Beam dynamics, extreme beams, sources and beam related technologies
Electron and ion sources, guns, photo injectors, charge breeders
Paper Title Page
WE1A03 Latest Results of CW 100 mA Electron RF Gun for Novosibirsk ERL Based FEL 598
 
  • V. Volkov, V.S. Arbuzov, E. Kenzhebulatov, E.I. Kolobanov, A.A. Kondakov, E.V. Kozyrev, S.A. Krutikhin, I.V. Kuptsov, G.Y. Kurkin, S.V. Motygin, A.A. Murasev, V.K. Ovchar, V.M. Petrov, A.M. Pilan, V.V. Repkov, M.A. Scheglov, I.K. Sedlyarov, S.S. Serednyakov, O.A. Shevchenko, S.V. Tararyshkin, A.G. Tribendis, N.A. Vinokurov
    BINP SB RAS, Novosibirsk, Russia
 
  Continuous wave (CW) 100 mA electron rf gun for injecting high-quality 300-400 keV electron beam to the Energy Recovery Linac (ERL) driving the Novosibirsk Free Electron Laser (FEL) was developed, built, and commissioned in a diagnostics beam line. The rf gun consists of normal conducting 90 MHz rf cavity with a gridded thermionic cathode unit. Tests of the rf gun confirmed its design performance in strict accordance with numerical simulations. The gun was tested up to the design specifications at a test bench that includes a diagnostics beam line. The design features of different components of the rf gun are presented. The commissioning experience is discussed. The latest beam results are reported.  
slides icon Slides WE1A03 [2.829 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-WE1A03  
About • paper received ※ 14 September 2018      issue date ※ 18 January 2019  
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TH2A03
Intense Beam Generation with 2.45GHz Ion Sources for High Current Linacs  
 
  • S.X. Peng
    PKU, Beijing, People’s Republic of China
 
  The constant need for higher beam intensity of single charged ion beams is a strong motivation to investigate 2.45GHz electron cyclotron resonance (ECR) ion source. It has been chosen by many constructed and constructing facilities such as LEDA, IFMIF, SPIRAL2, SARAF, FAIR, ESS, PKUNIFTY, CADS as H+/D+ beam generator. In this paper, a review of its present status will be given. The key issues for a 2.45GHz ECR ion source development will be described. The permanent magnet ECR build by Peking University (PKU) will be displayed as an example.  
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THPO116 Space-Charge Dominated Photoemission in High Gradient Photocathode RF Guns 941
THOP11   use link to see paper's listing under its alternate paper code  
 
  • Y. Chen, P. Boonpornprasert, J.D. Good, M. Groß, H. Huck, I.I. Isaev, D.K. Kalantaryan, C. Koschitzki, M. Krasilnikov, O. Lishilin, G. Loisch, D. Melkumyan, R. Niemczyk, A. Oppelt, H.J. Qian, Y. Renier, F. Stephan
    DESY Zeuthen, Zeuthen, Germany
  • H. Chen, Y. C. Du, W.-H. Huang, C.-X. Tang, Q.L. Tian, L.X. Yan
    TUB, Beijing, People’s Republic of China
  • H. De Gersem, E. Gjonaj
    TEMF, TU Darmstadt, Darmstadt, Germany
  • M. Dohlus
    DESY, Hamburg, Germany
  • S. A. Schmid
    Institut Theorie Elektromagnetischer Felder, TU Darmstadt, Darmstadt, Germany
 
