Comparison of the residual doses before and after resumption of user operation in J-PARC RCS

Yamamoto, Kazami   ; Hayashi, Naoki  ; Hotchi, Hideaki  ; Saha, P. K.   ; Harada, Hiroyuki  ; Yoshimoto, Masahiro  ; Kinsho, Michikazu  ; Saeki, Riuji; Hatakeyama, Shuichiro; Kato, Shinichi*

J-PARC Facilities were seriously damaged by the Great East Japan Earthquake in March 2011, but all facilities resumed a beam operation from December 2012. Beam commissioning results indicated that the beam loss and the residual dose at injection area in the RCS was reduced to 10% of before earthquake. This result owed to new collimator at injection area. The losses and residual doses of other area were almost same as before earthquake.