Composite conductors containing many filaments of Nb3Sn

A 342 filament Nb3Sn conductor made by "the bronze" approach is described in some detail. Larger conductors containing 1045 and 3553 filaments, respectively, are also mentioned. One of these contains a barrier layer to separate the bronze matrix from high conductivity copper which is required for stability in some applications. A high aspect ratio version of the 3553 filament conductor has also been made. A 67 507 filament conductor carrying 1000 A at 12 T, developed for Lawrence Livermore Laboratories, is shown. It has been made into several different configurations, one with the size and aspect ratio of the 3553 filament conductor shows less anisotropy in current properties with different field orientations.