Degradation of transition temperature and critical current density in neutron irradiated Nb3Sn and V3Ga

The effects of neutron irradiation on transition temperature of Nb3Sn wire and V3Ga tape conductors have been investigated. Samples were irradiated in the Japan Material Testing Reactor (JMTR) at = 150°C with the neutron flux (En> 1 MeV) of 1 × 10¹³n.cm^-2.sec^-1. Transition temperature, critical current density and long range order parameter were followed on V3Ga against neutron fluence up to 2.9 × 10¹⁹n.cm^-2. It was found that the irradiation reduces Tcas much as 60% in V3Ga for a fluence of 2.9 × 10¹⁹n.cm^-2. Study on Tcchange together with annealing behavior strongly suggests the necessity of appropriate shielding in its application to fusion magnets.