NEUTRON AND X-RAY SCATTERING STUDIES OF NEUTRON IRRADIATED IRON CRYSTALS. J. L. Robertson and R. E. Stoller. Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA

Results on the structure of defect cascades produced by fast neutron irradiation of Fe single crystals will be presented. Diffuse neutron and x-ray scattering methods are used to study correlations of the interstitial Fe atoms introduced by the irradiation. Because the irradiation is done at ~300K there is significant recombination of defects (interstitials with vacancies). Consequently, the defect concentration is quite low, less than 1 ppm, however, the response of the lattice to the presence of the defects (displacement field) is quite large. The interpretation of the scattering data benefits significantly from the results of recent efforts to construct computer models of the defect cascades. These models follow the time evolution of the defect cascades and show that the surviving interstitials aggregate while the vacancies do not appear to be mobile. Interpretation of these results with regard to radiation hardening in pure metals will be discussed.