972MHz high power RF sources for J-PARC linac

In the J-PARC Linac, upgrade with the output energy of 400MeV is performed. In this report, we describe overview of the upgrade scheme and the development status of 972MHz high power rf components. In development of 972MHz klystron, we converted no.1 tube into the klystron with a small size output window, and evaluated the characteristics. In klystron power supply, although there was no new development element, the improvement to obtain high reliability was added to the anode modulator. In the modified circulator, VSWR characteristic of satisfying specification was achieved. However, discharge occurred on the ferrite surface at the total reflection test. (author)