Defect production in tungsten: A comparison between field-ion microscopy and molecular-dynamics simulations

Molecular dynamics (MD) computer simulations of 20 - 30 keV self-ion bombardment of W were performed and compared to past field-ion microscopy (FIM) studies [M. I. Current et al., Philos. Mag. A 47, 407 (1983)]. The simulations show that the unusually high defect production efficiencies obtained by FIM are a consequence of a surface effect, which greatly enhances defect production compared to that in the crystal interior. Comparison of clustering of vacancies and the formation of interstitial atoms found in the FIM experiments and MD simulations shows overall good agreement.