Intermediate Joint of Current Lead in Conduction-Cooled Superconducting Magnet System

The semi-retractable current lead is composed of a normal metal element, conducting the current from room temperature to intermediate temperature, and a high-temperature superconducting element, conducting the current down to liquid helium temperature. The normal metal element is disengaged from the high-temperature superconducting element through the multicontact connector without disturbance to the insulating vacuum space and without requiring complete removal of the normal metal element. The current lead is applied into the conduction-cooled superconducting magnet system developed by ourselves. The intermediate joint with a lockable set point is thermally connected to the first-stage of a cryocooler and carries current through a strip of louvered material. The performance of current lead is investigated with respect to the electrical contact resistance during the magnet charging process. The effects of current level and operating temperature on the heat generation in the intermediate joint are also discussed.