Development of high field superconducting magnet by using multifilamentary compound tape

A superconducting pancake coil was wound from a newly-developed multifilamentary V3Ga tape and its coil characteristics was investigated by comparing with that of a conventional surface-diffusion Nb3Sn tape. The V3Ga tape are 0.16 mm in thickness and 5 mm in width, including about 2,500 V3Ga filaments and a copper stabilizer. The coil consists of 6 double pancake modules of 30 mm in bore diameter. The coil was tested in a Nb-Ti magnet having a bore diameter of 124 mm. It was able to produce a magnetic field of 12 Tesla at a coil current of 142 A without any training, while a Nb3Sn coil of similer dimensions exhibited several premature quenches. The other characteristics on sweep rate dependences upon quench currents, flux jump phenomena, hystereses and remanent fields, were also investigated. It has been confirmed that multifilamentary tape has a superior performance to surface-diffusion tape.