WG1: Injectors
Paper Title Page
MOIACC002 Development of SRF Gun Applying New Cathode Idea Using a Transparent Superconducting Layer 1
 
  • T. Konomi, Y. Honda, E. Kako, Y. Kobayashi, S. Michizono, T. Miyajima, K. Umemori, S. Yamaguchi, M. Yamamoto
    KEK, Ibaraki, Japan
  • R. Matsuda
    Mitsubishi Heavy Industries Ltd. (MHI), Takasago, Japan
  • T. Yanagisawa
    MHI-MS, Kobe, Japan
 
  KEK has been developing a superconducting RF gun for CW ERL since 2013. The SRF gun is a combination of a 1.3 GHz, 1.5-cell superconducting RF cavity and a backside excitation type photocathode. The photocathode consists of transparent substrate MgAl2O4, transparent superconductor LiTi2O4 and bi-alkali photocathode K2CsSb. The reason for using transparent superconductor is to reflect RF by using the feature of penetration depth of superconductor, which is defined from London equation. It protects optical components from RF damage. The critical DC magnetic field of the cathode, quantum efficiency and initial emittance were measured. These show the cathode can be used for the SRF gun. The gun cavity was designed to satisfy the photocathode operation. Eight vertical tests of the gun cavity have been performed. The surface peak electric field reaches to 75 MV/m with the dummy cathode rod which was made of bulk niobium.  
slides icon Slides MOIACC002 [2.185 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2017-MOIACC002  
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MOIACC003
Progress of VHF Gun and Electron Source Development at SINAP  
 
  • J.Z. Gong, Q. Gu, X.D. Li
    SINAP, Shanghai, People's Republic of China
 
  The R&D work on the VHF gun and high brightness electron source for energy recovery linac (ERL) has been carried out in Shanghai Institute of Applied Physics (SINAP). A 250 MHz RF gun has been designed. The results of cold test and high power test have been presented. In addition, some research and work on high brightness electron sources also have been carried out.  
slides icon Slides MOIACC003 [6.182 MB]  
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MOIBCC001
High Brightness Electron Source Using Cryo-DC Gun  
 
  • I.V. Bazarov
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  Abstract not submitted at print time.  
slides icon Slides MOIBCC001 [21.379 MB]  
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MOIBCC002
Longitudinal Halo From NEA and PEA Photocathodes  
 
  • M.A. Dehn, K. Aulenbacher, V. Bechthold, F. Fichtner
    IKP, Mainz, Germany
  • K. Aulenbacher
    HIM, Mainz, Germany
 
  Funding: BMBF-HOPE II
For high average electron beam currents the length of the electron bunches must match the acceptance of the accelerator. At Johannes Gutenberg-Universität we are able to measure the longitudinal pulse responses of different photocathodes: negative electron affinity (NEA) types and positive electron affinity (PEA) types. With NEA (Cs:GaAs), the pulse response depends on the wavelength of photoexcitation and show at 800nm a long and relatively intense tail whereas at 400nm a similar shape but with orders of magnitude lower intensity is observed. In comparison to this distribution, PEA pulse responses (K2CsSb) show a similar shape as well but another order of magnitude less intensity than NEA in the blue excitation.
 
slides icon Slides MOIBCC002 [2.527 MB]  
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MOIBCC003
Semiconductor Photocathode Development for the BERLinPro SRF Photoinjector  
 
  • J. Kühn
    HZB, Berlin, Germany
 
  At HZB an ERL type accelerator, called BERLinPro, is being built. Cs-K-Sb photocathodes have been identified as electron source for low emittance and high current operation (100 mA). At the moment, the SRF-photoinjector for BERLinPro with an extensive diagnostics beam line is in the commissioning phase, which will also serve as a testbed to assess the performance of in-house produced Cs-K-Sb photocathodes. The deposition of Sb, K and Cs in order to prepare Cs-K-Sb photocathodes is demanding and requests an ultra-high vacuum. Even marginal changes to the process may influence the spectral quantum efficiency, the emittance and the lifetime of the photocathode, and hence change the characteristics of the electron bunch in the SRF-photoinjector. In my talk I will present the latest results of our photocathode research and I will give an update on the status of the SRF-photoinjector and BERLinPro.  
slides icon Slides MOIBCC003 [19.258 MB]  
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MOIBCC004
Multialkali Cathode for High Current Electron Injector: Fabrication, Installation and Testing  
 
