Y. Ohashi, T. Asaka, H. Ego, M. Hara, Y. Kawashima, T. Ohshima, T. Takashima, H. Yonehara (SPring-8)
The SPring-8 consists of three accelerators: a 1 GeV linac, a booster synchrotron and an 8 GeV storage rings(Sy, SR), which use the common synthesizer of 508.58MHz. A reference signal transmission system relies on the phase stabilized fiber optic link with phase-locking. A specially developed synchronous universal counter(SUC) drastically simplified the beam injection system and other precise timing systems for the user experiments. Single bunch operation was realized by this timing system with a compact RF knock-out system installed in the Sy. Initial single bunch impurity of less than 10 ppb (relative to the main bunch) did not grow during the user beam operation including several beam refills. A time resolved experiment using pulsed laser determined the overall timing precision to less than 5psec for 1~2 hours by streak camera measurement. Changes of 100 nm in the circumference of SR caused by the earth tide are compensated by changing the acceleration frequency. The precision and reliability of our reference and timing systems were verified by above measurements. This paper describes the details of the reference fiber optic link, the precise timing system with emphasis on the SUC, and their performances.
 H. Suzuki et al., '508.58MHz synchronous universal counter for beam control system of SPring-8', Nucl. Instr. and Meth. A 431 (1999)
Last updated: September 13, 2002
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