CURRENT LEAD FOR SUPERCONDUCTING MAGNET DEVICE

PURPOSE:To increase a liquid nitrogen cooling area without increasing in size current leads, a liquid nitrogen vessel and to decrease heat to be invaded to a low temperature side lead by providing a heat exchanging block to be cooled with the liquid nitrogen between a high temperature side lead and the low temperature side lead, and providing a cooling passage of nitrogen gas in the high temperature side lead. CONSTITUTION:A low temperature side lead 12 of an oxide series superconducting conductor is conductively connected to an intermediate connector 24B of a lower surface side of a heat exchanging block 22, and a high temperature side lead 13 formed of conductive metal is conductively connected to an intermediate connector 24A of the upper surface side. Further, a lower end of an outer tube 25 for demarcating a cooling passage 27 to the lead 13 is hermetically coupled, and nitrogen gas l6G of a low temperature evaporated by the block 22 is discharged externally from a discharge port 25A through the passage 27. The lead 13 has a cooling fin 26 spirally protruding from the passage 27, and the block 22 is so formed as to hold a cooling surface area of 50cm or more per rated current 1kA of the current lead.