Change in Critical Surface of Nb3Sn Wire by Neutron Irradiation*)

Neutron irradiation on Nb3Sn wire changes its superconducting properties. It is well known that the critical current increases by the irradiation once and then decreases by further irradiation. In this paper, the effective upper critical magnetic field and the critical temperature of the irradiated Nb3Sn wire were investigated, and the mechanism that causes such changes were discussed qualitatively by focusing on the role of the irradiation defects together with the normal metallurgical flaws. In addition, a critical surface was taken up and the general tendency of the change in the surface was discussed. & COPY; 2023 The Japan Society of Plasma Science and Nuclear Fusion Research