  The cathode emission physics plays a crucial role in the overall beam dynamics in the gun. Interplays between intricate emission mechanisms in the cathode vicinity strongly influence the cathode quantum efficiency (QE) and the intrinsic emittance. The presence of strong space-charge effects in high gradient RF guns further complicates the emission process. A proper modeling of photoemission and a careful treatment of the space-charge contribution is thus of great necessity to understanding the formation of the beam slice emittance. In this article, emission measurements are carried out using the L-band cesium-telluride photocathode RF gun at the Photo Injector Test Facility at DESY in Zeuthen (PITZ) and the S-band copper photocathode RF gun at Tsinghua University. Following the Dowell model a simple so-called space-charge iteration approach is developed and used to determine the QE through temporal and spatial-dependent electromagnetic fields. An impact of the space-charge cooling on the thermal emittance is presented. Measurement data are shown and discussed in comparisons to preliminary simulation results.  
slides icon Slides THPO116 [6.249 MB]  
poster icon Poster THPO116 [3.157 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO116  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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THPO117
96Zr Beam Acceleration for Isobar Experiment in RHIC  
THOP12   use link to see paper's listing under its alternate paper code  
 
  • M. Okamura, E.N. Beebe, S. Ikeda, T. Kanesue, D. Raparia
    BNL, Upton, Long Island, New York, USA
  • H. Haba
    RIKEN Nishina Center, Wako, Japan
 
  Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
To investigate chiral magnetic effect, 96Zr and 96Ru beams have been accelerated at relativistic heavy ion collider (RHIC) in Run18 at Brookhaven National Laboratory (BNL). 96Zr and 96Ru beams were provided from electron beam ion source (EBIS) injector and tandem Van de Graaff, repectively. In the presentation, 96zr beam production and acceleration will be reported. The EBIS injector consist of laser ion source, EBIS as a charge breeder, 300 keV/u RFQ and 2 MeV/u IH-DTL. The natural abundance of 96Zr is only 2.8 % and about 50 % is occupied by 90Zr. To obtain sufficient beam current, mass number 96 enriched material was used. Unfortunately, only available form of the enriched material is oxide powder which does not suit for laser ion source target. We have established sintering technique of ZrO2 powder to make a solid piece which can be installed into the laser ion source. The induced singly charged Zr and oxygen were delivered to the EBIS to be ionized further. We have optimized laser irradiation condition, EBIS confinement time, operating condition of the linacs to maximized the performance of the linac based injector. The detailed R&D works will be presented in the conference.
 
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THPO118 Beam Transverse Coupling and 4D Emittance Measurement Simulation Studies for PITZ 945
 
  • Q.T. Zhao, M. Krasilnikov, H.J. Qian, F. Stephan
    DESY Zeuthen, Zeuthen, Germany
  • Q.T. Zhao
    IMP/CAS, Lanzhou, People’s Republic of China
 
  The Photo Injector Test Facility at DESY, Zeuthen site (PITZ) was built to test and optimize high brightness electron sources for Free Electron Lasers (FELs) like FLASH and the European XFEL. Although the beam emittance has been optimized and experimentally demonstrated to meet the requirements of FLASH and XFEL, transverse beam asymmetries were observed during operation of the RF guns. Based on previous studies [1], the beam asymmetries most probably stem from beam transverse coupling by quadrupole field errors in the gun section. A pair of normal and skew gun quadrupoles was successfully used for reducing the beam asymmetries in experiment. In this paper, we discuss the beam transverse coupling between X and Y planes due to quadrupole field errors and its impact onto horizontal and vertical rms emittance. Multi-quads scan and two quads with rotated slits scan were proposed to measure the 4D beam matrix for PITZ and tested by simulation, which will give the residual beam coupling after gun quadrupoles compensation and would be helpful for minimizing the 2D rms emittance experimentally.  
poster icon Poster THPO118 [1.521 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO118  
About • paper received ※ 08 September 2018      issue date ※ 18 January 2019  
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THPO124 Design of Pulsed HV and RF Combined Gun System Using Gridded Thermionic-Cathode 949
 
  • T. Asaka, H. Tanaka
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  • Y. Otake
    JASRI, Hyogo, Japan
  • T. Taniuchi
    JASRI/SPring-8, Hyogo-ken, Japan
 
