Vacancy and interstitial loops in irradiated copper

Diffuse scattering of irradiation induced dislocation loops in metals are studied. Numerical calculational procedures were developed that provide accurate diffuse scattering cross sections for vacancy and interstitial loops, and these cross sections were used in conjunction with X-ray diffuse scattering studies of neutron and ion irradiated copper. Size distributions and concentrations were obtained for both vacancy and interstitial loops and these results are compared with electron microscopy measurements. The size distributions obtained from diffuse scattering measurements show the vacancy loops to be smaller and more numerous than the interstitial loops, and indicate that equal numbers of vacancies and interstitials are in loops. The diffuse scattering and microscopy size distributions agree at the larger sizes, but the diffuse scattering method identifies more loops of smaller sizes.