Investigation of Fast-Neutron Radiation Damage in Nearly Perfect Copper Crystals by X-Ray Diffraction Techniques

Abstract

The effects of fast-neutron irradiation at about 40°C in nearly perfect copper crystals have been examined by x-ray diffraction techniques. Anomalous x-ray transmission (Borrmann) and Bragg reflection geometries were used to investigate the changes in diffracted intensities caused by defects produced by the neutron irradiation. Both Borrmann and Bragg peak intensities were reduced to values significantly below those for perfect crystals, and the reduction in the Bragg intensities was accompanied by a large increase in the diffuse scattering in the wings of the peak. It is shown that isolated point defects and the distortion associated with them would not account for the changes in x-ray intensities. Annealing studies indicated that both vacancies and interstitials were present in these crystals after irradiation, and all of the damage was removed by annealing at 500°C.