  • T. Rao
    BNL, Upton, Long Island, New York, USA
 
  Funding: U.S. Department of Energy under Contract No. DE-AC02-98CH10886
The ability to produce high average current reliably and reproducibly over a long period of time with good quantum efficiency at visible wavelength is important for all ERL applications. There has been considerable interest in developing suitable cathodes for 24/7 operation under such stringent conditions. Recently, at BNL, we have fabricated cathodes with QE in the range of 10% for Cs-K-Sb cathodes and 5% for Na-K-Sb cathodes when irradiated with 532 nm laser and a single pulse charge up to 5 nC in the SRF gun has been produced. In this presentation, we discuss the fabrication of Cs-K-Sb and Na-K-Sb cathodes using both dispensers and effusion cells as sources of alkali metal, characterization of these cathodes, transporting them from the fabrication location to the RHIC tunnel under UHV conditions and installation in the electron guns in the tunnel.
 
slides icon Slides MOIBCC004 [10.458 MB]  
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MOPSPP003
RF Performance and Beam Parameter Measurement of the 2nd 3.5 Cell SRF Gun for ELBE  
 
  • A. Arnold, M. Freitag, P.N. Lu, P. Murcek, H. Vennekate, R. Xiang
    HZDR, Dresden, Germany
  • G. Ciovati, P. Kneisel, L. Turlington
    JLab, Newport News, Virginia, USA
 
  In May 2014 the 1st superconducting photo injector (SRF gun) at HZDR was replaced by a new gun, featuring a new resonator and cryostat. The intention for this upgrade was to reach higher beam energy, higher bunch charge and lower emittance at the same time in order to serve user experiments at the superconducting CW accelerator ELBE. In our contribution we will report on the commissioning of the SRF gun by presenting a full set of RF performance results as well as detailed beam parameter measurements up to a bunch charge of 300 pC. Additionally, we will present the results of the first two user experiments (neutron and THz generation) that demonstrated the reliability of this gun concept.  
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MOPSPP004 Investigation of K2CsSb Photocathodes 4
 
  • V. Bechthold, K. Aulenbacher, M.A. Dehn, S. Friederich
    IKP, Mainz, Germany
  • K. Aulenbacher
    HIM, Mainz, Germany
 
  Funding: BMBF-HOPE II
The interest in multi alkali antimonide photocathodes, e.g. K2CsSb, for future ERL projects like BERLinPro (Berlin Energy Recovery Linac Prototype) and MESA (Mainz Energy-Recovering Superconducting Accelerator) has grown in recent years. In particular for the case of RF-sources the investigation of the time response is of great importance. In Mainz we are able to synthesize these kinds of photocathodes and investigate their pulse response at 1 picosecond level using a radio frequency streak method. We present on the one hand the cathode plant which is used for synthesizing the multi alkali antimonide photocathodes and on the other hand first measurements showing pulse responses of K2CsSb at 400 nm laser wavelength. Furthermore, an analyzing chamber has been installed, which allows investigation of lifetime under laser heating and in-situ measurements of the work function using a UHV Kelvin Probe.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2017-MOPSPP004  
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MOPSPP005 The Small Thermalized Electron Source at Mainz (STEAM) 9
 
  • S. Friederich, K. Aulenbacher
    IKP, Mainz, Germany
 
  Funding: Work supported by BMBF-HOPE II and DFG through RTG 2128.
The Small Thermalized Electron Source at Mainz (STEAM) is a photoelectron source which will be operated using NEA GaAs excited near its band gap with an infrared laser wavelength to reach smallest emittances. CST simulations indicate that emittance growth due to vacuum space charge effects can be controlled up to bunch charges of several tens of pC. The goal of the project is to demonstrate that the intrinsical high brightness can still be achieved at such charges. The current status will be presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2017-MOPSPP005  
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MOPSPP006 SPOCK - a Triode DC Electron Gun With Variable Extraction Gradient 13
 
  • L.M. Hein, K. Aulenbacher, V. Bechthold, M.A. Dehn, S. Friederich, C. Matejcek
    IKP, Mainz, Germany
 
