Design of the Large Acceptance Muon Beamline at J-PARC

Abstract

The Materials and Life Science Facility (MLF) is currently under construction at J‐PARC in Tokai, Japan. The muon section of the facility will house the muon production target and four secondary beamlines used to transport the muons into two experimental halls. One of the beamlines is a large acceptance beamline (the so called Super Omega Muon beamline) which, when completed, will produce the largest intensity pulse muon beam in the world. The expected rate of surface muons for this beamline is 5×108 μ+/s, and a cloud muon rate of 107 μ−/s. The extracted muons will be used for projects involving the production of ultra‐slow muons as well as for muon‐catalyzed fusion. The beamline consists of the normal‐conducting capture solenoids, the superconducting curved transport solenoids, and the Dai Omega‐type axial focusing magnet. Currently, the capture and transport solenoids are under design, with the former in its final stages and the latter being finalized for construction of test coils. The design of the Dai Omega‐type axial focusing magnet is under consideration with particular emphasis on its compatibility with the transport solenoids.