title: Stable top-up operation at SPring-8.
abstract: 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.
authors.affiliation: Japan Synchrotron Radiation Research Institute/SPring-8, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan. tanaka@spring8.or.jp
authors.forename: Hitoshi
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authors.lastname: Tanaka
authors.forename: Masatoshi
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authors.lastname: Adachi
authors.forename: Tsuyoshi
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authors.lastname: Aoki
authors.forename: Takao
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authors.lastname: Asaka
authors.forename: Alfred
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authors.forename: Shin
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authors.lastname: Daté
authors.forename: Kenji
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authors.lastname: Fukami
authors.forename: Yukito
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authors.forename: Hirofumi
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authors.lastname: Kimura
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authors.forename: Toshiaki
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authors.lastname: Kobayashi
authors.forename: Shinji
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authors.lastname: Kohara
authors.forename: Noritaka
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authors.lastname: Kumagai
authors.forename: Mitsuhiro
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authors.lastname: Masaki
authors.forename: Takemasa
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authors.lastname: Masuda
authors.forename: Sakuo
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authors.lastname: Matsui
authors.forename: Akihiko
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authors.lastname: Mizuno
authors.forename: Takeshi
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authors.lastname: Nakamura
authors.forename: Takeshi
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authors.lastname: Nakatani
authors.forename: Takashi
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authors.lastname: Noda
authors.forename: Toru
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authors.lastname: Ohata
authors.forename: Haruo
authors.initials: H
authors.lastname: Ohkuma
authors.forename: Takashi
authors.initials: T
authors.lastname: Ohshima
authors.forename: Masaya
authors.initials: M
authors.lastname: Oishi
authors.forename: Sigeki
authors.initials: S
authors.lastname: Sasaki
authors.forename: Jun
authors.initials: J
authors.lastname: Schimizu
authors.forename: Masazumi
authors.initials: M
authors.lastname: Shoji
authors.forename: Kouichi
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authors.lastname: Soutome
authors.forename: Motohiro
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authors.lastname: Suzuki
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Suzuki
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Shirou
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authors.lastname: Takano
authors.forename: Masaru
authors.initials: M
authors.lastname: Takao
authors.forename: Takeo
authors.initials: T
authors.lastname: Takashima
authors.forename: Hideki
authors.initials: H
authors.lastname: Takebe
authors.forename: Akihisa
authors.initials: A
authors.lastname: Takeuchi
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Tamura
authors.forename: Ryotaro
authors.initials: R
authors.lastname: Tanaka
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Taniuchi
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Taniuchi
authors.forename: Kouji
authors.initials: K
authors.lastname: Tsumaki
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yamashita
authors.forename: Kenichi
authors.initials: K
authors.lastname: Yanagida
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Yoda
authors.forename: Hiroto
authors.initials: H
authors.lastname: Yonehara
authors.forename: Tetsuhiko
authors.initials: T
authors.lastname: Yorita
authors.forename: Masamichi
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authors.lastname: Yoshioka
authors.forename: Masaki
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authors.lastname: Takata
mesh_terms: D004583:Electrons; D004867:Equipment Design; D006358:Hot Temperature; D008280:Magnetics; D009991:Oscillometry; D010315:Particle Accelerators; D012542:Scattering, Radiation; D012822:Silicon Dioxide; D017356:Synchrotrons; D013696:Temperature; D013997:Time Factors; D014965:X-Rays
chemical_list: D012822:Silicon Dioxide