Tsumaki, K.

Paper	Title	Page
THPKF038	Radiation Damage of Magnet Coils due to Synchrotron Radiation	2356
	K. Tsumaki, S. Matsui, M. Oishi, T. Yorita JASRI/SPring-8, Hyogo T. Shibata, T. Tateishi KOBELCO, Hyogo
	Radiation damage of the equipment in the SPring-8 storage ring tunnel has become a serious problem. In the storage ring, the unnecessary radiation from bending magnets is shielded by absorbers. The equipment around the absorbers was damaged by the scattered radiation from the absorbers. Last year, cooling water leaked from the rubber hose of magnets. It was due to the deterioration of rubber hose caused by synchrotron radiation. We measured the radiation distribution around the storage ring and found that the most high intensity spot was on the magnet coil near the absorbers. If the coils are damaged and the magnets do not work correctly, we need to shut down the storage ring to exchange the magnet coils. To avoid such a situation, we needed to clarify the relation between the radiation damage of the coils and the dose of radiation. We did an acceleration test of the radiation damage of magnet coils. The magnet coils were exposed to the radiation from the bending magnet directly. We observed the degree of damage with changing the doses of radiation. In this paper, we describe about these acceleration tests and test results.
THOACH03	Top-up Operation at SPring-8 - Towards Maximizing the Potential of a 3rd Generation Light Source	222
	H. Tanaka, T. Aoki, T. Asaka, S. Daté, K. Fukami, Y. Furukawa, H. Hanaki, N. Hosoda, T. Kobayashi, N. Kumagai, M. Masaki, T. Masuda, S. Matsui, A. Mizuno, T. Nakamura, T. Nakatani, T. Noda, T. Ohata, H. Ohkuma, T. Ohshima, M. Oishi, S. Sasaki, J. Schimizu, M. Shoji, K. Soutome, M. Suzuki, S. Suzuki, S. Takano, M. Takao, T. Takashima, H. Takebe, K. Tamura, R. Tanaka, T. Taniuchi, Y. Taniuchi, K. Tsumaki, A. Yamashita, K. Yanagida, H. Yonehara, T. Yorita JASRI/SPring-8, Hyogo M. Adachi, K. Kobayashi, M. Yoshioka SES, Hyogo-pref.
	Top-up operation maximizes research activities in a light source facility by an infinite beam lifetime and photon beam stability. We have been improving the SPring-8 accelerators to achieve the ideal top-up operation. For the perturbation-free injection, we adjusted the magnetic field shape of four bump magnets to close the bump orbit, and introduced a scheme to suppress the stored beam oscillation induced by the nonlinearlity of sextupole magnets. These reduced the horizontal oscillation down to a third of the stored beam size. For the loss-free injection, beam collimators were installed upstream of the injection line. This realized the injection efficiency of ~100% under the restricted gap condition of in-vacuum insertion devices (ID). Since autumn 2003, we have been injecting the beams keeping the photon beam shutters opened and ID gaps closed. We developed a bunch-by-bunch feedback system to reduce the beam loss further with all the ID gaps fully closed by lowering the operating chromaticity. The operation with constant stored current is scheduled in June 2004. We present the overview and progress of the SPring-8 top-up operation focusing on our developments and results.
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