  Funding: German Federal Ministry of Education and Research (BMBF project HOPE-II FKZ 05K16UMA) and the Cluster of Excellence "PRISMA
The electron source concept SPOCK (Short Pulse Source at KPH) is a 100kV DC source design with variable extraction gradient. Due to its triode inspired design the extraction gradient can be reduced for e.g. investigations of cathode physics, but also enhanced to mitigate space charge effects. In the framework of the MESA-Project (Mainz Energy-Recovering Superconducting Accelerator) its design has been further optimized to cope with space charge dominated electron beams. Although it injects its electron beams directly into the LEBT matching section, which excludes any adjustments of the electron spin, the source SPOCK will allow higher bunch charges than the MESA standard source.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2017-MOPSPP006  
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MOPSPP008 Low Energy Beam Transport System for MESA 20
 
  • C. Matejcek, K. Aulenbacher, S. Friederich, L.M. Hein
    IKP, Mainz, Germany
 
  An important part of the new accelerator MESA (Mainz Energy recovering Superconducting Accelerator) is the low energy beam transport system connecting the 100 keV electron source with the injector accelerator. Here the spin manipulation and the bunch preparation for the injector accelerator take place. Due to the low energy, space charge will be an challenging issue in this part. Therefore, start-to-end simulations were done with a combination of the two particle dynamics codes PARMELA* and CST**. At the moment, a test setup is being built up to check the functionality of devices and compare the beam parameters with the simulation. Here the focus lies on the bunch preparation system because at this part we expect high impact of the space charge by reason of the necessary bunch compression. The advance of the test setup, the simulations and measurements done so far will be shown.
* Phase and Radial Motion in Ion Linear Accelerators
** Computer Simulation Technology
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2017-MOPSPP008  
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MOPSPP012
Identification of Ion Bombardment Area on the Photocathode After 900 μA CW Beam Operation at cERL  
 
  • M. Yamamoto, Y. Honda, X.J. Jin, T. Miyajima, T. Obina
    KEK, Ibaraki, Japan
  • Y. Kameta
    e-JAPAN IT Co. Ltd, Hitachi, Japan
  • T. Kawasaki
    Toshiba, Yokohama, Japan
  • N. Nishimori
    QST, Tokai, Japan
  • N. Nishimori
    Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
 
  Compact-ERL (cERL) which is under development as an ERL demonstration machine at KEK succeeded in stable supply of CW beam exceeding 900 uA from a GaAs photocathode mounted on a DC-gun in March 2016. In the case of high current beam operation, the ions generated by collision of the beam and the residual molecules on the beam axis is increase and its flow back to the electron gun. As a result, the quantum efficiency (QE) of the photocathode decreases due to ion bombardment is the main factor of determining the cathode lifetime. After the CW operation of the accumulated extracted charge of ~10 Coulomb, steady decrease in QE due to ion bombardment has not yet been clearly confirmed. In order to analyze the area damaged by ion bombard, 2D QE distribution (QE map) measurement system was newly installed in the cathode preparation system. From QE map analysis before and after the CW operation, we confirmed two types of QE decrease. The area about 2 mm diameter near the center of the photocathode that the QE recovery is insufficient by the reactivation process is presumed the damage by ion bombardment.  
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MOPSPP015 Development of a Multialkali Photocathode DC Gun for High Current Operation 29
THICCC003   use link to see paper's listing under its alternate paper code  
 
  • N. Nishimori
    Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
  • R. Hajima, R. Nagai, M. Sawamura
    QST, Tokai, Japan
 
  Funding: This work is partially supported by a JSPS Grant-in-Aid for Scientific Research in Japan (15K13412).
We have developed a DC gun test stand at National Institutes for Quantum Radiological Science and Technology (QST) for high current electron beam generation. The gun test stand consists of an alkali antimonide photocathode preparation chamber, a DC gun with a 250kV-50mA Cockcroft Walton high voltage power supply, and beam line with a water cooled beam dump to accommodate 1.5 kW beam power. We successfully fabricated a Cs3Sb photocathode with quantum efficiency of 5.8 % at 532 nm wavelength and generated 150 keV beam with current up to 4.3 mA with 500 mW laser at 532 nm wavelength. Unfortunately, we encountered a vacuum incident during beam transport of high current beam and the development has been halted. We will fix the vacuum problem and restart the gun development as soon as possible.
 
