Fabrication and transport properties of Bi-2212/Ag multifilamentary coils for high magnetic field generation (II); high field performance test

摘要

A compact superconducting magnet with 30 mm inner bore has been fabricated in a wind and react process by using Bi-2212/Ag multifilamentary tapes. The magnet is composed of 3 double pancake coils of 88 mm in outer diameter. As for a reinforcement against large magneto-electrjc force, the combination of Ag-Mg alloy tape co-winding and epoxy impregnation is employed. High field performance of this magnet is examined in backup fields up to 20 T at 4.2 K. Critical current density at 20 T is 516 Amm~(-2) (generating field: 1.10 T) and 112 Amm~(-2) (0.95 T) with the criteria of 1 x 10~(-13) Ωm for oxide part and whole cross section of the conductor, respectively. The results indicate that the reinforcement is effective against the hoop stress of 120 MPa.