Cryostat for the SSC Superferric Magnet Option

Abstract

The superferric magnet option for the SSC requires approximately 160 km of magnets. In order to reduce the number of field connections, it is proposed to use 150 metre long magnet assemblies. Each of these assemblies contains four dipole magnets of 35 metre length, one quadrupole magnet, trim coils and a piping and wire assembly which provides the capability of taking up 45 centimeters of thermal contraction. The cryostat contains the magnet vessel, a couple of heat intercepting shields, superinsulation and pipes carrying refrigerant to and from the refrigerators, located at approximately 6.5 km intervals. The magnet vessel contains the iron laminations, beam tubes, helium channels, busbars and magnets. Weight of the magnet vessel assembly is of the order of 240 kg per metre of length. A large number of problems need to be solved in the cryostat design. Because of cost, available space for the cryostat is limited. Cooldown of the system requires flow channels of large cross- section. Removal of synchrotron radiation during steady state requires high flowrates in the area of the beam tube, where space is limited. Fast warmup and cooldown in local areas is required to repair and/or replace faulty magnets. Non uniform cooling will result in bowing. Beam tube vacuum requires special consideration when pumping kilometers of small diameter tubes. Aligning magnets after installation in the tunnel requires knowledge of the location of the magnet assembly in a cryostat.

Work supported by U.S. Department of Energy