Development of superconducting magnets using Bi-2212/Ag tapes

Several pancake type superconducting coils were fabricated using Bi-2212/Ag tapes prepared by the combination of continuous dip-coating process and melt-solidification and tested in various temperatures and bias fields. A small Bi-2212/Ag double stacked pancake coil(13 mm/spl phi/ (inner bore)/46.5 mm/spl phi/ (outer diameter)) was used as an insert magnet of a conventional superconducting magnet system. In the bias field of 20.9 T, the generated field of the Bi-2212/Ag coil was of the Bi-2212/Ag coil was 0.9 T, at the I/sub c/ of 310A (criterion 10/sup -13/ /spl Omega/m), in the saturated superfluid helium temperature (/spl sim/1.8 K). Thus, this superconducting magnet system achieved generation of magnetic field of 21.8 T in the full superconducting state. A larger Bi-2212/Ag double stacked pancake type magnet (20 mm/spl phi/ (inner bore)/spl times/94 mm/spl phi/ (outer)) was also fabricated. The generated fields of the magnet at 4.2 K in 0 and 20 T bias fields were 2.6 T (I/sub c/=385A(10/sup -13/ /spl Omega/m)) and 1.08 T (I/sub c/=160 A(2/spl times/10/sup /spl times/13/ /spl Omega/m)), respectively. At about 20 K, in helium gas, the generated field of the magnet was 1.53 T (I/sub c/=225A(10/sup -13/ /spl Omega/m)). >