Bi-2223超電導材料を用いたバルク電流リードの開発

―冷凍機による伝導冷却超電導マグネットへの適用―

抄録

Bi-2223 bulk current lead has been developed by the sintering technique. The critical current (I_c) and the critical current density (J_c) of the Bi-2223 current lead indicate 1000 A and 1000 A/cm² at 77 K in a self-magnetic field, respectively. The magnetic field dependence of the I_c values for the developed current lead was measured at several temperatures. The J_c value of more than 600 A/cm², which corresponds to the I_c value of 600 A, was shown in 5 K, 1.2 T and 50K, 0.6 T. The heat leakage of 183 mW was calculated for a pair of the current leads at temperatures from 50 K to 5 K. The cantilever bending strength of 29-47 MPa was obtained for the Bi-2223 bulk leads. The developed Bi-2223 lead was applied to the cryocooler-cooled superconducting magnet. The Bi-2223 current lead is a key component for the magnet system. About 160 of the current leads have been already applied to the magnets, indicating high reliability.