ABSTRACT
Thin copper tubes or wires are generally used for current leads which supply electric current to a superconducting magnet at cryogenic temperatures. However, a large heat leakage of about 1 W/kA appears at RT (room-temperature) atmosphere through a current lead even in a case of optimized gas-cooled lead. The heat leakage occupies a great part of total one in a superconducting magnet system.
