Design of the vacuum system of the RIKEN SSC

An acceleration chamber of the IPCR SSC is designed. The operating pressure in the chamber is desirable to be lower than 1 x 10-7 Torr to keep the beam loss less than 10%. The chamber is devided into 8 smaller parts. Two RF resonator sections can be withdrawn backwards from the normal position. Pneumatic expansion seals are used for the sealing between each section. Sub-vacuum chembers enclose the magnet sections to prevent the thin inner walls from collapsing by the large pressure difference. The total outgassing from the chamber walls is estimated to be 11 x 10-3 Torr.l/sec after 20 h pumping. The main pumping systems are composed of the cryo-genic pumps and the turbo-molecular pumps. (author)