Development of a beam induced heat-flow monitor for the beam dump of the J-PARC RCS

A beam induced heat-flow monitor (BIHM) will be installed in front of the beam dump of the RCS (Rapid Cycling Synchrotron) at J-PARC (Japan Proton Accelerator Research Complex), where a power limitation of the beam dump is 4 kW. The purposes of this monitor are to observe a beam current injected into the beam dump and to generate an alarm signal for the main control system of the RCS. At the BIHM the beams penetrate a carbon plate of 1.5 mm in thickness, where the plate is supported by four rods on the monitor chamber. The heat generated by the interactions between the beam and the carbon plate propagates to the outer edge of the plate, and then to the monitor chamber through the four rods. By measuring the temperature differences between upstream and downstream ends of each rod, the total heat flow can be measured. The beam current can be determined by the measured heat flow with the help of the calculated stopping power of a proton in a carbon material. The design of the BIHM and test results will be presented.