Localization of defects in multifilamentary Nb3Sn conductors by an inductive procedure

A procedure is described to measure continuously and without damage the local dependence of the critical current of multifilamentary Nb3Sn conductors of any length. In the superconducting state the conductor is moved continuously through an area with flux density B produced for example by a split coil. The magnetic field of the induced screening currents measured outside the conductor by Hall probes is a measure of the critical current of the conductor. The procedure applied to multifilamentary Nb3Sn conductors allows to localize areas of the conductors with critical current degradation of more than about 10 %. The conductors can be tested before being wound into coils.