Vacancy and interstitial loops in irradiated copper

Significant advances have been made in diffuse scattering studies of irradiation induced dislocation loops in metals. Numerical calculational procedures have been developed that provide accurate diffuse scattering cross sections for vacancy and interstitial loops, and these cross sections have been used in conjunction with x-ray diffuse scattering studies of neutron and ion irradiated copper. Size distributions and concentrations have been 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 the smaller sizes. (author)