Nb3Sn superconducting cables processed by internal tin diffusion

Modified fabrication techniques of the internal tin diffusion process and optimization of the reaction condition are discussed. By this process, the large-scale production of practical multifilamentary Nb3Sn conductors has been able to be performed very easily and reliably. The critical current density without stabilizing Cu was achieved 460 A/mm2at 12 T, 4.2 K. Furthermore, the properties of the conductor fabricated from high tin composite are investigated. It was found that there is possibility to fabricate the conductor which has higher critical current density at high fields from high tin composite.