Defects and transmutations in reactor-irradiated copper

From measurements made at 4.2 K, the residual resisitivity increases produced by reactor irradiation near room temperature were studied in pure Cu up to fluences of 4.2 x 1023 n/m2 > 1 MeV and 12 x 1023 thermal n/m2 by methods which resolved the effects due to transmutations and to defects. While the increase in resistivity due to transmutations is linear, that due to defects falls off rapidly with increasing fluence. The defect damage rates at low doses depend upon initial sample conditions that are related to impurities, but they become equal above approx. 6 x 1021 n/m2 (E > 1 MeV). Computations of defect concentrations using these resistivity data and earlier x-ray results, which measure dislocation loops, can be brought into reasonable agreement if the specific resistivity attributed to a single defect is decreased when that defect becomes part of a dislocation loop