Pancake coils made from Bi-2223/Ag tapes

摘要

Small double pancake coils with a 15 mm bore were fabricated from Ag sheathed multifilamentary Bi-2223 tapes by the 'wind and react' technique. The electric insulation between the turns consists of an alumina screen print paste. In a double pancake coil with a total tape length of 73 m, a magnetic field of 1.34 T was generated at liquid helium temperature. The technique for the fabrication of the test coils was optimized in order to achieve the critical current density of the tapes in the coils. The critical current in different sections of the coils was controlled by electric field vs. current measurements. Correlations between the filament structure of the tapes and critical bending diameter of the tapes in the coil are discussed. (C) 1998 Elsevier Science Ltd. All rights reserved. [References: 9]