Test of fiber-reinforced type of Nb3Sn superconducting coils

A superconducting coil using a Nb₃Sn fiber-reinforced type of wire was fabricated and tested. Each superconducting filament of the wire was reinforced by a tantalum fiber. The coil was prepared in a wind-and-react process and was completed by epoxy impregnation. The continuous length of the wire was 250 meters, and 100-meters of it were used for the coil. The quench current in liquid helium reached similar levels to the critical current of the short sample of the wire without degradation. The strain dependence on operating current was described and compared with calculations using two-dimensional analyses. As a reference, another coil using an internally reinforced wire with the similar specifications was prepared and tested.