• H. Ao
  JAEA/LINAC, Ibaraki-ken

The J-PARC (Japan Proton Accelerator Research Complex) accelerator comprises the 400-MeV injector linac (at present 181 MeV), the 3-GeV Rapid-Cycling Synchrotron (RCS) and the 50-GeV Main Ring (MR). The 3-MeV RFQ, the 50-MeV DTL and the 181-MeV Separated-type DTL have been operated in the linac for experimental users. The 400-MeV energy upgrade of the linac started from March 2009. The ACS (Annular Coupled Structure) cavities, the RF sources, the beam monitors and the utilities are in production. Although some components are prepared in the annual summer shutdown separately, the all cavities will be installed and commissioned for 6 months from July 2012. In this paper, we present the current status and the preliminary results of the energy upgrade.