Study of Irradiation Effects on Thermal Characteristics for COMET Pion Capture Solenoid

A superconducting magnet system for the COMET experiment is now under construction in the Japan Proton Accelerator Research Complex to achieve the most intense negatively charged muon beam in the world. The main part of superconducting magnet system, the Pion Capture Solenoid, will be exposed to the severe irradiation from the production target inside magnets; consequently, superconducting coils will be heated by interactions with the secondary particle. The degradation on thermal conductivity is also expected in these conduction-cooled superconducting coils as the radiation damage can be accumulated in a continuous operation at cryogenic temperature. To investigate the irradiation influence on thermal characteristics of the magnet, a thermal analysis is performed by modeling the three-dimensional structure of the coil with the consideration of irradiation effects. Possible temperature rise in coils with a beam operation is predicted in terms of stability for a continuous operation. In addition, the impact of irradiation effects on the quench protection is discussed in this paper.