Strain dependence of critical current in internal tin process Nb/sub 3/Sn strands

The development of a high performance superconducting magnet requires a thorough understanding of the strain effect in the critical current density (J/sub c/) of Nb/sub 3/Sn strands. A modified version of the WASP device is used for the investigation of the strain effect. The spring is made of BeCu alloy and is capable of applying strain up to 0.7% reversibly at 4.2 K. Several types of high performance Nb/sub 3/Sn strands (J/sub c/>1000 A/mm/sup 2/ at 12 T and 4.2 K) have been developed using internal tin process. A comparative study on the axial strain dependence of the critical current is performed.