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 18m inner diameter, 30m long superconducting solenoid, with a magnetic field of 0.8T. The basic solenoidal field is shaped by larg e ferromagnetic cones, to improve detector performance in the ends of the solenoid. Because of the system's large size and mass, field-fabri cation 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 lea d to novel design choices in several areas, including the conductor. T he design of the conductor, cold mass, vacuum vessel, cold mass suppor ts, thermal shields, forward field shapers, and auxillary systems are described.