J-PARC Muon Facility, MUSE

Abstract

Abstract The muon science facility (MUSE) is located in the Materials and Life Science Facility (MLF), which is a building integrated to include both neutron and muon science programs. For Phase 1, we succeeded in installing one super conducting decay/surface muon beamline, so called D-line, with a modest-acceptance pion injector of about 45 mSr in the summer of 2008. In November 2009, by iterative beam tuning and developing new beamline elements such as a larger separator, the surface muons (μ +) extraction rate was significantly increased up to 1.8 × 106/s with the use of a 120 kW proton beam from the RCS. The achieved intensity is equivalent or even larger than that at the RIKEN-RAL muon facility, and would correspond to 1.5 × 107/s surface muons when in the future the proton beam will reach a power of 1MW. Recently, the Superomega muon beamline, so called U-line, with a large acceptance of 400 mSr was funded for construction, delivering 4 × 108/s surface muons to the experimental area, aiming at creating a new type of muon source; an intense ultra-slow muon source of 1 × 105-6/s for the study of thin film magnetism, etc.