R&D of Beam Monitors at J-PARC Neutrino Beamline

The T2K experiment is a next generation long baseline neutrino oscillation experiment following the current ongoing K2K experiment in Japan. A high intensity narrow band neutrino beam is produced by a high intensity proton beam. The power of the proton beam in T2K is more than 100 times higher than that in K2K. The superconducting magnets are used to bend the 50GeV proton beam about 80 degrees toward the Super-Kamiokande. To protect the superconducting magnets from quenching, we should control the proton beam precisely. It is also important to keep the proper beam size not to destroy the target. We have to establish the beam tuning scheme with beam monitors. We have carried out the beamline simulations based on Geant4. We check the number and positions of beam monitors to tune the proton beam, and study the emittance measurement scheme. We also study the feasibility of the Residual Gas Beam Profile Monitor (RGBPM) as a proton beam monitor candidate for the J-PARC neutrino beamline. To check the basic performance, we have carried out beam tests at the K2K neutrino beamline and the NML beamline at KEK-PS. We find it is difficult to operate RGBPM under the high beam-induced background environment and high beam-induced electric field.