CRYOCOOLER-COOLED HIGH-FIELD SUPERCONDUCTING MAGNET

A high field NbTi/Nb3Sn superconducting magnet with no use of liquid h elium was developed by adopting high-T-c Bi2Sr2Ca2Cu3O10 current leads and 4 K GM-cryocoolers. The initial cooldown from room temperature to 4.1 K for the coil was attained within 40 hours by conductively cooli ng in vacuum. The cryocooler-cooled superconducting magnet successfull y achieved to generate a central field of 10.7 T in a 52 mm room tempe rature experimental bore, and to hold a field at 10.5 T for 24 hours.