slides icon Slides MOPSPP015 [22.134 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2017-MOPSPP015  
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MOPSPP016
Discharge Mechanism of Ultra-High Vacuum Gap Derived From the HV Conditioning Result of the cERL DC-Gun  
 
  • M. Yamamoto
    KEK, Ibaraki, Japan
  • N. Nishimori
    QST, Tokai, Japan
  • N. Nishimori
    Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
 
  Funding: JSPS Grant-in-Aid for Scientific Research in Japan (15H0359, 16K05385)
Development of a high brightness electron beam source is indispensable for realizing high repetition X-FEL and CW EUV-FEL as a next generation light source. The high voltage (HV) DC-gun that realized acceleration voltage of > 500 kV and electric field of > 5 MV/m is one of the candidates. In order to stably DC-gun operation, the HV conditioning process is an essential step as preparation of DC-gun operation. The HV conditioning was carried out on compact-ERL (cERL) electron gun and clarified the following four points. i) The voltage at which discharge stops (discharge stop voltage) exists, ii) The discharge stop voltage increases almost continuously with the number of discharges, iii) The gas released at the occurrence of discharge is almost proportional to the difference between the discharge start voltage and the discharge stop voltage, iv) The hold-off time of the voltage is very long under the discharge stop voltage. We focused on the electron stimulated desorption (ESD) phenomenon occurring at the anode can explain these phenomena in a consistent and considered the mechanism of discharge generation in DC field and HV conditioning progression in ultrahigh vacuum (UHV).
 
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MOPSPP017
Energy Distribution and Work Function Measurements for Metal Photocathodes With Measured Levels of Surface Roughness  
 
  • T.S. Beaver, L.B. Jones, B.L. Militsyn, T.C.Q. Noakes, R. Valizadeh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • S. Mistry
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
 
  Funding: The work is part of EuCARD2, partly funded by the European Commission, GA 312453. Funded by the Science and Technology Facilities Council.
The minimum achievable emittance in an electron accelerator depends strongly on the intrinsic emittance of the photocathode electron source which is measureable as the mean longitudinal and transverse energy spreads in the photoemitted electrons. Reducing emittance in an accelerator driving a Free Electron Laser (FEL) delivers significant reduction in the saturation length for an X-ray FEL, reducing machine cost and increasing X-ray beam brightness. There are many parameters which affect the intrinsic emittance of a photocathode. Surface roughness is a significant factor*, and consequently the development of techniques to manufacture low roughness photocathodes with optimum emission properties is a priority for the electron source community. In this work, we present transverse energy distribution and work function measurements made using our TESS facility** for electrons emitted from copper and molybdenum photocathodes with differing levels of measured surface roughness.
* Proc. FEL '06, THPPH013, 583586
** Proc. FEL '13, TUPPS033, 290293
 
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WEICCC001
Commission Results of the Compact ERL High Voltage DC Gun  
 
  • N. Nishimori
    Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
  • R. Hajima, R. Nagai
    QST, Tokai, Japan
  • Y. Honda, X.J. Jin, T. Miyajima, T. Obina, T. Uchiyama, M. Yamamoto
    KEK, Ibaraki, Japan
  • M. Kuriki
    HU/AdSM, Higashi-Hiroshima, Japan
 
  Funding: This work is partially supported by JSPS Grant-in-Aids for Scientific Research in Japan (15H03594, 16K05385).
Beam commissioning of the compact ERL (cERL) has been performed for the next generation ERL light sources such as a laser Compton gamma-ray source and a high power FEL for EUV lithography. The operational high voltage of the cERL DC gun has been limited to 390 kV due to failure of the ten segmented insulators. In November 2015, we installed an additional two segmented insulators on the top of the existing ten segmented insulators. In December 2015, we successfully performed high voltage conditioning up to 500 kV. We also found high voltage threshold for stable operation in a dc electron gun [1]. The cERL operational voltage has been 450 kV in maximum since then. We will present details of the high voltage upgrade and operational status at 450 kV of the cERL gun.
[1] Masahiro Yamamoto and Nobuyuki Nishimori, APL 109, 014103 (2016).
 
slides icon Slides WEICCC001 [6.787 MB]  
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WEICCC002
The ALICE ERL - DC Photocathode Gun Commissioning  
 
