A Nb3Sn high field dipole [for SSC]

A dipole magnet approximately 1-m long with an 8-cm bore has been fabricated from cable made from Nb₃Sn multifilamentary strands. The coil consists of four layers of conductor wound in pairs to eliminate internal joints. Each set of layers is separately constrained with Kevlar-epoxy bands, and the complete assembly is clamped in a split laminated iron yoke. The inner coil pairs were wound before heat treating, whereas the outer coils were formed for prereacted cable using conventional insulation. A NbTi version of the magnet was fabricated using Superconducting Super Collider (SSC) conductor to test the construction techniques. This magnet reached a maximum central field of 7.6 T, at 4.4 K, which is very close to the limit estimated from conductor measurements. The Nb₃Sn magnet, however, only reached a maximum field at 8.1 T, which is considerably short of the field expected from measurements on the inner cable