Performance of the next-generation LLRF control system for the J-PARC RCS

Tamura, Fumihiko   ; Sugiyama, Yasuyuki*; Yoshii, Masahito*; Yamamoto, Masanobu   ; Okita, Hidefumi  ; Omori, Chihiro*; Nomura, Masahiro  ; Shimada, Taihei ; Hasegawa, Katsushi*; Hara, Keigo*; Furusawa, Masashi*

A stable and precise LLRF (Low Level RF) control system is indispensable for acceleration of high intensity proton beam in the J-PARC RCS. The original LLRF control system had been operated without major problems for more than ten years since the start of operation of the RCS, while maintenance of the system became difficult due to the obsolesce of the old FPGAs in the modules. We developed and installed the next-generation LLRF control system based on MTCA.4. The key function of the system is the multiharmonic vector rf voltage control feedback. We describe the system overview and the commissioning results. The performance of the beam loading compensation is significantly improved.