Effects of Neutron Irradiation on Carbon Doped MgB2 Wire Segments

We have studied the evolution of superconducting and normal state properties of neutron irradiated Mg(B.962C.038)2 wire segments as a function of post exposure annealing time and temperature. The initial fluence fully suppressed superconductivity and resulted in an anisotropic expansion of the unit cell. Superconductivity was restored by post-exposure annealing. The upper critical field, Hc2(T=0), approximately scales with Tc starting with an undamaged Tc near 37 K and Hc2(T=0) near 32 T. Up to an annealing temperature of 400 C the recovery of Tc tends to coincide with a decrease in the normal state resistivity and a systematic recovery of the lattice parameters. Above 400 C a decrease in order along the cdirection coincides with an increase in resistivity, but no apparent change in the evolution of Tc and Hc2. To first order, it appears that carbon doping and neutron damaging effect the superconducting properties of MgB2 independently.