Residual doses with 400 MeV injection energy at J-PARC rapid cycling synchrotron

Yamamoto, Kazami   ; Kinsho, Michikazu  ; Hayashi, Naoki  

Last summer shutdown an injection energy of J-PARC rapid cycling synchrotron was upgraded from 181 MeV to 400 MeV to aim for reduction of the space charge effect during injection period. By the commissioning after the shutdown, 300 kW operation condition was established. In this condition, the doses of most areas were kept at the same level as 181 injection energy operation or decreased except to the injection foil chamber, 100 degrees and H dumps.