| 摘要 |
PURPOSE:To prevent malfunction and thermal conduction by constituting a power lead by a material, electric resistance thereof is slightly high, while interposing a cooling fin between the power lead and a permanent current switch. CONSTITUTION:A thermal type permanent current switch 7 is connected to superconducting coil 1 and a power lead 8 in an inner tank 2. The lead 8 is constituted by a material of electric resistance high to some extent such as copper of comparatively low purity, for example, phosphorus deoxidized copper, so as to inhibit most of a thermal intrusion from the outside, cooled and held by an outer cylinder 9, and connected to an external power supply by an external terminal 10. Then end section of the lead 8 is connected to cooling fins in a connecting section between the lead 8 and the switch 7, and the lead 8 and the switch 7 are connected through the cooling fins. Accordingly, heat generation on excitation or demagnetization by the high resistance of the lead 8 is not transmitted over the switch 7. |
