Author: Sawamura, M.
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Resonance Control at the Compact ERL in KEK  
  • T. Miura, D.A. Arakawa, M. Egi, K. Enami, T. Furuya, E. Kako, H. Katagiri, T. Konomi, T. Matsumoto, S. Michizono, F. Qiu, H. Sakai, K. Umemori
    KEK, Ibaraki, Japan
  • N. Liu
    Sokendai, Ibaraki, Japan
  • M. Sawamura
    QST, Tokai, Japan
  The compact energy recovery linac (cERL) in KEK is a test facility for the future 3-GeV ERL light source. The 1.3 GHz superconducting cavities are used in the injector linac cryomodule and the main linac cryomodule. The slide-jack tuner with stepper motor is used for coarse tuning of the resonant frequency, and piezo tuner is used for fine tuning. The digital tuner feedback system based on micro-TCA standard has been employed. The frequency band of the tuner feedback has been set lower than the mechanical resonance frequency. The rf field fluctuation caused by the Michrophonics is compensated by the rf feedback. In the injector linac, one rf source drives two cavities with vector-sum control. The vector-sum calibration error affected the beam energy jitter, but that has been improved after adopting the high gain parameter in resonant frequency feedback in order to keep the field balance of the cavities.  
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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.
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