Superconducting Solenoid Magnets for the MuSIC Project

The new muon beamline, MuSIC, is being constructed at the Research Center for Nuclear Physics (RCNP) at Osaka University in Japan. The project utilizes superconducting solenoid magnets to collect pions and to transport muons with the ultimate efficiency by putting pion-production target inside the solenoid magnet. This is the first of such a novel method to produce intense muon beams. All the superconducting coils are cooled with conduction cooling using Gifford-McMahon cryocoolers. A large superconducting coil with the diameter of 90 cm encloses the pion-production target and thick shielding to protect the coil against severe radiation from the target, so that energy deposit by particles on the coil should be less than 1 W. Pions are captured in a 3.5 T magnetic field and are injected into the subsequent toroidal magnets with the magnetic field of 2 T. Superconducting dipole coils are equipped on each solenoid coil of the transport solenoid to correct the particle trajectory in the toroidal field. The design and construction status of the solenoid channel are described in this paper.