R&D of residual gas beam profile monitor

We have studied the residual gas beam profile monitor (RCBPM) for the J-PARC neutrino beamline, here the micro channel plate (MCP) is used as a read out device. We carried out the beam tests at the KEK-PS beamline to study the basic performance of the monitor. To check the capability of beam-profile measurement, we studied the properties of signal timing and the effect of electric field produced by the proton beam. We found that the ion collection is effective to avoid the beam induced background in a high beam background environment, and RGBPM works under the electric field produced by the beam itself of less than 20 kV/m. In addition, the gain calibration method of MCP has been developed using thermal electrons from the glowing wire. We found the gain of MCP is calibrated with an accuracy of better than 5%.