Operation and current status of injection, extraction, kicker magnet and the power supply for J-PARC 3 GeV RCS

Watanabe, Masao  ; Hayashi, Naoki  ; Shobuda, Yoshihiro   ; Suganuma, Kazuaki ; Takayanagi, Tomohiro   ; Togashi, Tomohito; Toyama, Takeshi*

Stable operation is required for RCS at J-PARC. In the kicker system at extraction section of RCS, there had been many troubles for unstable operation of the thyratrons switches of the power supply just after 25 pps operation started in February 2009. However, the operation was improved by handling thyratrons in appropriate manner in October 2010. After the grate earthquake on 11 March 2011, injection and extraction magnets, power supplies, cables and bus-duct were checked. The results of the measurements and the checks were all not in the problem. We have to reach extraction beam power of 1 MW in RCS in the near future. Kicker impedance is most severe among other impedance sources. The matching resistor and newly developed diodes are connected at the power supply to reduce the impedance. We confirmed that reduced voltages and stable operation of accelerator.