Status of LIU (LHC Injector Upgrade) RF collaboration (3). Irradiation test of GaN solid-state amplifier

J-PARC RF group has been collaborating with CERN to replace ferrite-loaded cavities in the PS Booster by wide-band ones as one item of the LHC Injector Upgrade Project (LIU) for high luminosity LHC (HiLimi). All replacements were completed in the long shut down, LS2. The booster beam energy increased to 2 GeV from 1.4 GeV. Accelerated beam was transfered to SPS after the acceleration to 26 GeV at the PS. We also cooperate to develop Gallium Nitride solid-state amplifier to improve the feedback gain at the PS accelerating cavity system. The solid-state amplifier should be rad-hard because it will be located near the cavity to obatain high feedback gain to compensate a heavy beam loading. Irradiation test of the amplifier was carried out under a mixed-field radiation area downstream of a beam collimator in the J-PARC main ring. Although total dose of 18 kGy (1.8 Mrad) and 2.3 x 10¹⁴ n/cm² were irradiated, the amplifier was stable and same amplification gain. (author)