Operating modes of the SSC sector station cryogenic system

The magnets in the Collider rings and in the HEB (High Energy Booster) ring are refrigerated by single phase helium flow controlled at a temperature of 4 K to maintain the magnet windings in the superconductive state. To minimize the heat load into the 4 K loop, the magnet cryostats are designed to provide high quality thermal insulation achieved by a high vacuum with multilayer insulation (MLI) and by two thermal shields at nominal temperatures of 84 K and 20 K, respectively. An extensive cryogenic system capable of normal operation of the superconducting magnets and handling transient conditions such as quenches, beam activation, ring filling, and beam ramping is required. The cryogenic system must also have the capability to perform other services such as cleanup, cooldown, and warmup, to allow for maintenance and repair of the superconductive components throughout the ring