1. 2) Y. Hikichi and N. Ogiwara: in Proc. 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan, Hiroshima, 2008.
2. 3) N. Ogiwara, M. Kinsho, D. Nishizawa and Y. Saito: in Proc. 10th Meeting on Ultra High Vacuum Techniques for Accelerators and Storage Ring, KEK, Tsukuba, Japan, 2004.
3. 4) H. Kumagai, G. Tominaga, Y. Tuzi and G. Horikoshi: Vacuum Science and Engineering, Syokabo, Tokyo, (1970) p323.