The design and performance of a Bi-2223/Ag magnet cooled by a single-stage cryocooler

The design and fabrication of a split coil Bi-2223/Ag tape superconducting magnet cooled by a single-stage cryocooler is presented. The magnet consists of six double-wound pancakes impregnated by epoxy resin with inner diameter 50 mm and outer diameter 98 mm. Critical currents of individual pancakes, double pancakes and the whole magnet are measured, calculated and discussed. The magnet's performance was tested at liquid helium and nitrogen temperatures as well as at solid nitrogen temperatures and cooled by an AL230 single-stage Gifford-McMahon cycle cryorefrigerator. The measured magnet currents are compared with those estimated by calculations using short sample data.