CURRENT LEAD OF SUPERCONDUCTING DEVICE

摘要

PURPOSE:To reduce heat intruding into a current lead by a method wherein the amount of gas of vaporization of liquid helium gas and the amount of circulating gas of helium gas are controlled in such a way that the amount of the circulating gas of the helium gas into the current lead is controlled at the amount of circulating gas exceeding the amount of current conduction time gas, which is decided by a self-cooling condition at the time when a rated current is made to flow through the current lead. CONSTITUTION:A control circuit 23 of a control means 21 monitors a temperature change in a lead 4 on the side of a high temperature through a temperature sensor 12 to output a control signal 13A for the amount of circulating gas and a control signal 23B for the amount of gas of vaporization of liquid helium gas. A heat power supply 25 controls a current in a heating unit 24 arranged in the liquid helium gas on the basis of the signal 23B. In the case heat (p) intruding into a vacuum heat-insulating vessel is little and a desired amount Q of the circulating gas is not obtained, a control condition is set so that the unit 24 vaporizes the liquid helium gas to supply the amount of the shortage. Thereby, a current lead 3 is forcedly cooled and heat of intrusion into the lead 3 can be reduced.