Defect production and recovery in fcc metals irradiated at 4.2 K

Four fcc metals, Al, Cu, Ni, and Pt, have been irradiated at 4.2 K at the Livermore Rotating Target Neutron Source (RTNS-II) to fluences of 1 to 2 x 1021 n/m2. The sample resistivities were monitored during the irradiation. Following irradiation, the sample resistivities were monitored after isochronal anneals to 320 K. The initial resistivity damage rates for all four metals could be predicted to within +-10% from the results of irradiations in a pure fission spectrum by damage energy scaling. The results of isochronal annealing studies in Al and Cu were nearly identical to recovery curves obtained after fission spectra irradiations to comparable damage levels. On the other hand, both Ni and Pt exhibited less recovery than that observed after fission spectra irradiations, due primarily to less recovery in Stage 1