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- T. Fukui, N. Hosoda, H. Maesaka, T. Ohshima, T. Shintake
RIKEN, Hyogo
- K. Imai, M. Kourogi
OPtical Comb, Inc., Yokohama
- M. K. Kitamura, K. Tamasaku, Y. Otake
RIKEN Spring-8 Harima, Hyogo
- M. Musya
University of electro-communications, Tokyo
- T. Ohata
JASRI/SPring-8, Hyogo-ken
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At SPring-8, the construction of a 5712-MHz linac and undulators as a light source for XFEL is in progress. There are two parts of the linac in accordance with requirements of phase accuracy to realize a stable SASE generation. One is a crest acceleration part using a sinusoidal wave. The other is an off-crest part that corresponds to a bunch compressor giving an energy chirp to a beam bunch. To generate the stable SASE, the beam energy stability of 10-4 is required. To obtain this stability, the accuracy of sub-picoseconds is required in the crest part, and several ten femto-seconds are necessary in the off-crest part. The requirement in the crest part was achieved by rf control instruments based on an electronic circuit in the SCSS prototype accelerator. However, realizing the several ten femto-seconds accuracy is almost impossible by the present electronic circuit technology. Therefore, for overcoming this fact, we employed laser technology. In this paper, we describe a system based on IQ control technology to obtain sub-picoseconds accuracy and an optical signal distribution system using an optical comb generator that could realize several ten femto-seconds accuracy.
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