Vacuum technologies in the high-power proton beam accelerator: J-PARC

Kamiya, Junichiro   

For vacuum systems in high-power proton accelerators, there are many challenging requirements in addition to their basic role owing to the existence of a large number of high-energy protons, rapid cycling of the magnetic field, and high radioactivation. In addition, it is necessary to promptly evacuate from the atmospheric pressure to UHV and ensure sufficient pumping speed against an additional gas load. The vacuum system of the 3 GeV Rapid Cycling Synchrotron (RCS) at the Japan Proton Accelerator Research Complex fulfills such unique requirements. Many vacuum devices such as turbo molecular pumps with radiation toughness, beam pipes made of alumina ceramics, and titanium beam pipes and bellows were developed in accordance with the design concept of the system. Treatments to minimize both static and dynamic outgassing were also performed, e.g., surface polishing, coating, and vacuum firing. This paper aims to review the vacuum technologies in accelerators taking J-PARC as an example.