Author: Matsumura, H.
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TUPOW036 Recent Developments and Operational Status of the Compact ERL at KEK 1835
  • T. Obina, M. Adachi, S. Adachi, T. Akagi, M. Akemoto, D.A. Arakawa, S. Araki, S. Asaoka, M. Egi, K. Enami, K. Endo, S. Fukuda, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, K. Hozumi, A. Ishii, X.J. Jin, E. Kako, Y. Kamiya, H. Katagiri, R. Kato, H. Kawata, Y. Kobayashi, Y. Kojima, Y. Kondo, T. Konomi, A. Kosuge, T. Kume, T. Matsumoto, H. Matsumura, H. Matsushita, S. Michizono, T. Miura, T. Miyajima, H. Miyauchi, S. Nagahashi, H. Nakai, H. Nakajima, N. Nakamura, K. Nakanishi, K. Nakao, K.N. Nigorikawa, T. Nogami, S. Noguchi, S. Nozawa, T. Ozaki, F. Qiu, H. Sagehashi, H. Sakai, S. Sakanaka, S. Sasaki, K. Satoh, Y. Seimiya, T. Shidara, M. Shimada, K. Shinoe, T. Shioya, T. Shishido, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, T. Takenaka, O. Tanaka, Y. Tanimoto, N. Terunuma, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, J. Urakawa, K. Watanabe, M. Yamamoto, N. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida
    KEK, Ibaraki, Japan
  • R. Hajima, M. Mori, R. Nagai, N. Nishimori, M. Sawamura, T. Shizuma
    QST, Tokai, Japan
  • M. Kuriki
    Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
  The Compact Energy Recovery Linac (cERL) at KEK is a test accelerator in order to develop key components to realize remarkable ERL performance as a future light source. After the beam commissioning in December 2013, the legal current limit has been increased step-by-step like 1 uA, 10 uA, and 100 uA. Survey for the source of beam losses has been conducted in each step, and the study on beam dynamics and tuning has also been carried out. As a next step, 1 mA operation is scheduled in February 2016. In parallel to the increase in beam current, a laser Compton scattering (LCS) system which can provide high-flux X-ray to a beamline has been successfully commissioned. We report recent progress in various kinds of beam tuning: improvement of electron gun performance, high bunch charge operation, mitigation of beam losses, LCS optics tuning and bunch compression for THz radiation.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW036  
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TUPOW038 Measurement and Control of Beam Losses Under High Average-current Operation of the Compact ERL at KEK 1839
  • S. Sakanaka, K. Haga, Y. Honda, H. Matsumura, T. Miyajima, T. Nogami, T. Obina, H. Sagehashi, M. Shimada, M. Yamamoto
    KEK, Ibaraki, Japan
  The compact ERL (cERL)* is a superconducting accelerator aimed at demonstrating excellent ERL technologies for the future light source. The cERL comprises a 5 MeV injector, a main linac, and a recirculation loop. In the cERL, production and transportation of low-emittance and high average-current beams (tentative goals: 1 mm-mrad and 10 mA) is primarily important. At this moment (in December 2015), beam currents of up to 80 uA (CW) have successfully been transported through the recirculation loop at a beam energy of 20 MeV. Before such high-current operations, we carefully tuned up the machine so that beam losses became very small. The beam losses were watched using fast beam-loss detectors and radiation monitors while absolute losses were estimated from measured radiation levels on the roof of the shield. After careful beam-optics corrections and elimination of beam halos / tails at low-energy section, we achieved the beam losses of at most a few nA level at several locations along the loop, and those below 1 nA elsewhere in the loop. We will report these results together with the result of higher-current operation which is planned early in 2016.
* S. Sakanaka et al., IPAC'15, TUBC1; T. Obina et al., to be presented at IPAC'16.
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW038  
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WEPOR020 Beam Loss Estimation by Measurement of Secondarily Produced Photons under High Average-current Operations of Compact ERL in KEK 2711
  • H. Matsumura, K. Haga, K. Hozumi, T. Miura, S. Nagaguro, T. Obina, T. Oyama, S. Sakanaka, A. Toyoda
    KEK, Ibaraki, Japan
  • N. Yoshihara
    Tokyo Nuclear Service Co. Ltd., Ibaraki, Japan
  To increase the beam current in the Compact Energy Recovery Linac (cERL) at the High Energy Accelerator Research Organization (KEK), the beam loss must be reduced to less than 0.01% during the transportation of 20 MeV electrons in order to suppress the radiation dose outside the accelerator room. Beam loss locations were successfully identified using the gold activation method, and the beam loss rate was estimated by com-paring the measured dose rate with the simulated dose rate on the roof of the cERL room. Beam operation with beam current of 0.90 mA was achieved with a beam loss rate of less than 0.01%.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR020  
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