Evaluation of characteristics of race-track bellows

Watanabe, Masao  ; Ogiwara, Norio; Sawa, Soji*; Tanaka, Toshihiro*

At the extraction part of J-PARC 3 GeV Rapid Cycling Synchrotron, a race-track bellows between the vacuum chamber of extraction septum magnet 1 and 2 is required, because there is no space to install a circular bellows. However, formed titanium bellows of race-track shape has never been fabricated. Smaller size race-track bellows than that of actual size were fabricated. Characteristics of them were and measured and evaluated. We performed measurements of spring force, expansion/contraction repetition life test, vacuum heating test and He-gas leak test. The characteristics of the race-track bellows are satisfied with our use conditions. It was judged from the above, we obtained prospect that using race-track bellows between the vacuum chamber of extraction septum magnet 1 and 2 is one of the solutions.