| 摘要 |
PURPOSE:To increase thermal conductivity and improve start time and cooling efficiency without decreasing the' mechanical strength of a bobbin and a bobbin cover, by forming the bobbin and the bobbin cover of silver alloy having mechanical strength and thermal conductivity which are larger than or equal to the respective specific values. CONSTITUTION:Ag-Mg-Ni alloy subjected to oxidation heat treatment at 800-900 deg.C is used as the material of a bobbin 11 and a bobbin cover 12. A coil 2 is formed by winding a superconducting wire of Nb3Sn or the like in a coil type around the bobbin. The bobbin cover 12 is arranged on the outer periphery, and fixed to the upper part of a two-step stage 7 of a vacuum vessel 5. A GM refrigeration machine 10 is operated, and the coil 2 is cooled by the cold head 4. The superconducting state of the coil 2 can be obtained in about 20 hours after the cooling is started, and the amount of consumption power can be restrained to be about 1/5. The equivalent effect can be obtained with a bobbin and a bobbin cover using one alloy out of Ag-Ni, Ag-Ti and Ag-Cu. |