  In recent state-of -arts accelerators like an X-ray free electron laser, the electron beam performance of a linear accelerator demands a low emittance of ~ 2mm mrad. To obtain the low-emittance, such a 500kV thermionic-gun at SACLA and a photocathode rf gun generating 0.5~1MeV electron beams had been developed. Although the photocathode rf gun is compact, it is necessary to prepare a highly stabilized, large and complicated laser system. The 500-kV thermionic-gun of SACLA injector has also to prepare a technically difficult and large high voltage system. Hence, we propose a low-emittance gun system with a low-voltage and grid-loaded 50kV thermionic gun and a 238MHz rf cavity to overcome the complicated difficulty, as extension of the established technology. This system quickly accelerates the electron up to 500keV to preserve the low emittance and to cancel a grid focusing effect by the space charge force of the beam. By using a particle tracking code, we obtained the optimum voltage parameters of the grid and the 238MHz rf for obtaining the above-mentioned low emittance. In this paper, we present a numerical feasibility study to realize the low-emittance gun system.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO124  
About • paper received ※ 10 September 2018      issue date ※ 18 January 2019  
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THPO125 Runing Status of SRF Gun II at the ELBE Radiation Center 952
 
  • R. Xiang, A. Arnold, P.N. Lu, P. Murcek, J.S. Schaber, J. Teichert, H. Vennekate, P.Z. Zwartek
    HZDR, Dresden, Germany
 
  Funding: The work is supported by the German Federal Ministry of Education and Research (BMBF) grant 05K12CR1 and the Deutsche Forschungsgemeinschaft (DFG) grant XI106/2-1.
As a new electron source with higher brilliance, the second version of the superconducting RF photoinjector (SRF Gun II) has been successfully commissioned at the ELBE Center for High-Power Radiation Sources since 2014. SRF Gun II features an improved 3.5-cell niobium cavity as well as a superconducting solenoid in the same cryomodule. For user operation the SRF Gun II with Mg photocathode successfully generated stable beam with bunch charges up to 200 pC in CW mode, and with sub-ps bunch length. In this presentation the gun’s status and beam parameters will be presented.
 
poster icon Poster THPO125 [1.520 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO125  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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THPO126 Compact H+ ECR Ion Source with Pulse Gas Valve 955
SPWR037   use link to see paper's listing under its alternate paper code  
 
  • Y. Takeuchi, Y. Iwashita, H. Tongu
    Kyoto ICR, Uji, Kyoto, Japan
 
  We are developing a compact ECR H+ ion source with pulse gas valve. In the case of high current ion linac, the distance between the ion source and the first accelerating tube such as RFQ must be as short as possible to reduce the space charge effect, while operating in a high electric field a good vacuum condition is desirable. Since hydrogen gas always flows out from ion sources if the plasma chamber is filled with the gas, vacuum pumping systems have to evacuate the gas enough before the first accelerating tube. The pulse gas injection system achieved by a fast piezo gas valve can reduce the gas load on the vacuum evacuation system and is suitable for installing the ion source close to the RFQ.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO126  
About • paper received ※ 19 September 2018      issue date ※ 18 January 2019  
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THPO127 The Effect of Energy Fluctuation on the Multi-bunch Acceleration in E-driven ILC Positron Source 958
 
  • M. Kuriki, H. Nagoshi
    HU/AdSM, Higashi-Hiroshima, Japan
  • S. Kashiwagi
    Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
  • K. Negishi
    Iwate University, Morioka, Iwate, Japan
  • T. Okugi, T. Omori, M. Satoh, Y. Seimiya, J. Urakawa, K. Yokoya
    KEK, Ibaraki, Japan
  • Y. Sumitomo
    LEBRA, Funabashi, Japan
  • T. Takahashi
    Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
 
  E-Driven method is a technical backup for positron source for ILC. In the positron source, the positron is generated and accelerated in a multi-bunch format with gaps in a macro-pulse. We employ AM (Amplitude Modulation) to suppress the transient beam-loading, but a small fluctuation is still expected, depending on the compensation accuracy. In this article, the positron yield which is ratio of numbers of positrons over electrons, is evaluated as a function of the compensation accuracy. With this result and the detail investigation of the beam loading compensation accuracy by AM, the positron yield of E-Driven Positron source for ILC is evaluated.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO127  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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