Development of a 15T Cryocooled Superconducting Magnet

Abstract

We have designed and constructed a 15T cryocooled superconducting magnet with a vertical room temperature bore of 52mm. The main components of the magnet are four Nb₃Sn superconducting coils, a NbTi superconducting coil, two pairs of bismuth-based oxide superconducting current leads (Bi2223 current lead) and two Gifford-McMahon (GM) cryocoolers. The coils were directly cooled down from room temperature to 3.6K in 114h by compact GM cryocoolers without liquid helium. The magnet generated a magnetic field of 15.1T at the center of the bore and was excited from 0 to 15.1T in 38min. The magnet succeeded in holding the field at 15.1T for 24h at the constant coil temperature of 3.8K.