High‐Intensity Proton Linac for the KEK/JAERI Joint Project

The high‐intensity proton accelerator facility in Japan, comprising a 600‐MeV linac, a 3‐GeV RCS (Rapid‐Cycling Synchrotron), and a 50‐GeV synchrotron, has been officially approved for construction of its Phase I. Phase I includes a 400‐MeV normal‐conducting linac as an injector, which consists of a 3‐MeV RFQ, a 50‐MeV DTL, a 190‐MeV SDTL (Separate‐function DTL), and a 400‐MeV ACS (Annular Coupled Structure linac). The basic design of the injector linac has nearly been completed. In parallel with the design study, the construction of its low‐energy part, which is up to 60 MeV, has been started at KEK to develop and establish the linac system before moving to the JAERI site. In this paper, we present the recent progress in the R&D and construction work together with the outline of the latest linac design.