부산대학교 도서관

If$ Nb_3 Sn$is the best superconductor candidate for the realization of high field magnets (for 10–11 Tesla), its implementation remains delicate because of the great brittleness of material after the heat treatment necessary for the formation of$ Nb_3 Sn$compounds. The conventional insulation for$ Nb_3 Sn$Wind & React coils requires performing, after the heat treatment, a vacuum resin impregnation, which adds to the cost and raises failure risk. We have proposed a one-step innovating ceramic insulation deposited directly on the un-reacted cable. After the heat treatment, we obtain a coil having a mechanical cohesion, while maintaining a proper conductor positioning and a suitable electric insulation. We have shown that using this insulation in a coil manufacturing process does not affect the electrical properties of the$ Nb_3 Sn$wires. A solenoid of small dimensions (9$ast$20 turns on an internal diameter of 22 mm) has produced a magnetic field of 3.8 T at 740 A. It was tested with success in high external magnetic fields: the quench limits have been imposed by the strand and the insulation was not damaged.