Oxide Superconducting Current Lead. Various Properties of Bi(2223) Bulk Current Lead and its Application to the Cryocooler Cooled Superconducting Magnet.

The Bi (2223) bulk current lead formed of a thin-walled sintered cylindrical tube has been developed and applied in a cryocooler cooled type superconducting magnet without using liquid helium. The critical current density of the bulk is over 1, 000A/cm2 under self magnetic field at 77K. The heat leakage from 60K to 10K of the bulk is estimated at 79.1mW and the bending strength of the Bi (2223) bulk current leads are 14-23MPa. The strength of the bulk are double or treble according to the Stycast coating on the bulk surface. Due to these superior properties, the Bi (2223) bulk current lead has been successfully used in a cryocooler magnet. The magnet system is running for 26, 000 hours without any degradation of the current lead.