Electro-Thermal and Mechanical Analysis of the HTS Split Coil Test Facility for the Muon Collider Cooling Section

Abstract

Within the International Muon Collider Collaboration (IMCC) and the EU funded MuCol programme, a facility was recently proposed to test the breakdown limit of the RF cavities under high magnetic fields (7 T). The magnetic configuration is similar to the one of the muon cooling sections. The LASA laboratory (jointly managed by INFN and University of Milan) in Milan, Italy, is currently working on the magnet design, consisting of a split coil made by high temperature superconductors (HTS) operated at 20 K for energy saving. The coils are of non-insulated type, with a relatively high interturn resistance to limit heating during current ramp up. In the present work, the results of a detailed study on the mechanical design of the HTS split coil support structure are presented together with the coupled electro-thermal analysis of the magnet during the ramp-up transient, optimizing for the coil temperature margins and cryocooler performances. These results will be integrated into a more detailed engineering design which is currently under way, serving as baseline for the construction of the test facility. In case of successful funding round by 2025, the facility could be commissioned by 2027.