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Yorita, T.

 
Paper Title Page
TUOAFI03 Production of MeV Photons by the Laser Compton Scattering Using a Far Infrared Laser at SPring-8 961
 
  • H. Ohkuma, M. Shoji, S. Suzuki, K. Tamura, T. Yorita
    JASRI/SPring-8, Hyogo-ken
  • Y. Arimoto
    Osaka University, Osaka
  • M. Fujiwara, K. Kawase
    RCNP, Osaka
  • K. Nakayama, S. Okajima
    Chubu University, Kasugai, Aichi
 
  In order to produce MeV gamma-ray by the Laser Compton scattering (LCS), a high power optically pumped Far Infrared (FIR) laser has been developed at SPring-8. In the case of the SPring-8 storage ring, the momentum acceptance is so large (± 200 MeV) that the scattered electron is re-accelerated, then the stored beam is not lost by the LCS process. The beam diagnostics beamline is used to inject a FIR laser beam against 8-GeV stored electron beam and to extract MeV gamma-ray produced by LCS. The FIR laser system, gamma-ray production system, and measured gamma-ray spectrum will be presented. Future plans will also be introduced. In order to produce higher intense gamma-ray, we are constructing new gamma-ray production system at another beamline.  
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THPLS034 Top-up Operation of SPring-8 Storage Ring with Low Emittance Optics 3359
 
  • H. Tanaka, N. Kumagai, M. Masaki, S. Matsui, H. Ohkuma, T. Ohshima, M. Oishi, J. Schimizu, K. Soutome, S. Takano, M. Takao, H. Takebe, K. Tsumaki, H. Yonehara, T. Yorita, C. Zhang
    JASRI/SPring-8, Hyogo-ken
 
  We have succeeded in providing stable and three-times more brilliant x-ray to users by combining top-up operation with low emittance optics. The optics with the low emittance of 3nmrad was first applied to the user operation in November 2002. Although the low emittance provided the brilliant x-ray, the extremely short beam lifetime much disturbed the precise experiments. Moreover, the aborted electron beam damaged the part of vacuum chamber at the beam injection section. The low emittance operation was thus suspended in October 2003. By improving design of the vacuum chamber and introducing the top-up injection, the problems for the stable operation were resolved, and then the top-up operation with the low emittance optics has been first achieved at SPring-8. This paper illustrates how we achieved this sophisticated operation by explaining the following three essential investigations: (1) reduction of natural emittance for a storage ring with four magnet-free long straight sections, (2) protection of vacuum chamber from aborted electron beam, and (3) consistency to the top-up operation. The obtained performance is also described in the paper.