  • L.B. Jones
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
 
  The ALICE (Accelerators and Lasers In Combined Experiments) accelerator was the first ERL to be operated in Europe. ALICE was used to drive the UK's first Free-Electron Laser, generating infra-red light in the 4 - 20 micron range which was used in the development of pioneering cancer diagnostics. This talk will present an overview of the ALICE DC GaAs photocathode gun, and review the measured performance of the gun when it was operated in to a dedicated diagnostics beamline.  
slides icon Slides WEICCC002 [61.715 MB]  
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WEICCC003
Injector Challenges for CBETA Demonstration Experiment  
 
  • K.W. Smolenski
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  Funding: This work was performed with the support of NYSERDA (New York State Energy Research and Development Agency) and of the National Science Foundation (Award No. NSF-DMR 0807731).
CBETA, currently under construction, is a 4-pass, 40mA 150MeV ERL based on the proven Cornell ERL injector chain mated with an FFAG loop. The Cornell ERL injector program, originally intended for a large scale X-Ray light source, has been under development and operated for over 10 years. The status of the Cornell ERL injector is reviewed and its parameters compared with the challenges presented by the requirements for CBETA operation. The injector consists of a high voltage DC photocathode gun, a normal conducting buncher cavity, the superconducting injector cryomodule, followed by a splitter magnet that can transport the beam into either a diagnostics beamline or merge the beam into the CBETA ERL loop. The current status of the Cornell DC gun development program and its history will be reviewed. The performance of the injector cryomodule, capable of accelerating beams to 15MeV, will be discussed with a focus on the lessons learned from its operation. Finally the diagnostics beamline and the merger will be detailed along with the latest results from our low emittance beam studies.
 
slides icon Slides WEICCC003 [38.149 MB]  
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WEICCC004 First Results of Commissioning DC Photo-Gun for RHIC Low Energy Electron Cooler (LEReC) 65
 
  • D. Kayran, Z. Altinbas, D. Bruno, M.R. Costanzo, A.V. Fedotov, D.M. Gassner, X. Gu, L.R. Hammons, P. Inacker, J.P. Jamilkowski, J. Kewisch, C.J. Liaw, C. Liu, K. Mernick, T.A. Miller, M.G. Minty, V. Ptitsyn, T. Rao, J. Sandberg, S. Seletskiy, P. Thieberger, J.E. Tuozzolo, E. Wang, Z. Zhao
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
Non-magnetized bunched electron cooling of ion beams during low energy RHIC operation requires electron beam energy in the range of 1.6-2.6 MeV, with an average current up to 45 mA, very small energy spread, and low emittance. A 400 kV DC gun equipped with a photocathode and laser system will provide a source of high-quality electron beams. During DC gun test critical elements of LEReC such as laser beam system, cathode exchange system, cathode QE lifetime, DC gun stability, beam instrumentation, the high-power beam dump system, machine protection system and controls has been tested under near- operational conditions [1]. We present the status, experimental results and experience learned during the LEReC DC gun beam testing.
[1] D. Kayran et al., DC Photogun Gun Test for RHIC Low Energy Electron Cooler (LEReC), NAPAC2016 proceedings, WEPOB54.
 
slides icon Slides WEICCC004 [20.769 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2017-WEICCC004  
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WEIDCC001
The Development of the DC-SRF Photoinjector at Peking University  
 
  • H.M. Xie, W. Cheng, L.W. Feng, J.K. Hao, S. Huang, L. Lin, K.X. Liu, W. Qin, S.W. Quan, F. Wang, F. Zhu
    PKU, Beijing, People's Republic of China
 
  Stable operation of the DC-SRF photoinjector has been realized and the electron beam has been delivered to a 2 × 9-cell SRF linac for further acceleration and terahertz superrandiant undulator radiation experiments. In this talk we will present our latest experiment progress and recent work for decreasing the immitance of the DC-SRF photoinjector. The purpose is to build an upgraded DC-SRF photoinjector capable of driving CW X-ray free-electron lasers.  
slides icon Slides WEIDCC001 [7.812 MB]  
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WEIDCC002
High Charge High Current Beam From BNL 113 MHz SRF Gun  
 
