THERMAL-PROPERTIES OF IMPREGNATING MATERIALS FOR STABLE SUPERCONDUCTING MAGNETS

The minimum quench energies (MQEs) of superconducting (SC) wires have been measured precisely by means of a 'Carbon Paste Heater'. The therm al behavior just before the normal generation of the heavy loaded SC w ire was observed to determine the quenching We learned that once a nor mal region is produced, it should spread rapidly regardless of the sur rounding conditions The MQE, however, would increase when a local temp erature rise before quenching is prevented by using certain materials around the SC wire. For example, high thermal diffusivity in impregnat ing materials or low thermal conductivity in wire insulation will be n eeded when disturbances occur outside of the SC wires In the previous paper, we showed the effects of enamel insulation for improving stabil ity. Thus, in this study, we examine the relation between MQE and the thermal properties of the impregnating material Several kinds of impre gnating materials were selected and the thermal properties are compare d with enlarging MQE in mind. We have searched for an impregnating mat erial that has the thermal property required for improved stability.