Status of the J-PARC Ring RF Systems

The high intensity proton accelerator complex (JPARC) consists of the Linac, the 25Hz rapid cycling synchrotron (RCS) and the 50GeV main synchrotron (MR). During the long shutdown of 2013, the Linac energy was upgraded from 181MeV to the design value of 400MeV. In the RCS, we have installed the last 12 th RF system. In operation from January 2014, beam commissioning aimed at 1 MW operation was started. In the MR, the upgrade plan of the beam power, realized by raising the repetition, is now going on. For this reason the accelerating voltage must be increased, and all MR RF systems will be replaced with more efficient systems. A new magnetic alloy material (FT3L) was developed. Manufacturing of the FT3L accelerating cavities has been proceeding. It becomes possible to increase the accelerating voltage from 280 kV to 560 kV, using the new cavities in combination with the existing RF power supplies. We have started the developments of a 2nd harmonic system loaded with aircooled FT3L cores and a high-Q VHF cavity system, too. The VHF system is used for longitudinal dilution and the 2 nd harmonic system increases the bunching factor of the circulating high intensity proton beam.