Improvement of superconducting properties of Bi-2212 round wire and primary test results of large capacity Rutherford cable

We have developed HTS cables using Bi-2212 round wires, which have high mechanical strength and an average J(c) of 200kA/cm(2) at 4.2K in self-field. Four designs of cables were fabricated in this work and those cables could carry I-c values from 1kA to 10kA at 4.2K and self-field depending on the number of strands. A 70m-long 20-strand Rutherford cable was successfully manufactured. Optimization of heat treatment conditions was effective to reduce I-c degradation observed in the case of heat treatment with a long length. I-c vales of a Rutherford table were measured under loading at 4.2K in 4T, The critical values of the stress on face loading and edge loading were 60MPa and 100MPa, respectively. We successfully obtained high J(c) value of 500kA/cm(2), which was almost double that of the conventional wires capitalize "Rutherford".