Stable top-up operation at SPring-8

Hitoshi Tanaka, Masatoshi Adachi, Tsuyoshi Aoki, Takao Asaka, Alfred Baron, Shin Daté, Kenji Fukami, Yukito Furukawa, Hirofumi Hanaki, Naoyasu Hosoda, Tetsuya Ishikawa, Hiroaki Kimura, Kazuo Kobayashi, Toshiaki Kobayashi, Shinji Kohara, Noritaka Kumagai, Mitsuhiro Masaki, Takemasa Masuda, Sakuo Matsui, Akihiko MizunoTakeshi Nakamura, Takeshi Nakatani, Takashi Noda, Toru Ohata, Haruo Ohkuma, Takashi Ohshima, Masaya Oishi, Sigeki Sasaki, Jun Schimizu, Masazumi Shoji, Kouichi Soutome, Motohiro Suzuki, Shinsuke Suzuki, Yoshio Suzuki, Shirou Takano, Masaru Takao, Takeo Takashima, Hideki Takebe, Akihisa Takeuchi, Kazuhiro Tamura, Ryotaro Tanaka, Yoshihito Tanaka, Tsutomu Taniuchi, Yukiko Taniuchi, Kouji Tsumaki, Akihiro Yamashita, Kenichi Yanagida, Yoshitaka Yoda, Hiroto Yonehara, Tetsuhiko Yorita, Masamichi Yoshioka, Masaki Takata

Research output: Contribution to journalReview articlepeer-review

40 Citations (Scopus)


Top-up operation allows SPring-8 to provide highly stable X-ray beams with arbitrary filling patterns. The implementation of top-up operation is described, with a focus on the simultaneous achievement of stability of stored current, beam orbit, purity of an isolated single bunch, and beam injection efficiency. Stored-current fluctuations have been routinely reduced to a level of 10 -3. Stored-beam oscillation on frequent beam injection, which was originally regarded as the most serious problem, has been successfully suppressed to a sufficiently low level that it never perturbs imaging experiments. Current impurities in nominally empty buckets have been reduced to a level of 10-9 over more than one week of operation, making possible the measurement of time-resolved spectra using high-current bunches. Finally, excellent injection efficiency, higher than 80%, is routinely obtained, even for small undulator gaps, which is critical for preventing radiation damage to insertion-device magnets and to reduce leakage radiation. The process of achieving highly stabilized top-up operation at SPring-8 and its utility for user experiments are described.

Original languageEnglish
Pages (from-to)378-391
Number of pages14
JournalJournal of Synchrotron Radiation
Issue number5
Publication statusPublished - 2006 Sept


  • Heat load
  • Injection-beam loss
  • Purity
  • Stability
  • Thermal equilibrium
  • Top-up operation


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