Magnet coil tests with multiple soldered niobium-tin filament conductors

Flat conductors with Nb3Sn/Nb filaments, prepared by the solid state diffusion process were investigated for degradation after bending and tensile loading. Proportionality was found between the critical bending diameter and the distance of the filaments from the neutral zone. Four conductors with rectangular cross-section were stabilized by soldering in parallel to copper foil; coils were then wound and tested in the magnetic field of a niobium-titanium magnet. Measurement of the quench currents confirmed that the conductors were not damaged by the manipulations required. The 5% decrease in current-carrying capacity compared with short sample measurements is ascribed to the more unfavourable cooling conditions in the coil. Individual conductors with a larger number of filaments now available for further tests are reported. (author)