Design and Quench Analysis of Superconducting Solenoids for the Lepton Future Circular Collider

As part of the European Strategy for Particle Physics there is an ongoing development towards a Future Circular Collider (FCC-ee) where electron-positron collisions could be used to study the entire electro-weak sector in a low background environment. Particle detectors are used to study these collisions and a strong magnetic field is required to measure the particles’ momenta. Currently, two detector concepts are being studied: the Innovative Detector for Electron-positron Accelerators (IDEA) and the CLIC-Like Detector (CLD). Both these detectors include a superconducting solenoid magnet with a central field of 2 T of which the designs are presented here. The IDEA magnet has an stored magnetic energy density of 14 kJ/kg and in CLD this is 12 kJ/kg. Taking into account their respective free-bore diameters of 4.2 m for IDEA and 7.2 m for CLD this results in very challenging designs for which the mechanical and quench studies are presented. Their results are promising, but extensive R&D; on these magnets would be needed in the future to reach the goals set out in the Conceptual Design Report (CDR).