High voltage dependence measurement of beam loss monitor in J-PARC RCS

Hatakeyama, Shuichiro; Yoshimoto, Masahiro  ; Yamamoto, Kazami   

J-PARC accelerators consist of linear accelerator (LINAC), 3GeV synchrotron (RCS) and main ring synchrotron (MR). RCS is an important facility delivering the beam to Materials and Life Science Experimental Facility (MLF) and MR. In RCS 87 proportional counter type beam loss monitors (PBLM) are installed and it is protecting the equipments on the beam line from the radioactivation by alerting the machine protection system (MPS) when the integrated value of the beam loss in an accelerating cycle gets over the limit. In this presentation, -1000V to -2000V high voltage are adapted to PBLMs and output was measured. In result, some PBLMs where the beam loss is large enough, there are saturations around -1400V to -2000V about the peak value of beam loss but no saturation about integral value of beam loss. Also it is considered the new HV system which solves some issues of the on-going HV system.