A DESIGN FOR THE SUPERCONDUCTING OUTSERT OF A 45-T HYBRID MAGNET SYSTEM USING CABLE-IN-CONDUIT CONDUCTORS

A part of the mission of the new National High Magnetic Field Laboratory is to have available for users in 1995 a hybrid magnet system capable of producing at least 45-T steady field on axis in a 33 mm working bore. Approximately 31 T of the combined field will be produced by a water-cooled insert mated to a 24 MW de power supply (upgraded later to 32 MW). The superconducting outsert, which combines NbTi and Nb3Sn conductor technologies, will provide more than 14 T. We describe an option for this superconducting outsert based on the cable-in-conduit-conductor (CICC) approach, wherein cabled strands of conductor are contained in intimate contact with helium coolant inside a strong steel sheath that also acts as distributed structure. A departure from the usual practice for CICC technology is in the application of static HeII cooling, which simultaneously provides higher conductor performance and nearly passive extraction of the rather modest heat loads during normal operation of the magnet system.