Multifilamentary niobium tin magnet conductors

Practical magnet conductors of multifilamentary Nb
3
Sn have been produced in a collaborative programme between A.E.R.E. Harwell and Rutherford Laboratory. The evaluation of these bronze route conductors is described. Conductors studied range from a 1369 filament all-bronze matrix conductor to 5143 and
\sim42,000
filament conductors, containing internal high purity copper protected by diffusion barriers. Filament sizes vary from
\sim 3 - 8 \mu
m diameter. The effect of heat treatment conditions on critical current and transition temperature is presented and it is shown that overall critical current densities greater than those available in niobium titanium can now be produced in multifilamentary Nb
3
Sn magnet conductor.