Superconducting Materials for Particle Accelerator Magnets

Critical current densities of Nb-Ti, Nb-Ti-Ta and Nb3Sn conductors have shown significant recent increases. High Jc is available both from Nb 46.5 wt% Ti and Nb 50 wt% Ti. Recent conductors made at Baoji have particularly high Jc at 5 T, 4.2 K, although not optimized for 10 T, 1.8 K use. Present values of Jc 10 T, 1.8 K in Nb-Ti exceed 1600 A/mm2 (10-14 ¿m) and values of 1900 A/mm2 appear feasible. The higher Hc2 alloys of Nb-Ti-Ta appear capable of 10 T, 1.8 K Jc values of 2500 A/mm2.