The superconducting solenoid magnet system for the GEM detector at the SSC

The design of the magnet for the GEM detector at the SSC is described. It is an 18 m inner diameter, 30 m long superconducting solenoid, with a magnetic field of 0.8 T. The basic solenoidal field is shaped by large ferromagnetic cones, to improve detector performance in the ends of the solenoid. Because of the system's large size and mass, field-fabrication on-site at the SSC is required. The challenges in this process, together with the large stored energy of the system 2.5 GJ, have lead to novel design choices in several areas, including the conductor. The design of the conductor, cold mass, vacuum vessel, cold mass supports, thermal shields, forward field shapers, and auxiliary systems are described. >