Large-scale molecular dynamics simulations of collision cascades caused by primary knock-on atoms in Fe

Abstract

We report on large-scale molecular dynamics (MD) simulations of energetic primary knock-on atoms (PKA) in crystal BCC Fe. We carry out 1000 randomly directed PKA collision cascades simulations at PKA energies of 0.1, 0.5, 1, 2, 3, 4 and 5 keV using the large-scale atomic molecular massively parallel simulator code. We study the statistical spread of the number of displaced atoms and recombination within a collision cascade in Fe. It is shown that the PKA must be launched in around a few hundred different randomly chosen directions for the variance in the number of displaced atoms to reach a steady value. We also compare our results for the number of displaced atoms with that from the Norgett, Robinson and Torrens model and other MD simulations of collision cascades.