  • I. Pinayev, Z. Altinbas, S.A. Belomestnykh, I. Ben-Zvi, K.A. Brown, J.C.B. Brutus, A.J. Curcio, L. DeSanto, A. Di Lieto, C. Folz, D.M. Gassner, M. Harvey, T. Hayes, R.L. Hulsart, P. Inacker, J.P. Jamilkowski, Y.C. Jing, D. Kayran, R. Kellermann, R.F. Lambiase, D. Lehn, V. Litvinenko, C. Liu, G.J. Mahler, M. Mapes, K. Mernick, R.J. Michnoff, T.A. Miller, M.G. Minty, G. Narayan, P. Orfin, M.C. Paniccia, D. Phillips, T. Rao, T. Roser, S.K. Seberg, B. Sheehy, J. Skaritka, L. Smart, K.S. Smith, V. Soria, Z. Sorrell, R. Than, C. Theisen, P. Thieberger, J.E. Tuozzolo, J. Walsh, E. Wang, G. Wang, D. Weiss, B. P. Xiao, T. Xin, W. Xu, A. Zaltsman, Z. Zhao
    BNL, Upton, Long Island, New York, USA
  • K. Mihara
    Stony Brook University, Stony Brook, USA
  • I. Petrushina
    SUNY SB, Stony Brook, New York, USA
  • K. Shih
    SBU, Stony Brook, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
We are commissioning the accelerator for the Coherent Electron Cooling Proof-of-principle (CeC PoP) Experiment. The 113 MHz superconducting RF gun with Cs2KSb photocathode serves as a source of the electrons. The gun is designed to operate up to 5 nC beam with repetition rate of 78 kHz. In the paper we present status of the gun as well as achieved beam parameters. The photocathode performance (quantum efficieny, lifetime) is also discussed.
 
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WEIDCC003
Metal and Semiconductor Photocathodes in the HZDR SRF Gun  
 
  • J. Teichert, A. Arnold, P.N. Lu, P. Murcek, H. Vennekate, R. Xiang
    HZDR, Dresden, Germany
 
  The superconducting RF photoelectron gun at the ELBE accelerator facility is a high-repetition rate electron injector for CW operation and can provide high average current and high brightness electron beams. During commissioning and operating time different types of photocathodes, metallic (Cu, Mg) and semiconductors (Cs2Te), have been used. We present the preparation processes, properties as well as performance and operational experience of the cathodes in the SRF gun. Furthermore, specific issues like cathode cooling, multipacting, and dark current will be discussed.  
slides icon Slides WEIDCC003 [22.113 MB]  
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WEIDCC004
The BERLinPro SRF Photoinjector System - From Design to First RF Commissioning Results  
 
  • A. Neumann
    HZB, Berlin, Germany
 
  Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association
Helmholtz-Zentrum Berlin (HZB) is currently constructing an high average current superconducting (SC) ERL as a prototype to demonstrate low normalized beam emittance of 1 mm·mrad at 100mA and short pulses of about 2 ps. To reach the required beam properties, an SRF based photo-injector system was developed and recently underwent RF commissioning. The medium power prototype- a first stage towards the final high power 100 mA design- presented here features a 1.4 x λ/2 cell SRF cavity with a normal-conducting, high quantum efficiency Cs2KSb cathode, implementing a modified HZDR-style cathode insert. This injector potentially allows for 6 mA beam current and up to 3.5 MeV kinetic energy, limited by the modified twin TTF-III fundamental power couplers. In this contribution an overview of the design approach, cavity production and module assembly up to the first RF commissioning results of the photo-injector module will be presented.
 
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FRIBCC001 ERL17 Workshop, WG1 Summary: Injectors 77
 
  • E. Wang
    BNL, Upton, Long Island, New York, USA
  • K. Aulenbacher
    HIM, Mainz, Germany
 
  The 59th ICFA Advance Beam Dynamics Workshop on Energy Recovery Linacs, hosted by the CERN was held on CERN campus. The working group (WG) 1 ERL injectors focused on high-brightness, high-power CW electron gun and high QE long lifetime semiconductor photocathode. The working group 1 was separated into two sessions: One is electron gun session, which has eight invited talks; another is photocathode session, which has six invited talks and one contributed talk. This report summarizes the state of the art of electron guns and photocathodes discussed in the ERL workshop WG1.  
slides icon Slides FRIBCC001 [3.229 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2017-FRIBCC001  
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