| 摘要 |
PURPOSE:To alleviate the amount of heat penetrating into liquid helium under excitation and demagnetization by a method wherein a removable current lead is made as a current lead of gas-cooled system with helium gas. CONSTITUTION:In the case of exciting a superconductive coil 1, the removable current lead 8 is moved downward and coupled with a conduction removable member 9 into the open state of a permanent current swtich 7, and a ferromagnetic field is generated by operating the external power source 10. Thereafter, the ferromagnetic field is kept by short-circuiting the coil 1 by closing the switch 7. Then, the lead 8 is released from coupling with the member 9 by upward movement, and a valve 8b is closed into a state of steady operation. Heat penetration from the lead 8 to the liquid helium 3 is carried out via flexible pipe 11 in the steady state; however, there is a small amount of penetrating heat. |
