Powder-in-tube (PIT) Nb3Sn conductors for high-field magnets

New Nb3Sn conductors, based on the powder-in-tube (PIT) process, have been developed for application in accelerator magnets and high-field solenoids. For application in accelerator magnets, SMI has developed a binary 504 fila ment PIT conductor by optimizing the manufacturing process and adjustment o f the conductor lay-out. It uniquely combines a non-copper current density of 2680 A/mm(2)@10 T with an effective filament diameter of about 20 mu m. This binary conductor may be used in a 10 T, wide bore model separator dipo le magnet for the LHC, which is being developed by a collaboration of the U niversity of Twente and CERN, A ternary (Nb/7.5wt%Ta)(3)Sn conductor contai ning 37 filaments is particularly suited for application in extremely high- field superconducting solenoids. This wire features a copper content of 43 %, a non-copper current density of 217 A/mm(2) @ 20 T and a B-c2 of 25.6 T. The main issues and the experimental results of the development program of PIT Nb3Sn conductors are presented and discussed in this paper.