. Kulpin, K.J. Kleman
UW-Madison/SRC, Madison, Wisconsin, USA
R.A. Legg
JLAB, Newport News, Virginia, USA

Funding: The electron gun program is supported by DOE award DE-SC0005264, and the University of Wisconsin, Madison.
A solid state analog television transmitter designed for 200 MHz operation is being commissioned as a radio frequency power amplifier on the Wisconsin superconducting electron gun cavity. The amplifier consists of three separate radio frequency power combiner cabinets and one monitor and control cabinet. The transmitter employs rugged field effect transistors built into one kilowatt drawers that are individually hot swappable at maximum continuous power output. The total combined power of the transmitter system is 33 kW at 200 MHz, output through a standard coaxial transmission line. A low level radio frequency system is employed to digitally synthesize the 200 MHz signal and precisely control amplitude and phase.

THPPR044

A New Electron Beam Test Facility (EBTF) at Daresbury Laboratory for Industrial Accelerator System Development

electron, FEL, laser, vacuum

4074

P.A. McIntosh, D. Angal-Kalinin, S.R. Buckley, J.A. Clarke, A.R. Goulden, C. Hill, S.P. Jamison, J.K. Jones, A. Kalinin, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, T.T. Ng, B.J.A. Shepherd, R.J. Smith, S.L. Smith, N. Thompson, A.E. Wheelhouse
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
N. Bliss, G.P. Diakun, A. Gleeson, T.J. Jones, B.G. Martlew, A.J. Moss, L. Nicholson, M.D. Roper, C.J. White
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

Recent UK government funding has facilitated the implementation of a unique accelerator test facility which can provide enabling infrastructures targeted for the development and testing of novel and compact accelerator technologies, specifically through partnership with industry and aimed at addressing applications for medicine, health, security, energy and industrial processing. The infrastructure provision on the Daresbury Science and Innovation Campus (DSIC) will permit research into areas of accelerator technologies which have the potential to revolutionise the cost, compactness and efficiency of such systems. The main element of the infrastructure will be a high performance and flexible electron beam injector facility, feeding customised state-of-the-art testing enclosures and associated support infrastructure. The facility operating parameters and implementation status will be described, along with primary areas of commercialised technology development opportunities.

THPPR049

Study on Electron Microbeam Generation for MRT Based on Photo-cathode RF-Gun

electron, cathode, laser, radiation

4086

Y. Yoshida, K. Sakaue, M. Washio
RISE, Tokyo, Japan

We have been developing an MRT (Microbeam Radiation Therapy) based on Cs-Te photo cathode RF-Gun at Waseda University. MRT is proposed to treat tumor by using array of several micro-meter parallel beams. In this therapy, irradiated normal tissue repairs itself, by contrast, even a non-irradiated tumor tissue dies. In the other words, the microbeam enhances the radiation sensitivity difference between normal and tumor issues. Therefore, MRT is considered one of the most useful tumor therapies in the future. We have generated electron microbeam by tungsten collimator slit and analyzed their dose distribution in air and in the PMMA phantom. We have used radiochromic film called GAFCHROMIC dosimetry film type HD-810 to measure them. We have compared these experimental results with Monte Carlo simulation of the dose distribution using the EGS5 code. In this conference, we would like to report the electron microbeam procedure, optimization of irradiation condition, evaluation of microbeam specifications and future prospects.

THPPR050

Fabrication and High Power RF Test of A C-band 6MeV Standing-wave Linear Accelerating Structure

simulation, coupling, electron, target

4089

J.H. Shao, H. Chen, H. Zha
TUB, Beijing, People's Republic of China

We have designed a C-band standing-wave bi-periodic on-axis coupled linear accelerating structure for industrial and medical applications [1]. The output electron energy is 6MeV and the pulse current intensity is 100mA. The structure has been fabricated and measured in cold test. The cold test results show a good agreement between the simulation and actual measurement. At present, it’s under high power RF test. In this paper, we illustrate the fabrication, the results of cold test and newly high power RF test.

THPPR058

Pulse Radiolysis using Double-decker Femtosecond Electron Beam from a Photocathode RF Gun

electron, linac, laser, radiation

4106

K. Kan, T. Kondoh, K. Norizawa, A. Ogata, J. Yang, Y. Yoshida
ISIR, Osaka, Japan

Pulse radiolysis, which utilizes an electron bunch and a probe light (laser), is a powerful tool that can be used for an observation of ultrafast radiation-induced phenomena. The time resolution in pulse radiolysis depends on the electron bunch length, the probe-light width, and the timing jitter between the electron bunch and the probe light. In order to reduce the jitter, double-decker accelerator, in which separated laser was injected on a photocathode RF gun for a generation of synchronized double electron beams, was applied to pulse radiolysis. One electron beam was used as a pump source of a material, e. g. water, and another as a probe light at 800 nm wavelength with Cherenkov radiation.

THPPR066

Racetrack Microtron for Nondestructive Nuclear Material Detection System

linac, electron, acceleration, microtron

4127

T. Hori, T. Kii, R. Kinjo, H. Ohgaki, M. Omer, H. Zen
Kyoto University, Institute for Advanced Energy, Kyoto, Japan
I. Daito, R. Hajima, T. Hayakawa, M. Kando, H. Kotaki
JAEA, Kyoto, Japan

A nuclear material detection system using the quasi-monochromatic gamma-ray beam from a laser Compton Backscattering source has been proposed for the container inspection, where nuclear resonance fluorescence method would be employed for the specific isotope identification such as U-235. In the system an electron beam of good quality at about 220 MeV for the laser Compton backscattering is required. One candidate for such the practical use is a racetrack microtron which design is based on the existing 150 MeV microtron at JAEA.

FRXBA01

Overview of Recent Progress on High Repetition Rate, High Brightness Electron Guns

cathode, electron, SRF, brightness

4160

F. Sannibale
LBNL, Berkeley, California, USA

In the last few years, the formidable results of x-ray light sources based on FELs opened the door to classes of experiments not accessible before. Operating facilities have relatively low repetition rates (~ 10-100 Hz), and the natural step forward consists in the development of FEL light sources capable of extending their rates by orders of magnitude in the MHz regime. Additionally, ERL based x-ray facilities with their promise of outstanding performance also require extremely high, GHz-class repetition rates. The development of such facilities would represent the next revolutionary step in terms of science capability. To operate such light sources, an electron injector capable of MHz/GHz repetition rates and with the brightness required by X-ray FELs or ERLs is required. Such injector presently does not exist. In response to that, many groups around the world are intensively working on different schemes and technologies that show the potential for achieving the desired results. This presentation includes a description of the requirements for such injectors, an overview of the pursued technologies, and a review of the results obtained so far by the groups active in the field.

Slides FRXBA01 [6.290 MB]

FRXBB01

Femtosecond Electron Guns for Ultrafast Electron Diffraction

electron, emittance, laser, cathode

4170

J. Yang, K. Kan, T. Kondoh, N. Naruse, K. Tanimura, Y. Yoshida
ISIR, Osaka, Japan
J. Urakawa
KEK, Ibaraki, Japan

This talk should describe the development of electron guns for producing femtosecond electron pulses with low (<0.1 micron) emittance, for ultrafast electron diffraction. Comparisons should be made between the systems developed by groups in Asia, Europe and America, outlining any similarities and contrasts. The focus should be on the technology for generating, accelerating, and controlling the bunches, but some description of the science applications should also be included. Finally, prospects for future developments should be considered.

Slides FRXBB01 [7.004 MB]