Groups of displacement cascades calculated independently with different simulation models and computer codes were compared on a statistical basis. The parameters used for this comparison were the number of Frenkel pairs produced, the percentages of vacancies and self-interstitial atoms in clusters, the spatial extent and the aspect ratio of the vacancies and the self-interstitial atoms formed in each cascade. One group of cascades was generated in the binary collision approximation and all others by full molecular dynamics. The latter results differed primarily due to the empirical interatomic potentials used and, to some extent, in code strategies. Cascades were generated in simulation boxes at different initial equilibrium temperatures. Only modest differences in the predicted numbers of Frenkel pairs were observed, but the other cascade parameters could differ by more than 100%. The consequences of these differences on long-term cluster growth in a radiation environment were examined by means of object kinetic Monte Carlo simulations. These were repeated with 3 different parameterizations of self-interstitial atom and self-interstitial atom-cluster mobility. The differences encompassed low to high mobility, 1- and 3-dimensional migration of clusters, and complete immobility of large clusters. The object kinetic Monte Carlo evolution was followed until 0.1dpa was attained. With the range of object kinetic Monte Carlo parameters used, cluster populations after 0.1dpa differed by orders of magnitude. Using the groups of cascades from different sources induced no difference larger than a factor of 2 in the object kinetic Monte Carlo results. No correlation could be found between the cascade parameters considered and the number densities of vacancies and self-interstitial atoms predicted by object kinetic Monte Carlo to cluster in the long term. However, use of random point defect distributions instead of those obtained for displacement cascades as input for the object kinetic Monte Carlo modeling led to significantly different results. It was therefore suggested that although the displacement cascade characteristics considered did not correlate with cluster populations in the long term, other aspects of the internal structure of cascades do.

Dependence of Radiation Damage Accumulation in Iron on Underlying Models of Displacement Cascades and Subsequent Defect Migration. A.Souidi, C.S.Becquart, C.Domain, D.Terentyev, L.Malerba, A.F.Calder, D.J.Bacon, R.E.Stoller, Y.N.Osetsky, M.Hou: Journal of Nuclear Materials, 2006, 355[1-3], 89-103