| 摘要 |
PURPOSE:To cool a current lead and a piping for cooling a superconducting coil body, to prevent the temperature rise of a refrigerant due to the intrusion of heat from the outside while cooling even a precooling piping brought into contact with the superconducting coil and to shorten the cooling time in initial cooling by branching the refrigerant from an external refrigerant storage tank and supplying both a refrigerant storage tank and the piping being brought into contact with the superconducting coil body and precooling the superconducting coil with the refrigerant. CONSTITUTION:Since the prolonged time is required by pressure loss, etc. in a coil for initial cooling from a normal temperature, a valve 26 to a refrigerant storage tank is closed up to approximately 20K, a valve 25 for precooling is opened and a coil conductor is cooled from the outside, supercritical helium in the superconducting coil is easy to be flowed, and and cooling is advanced. When the temperature of the coil is brought to a superconductive state, excitation is conducted through conduction from an exciting power supply 15. The temperature rise of a current lead during excitation is inhibited by liquid helium in a storage tank 20 and gas helium. The flow rate of, helium gas flowing in the superconducting coil conductor can be made larger than the case when there is no piping brought into contact with a conventional superconducting coil by approximately 20 times, and the cooling time up to the superconductive state can be shortened to approximately 10%. |
