Large aperture alumina ceramics beam pipe with low spring constant bellows

Kamiya, Junichiro   ; Kinsho, Michikazu  ; Abe, Kazuhiko*; Higa, Kyusaku*; Koizumi, Oji*

The 3 GeV Rapid Cycling Synchrotron aims to generate one of the highest power protons in the world. Beam pipes of alumina ceramics are used to prevent the induced current, which is caused by the rapid change of the magnetic field. In the beam injection section, ceramics beam pipes for a quadrupole magnet and a horizontal shift bump magnet are connected without bellows due to the narrow space. To improve maintainability, the ceramics beam pipes for the quadrupole magnet were newly designed. The end shape of ceramics unit duct was revised and 30 mm length are ensured to insert the bellows. The titanium bellows with low spring constant was successfully developed. Verification test for brazing of newly designed unit ducts and titanium sleeve was performed in order to examine the effect of the unique cross-sectional shape, racket shape fitting into 500 mm due to accept the injection beam and circulating beam passing through the injection quadrupole magnet.