Predicting radiation damage in beryllium

Displacement damage in beryllium was predicted as a function of temperature and energy using molecular dynamics simulations. A key aim of this study was to determine if average results from large displacement cascades correspond to values predicted by the Kinchin–Pease (K–P) model. The number of residual defects remaining after 1 ps increased linearly with primary knock-on atom (PKA) energy from 0.5 keV to 2.5 keV, while the extent of residual damage was largely temperature independent from 300 K to 1100 K. The same simulation model was used to predict the directionally averaged probability of displacement as a function of displacement energy, P(EPKA), and thereby the threshold displacement energy at which the probability for displacement is 100%, Ed1.0=105 eV. There is an excellent correspondence between the K–P prediction using Ed=Ed1.0 and the number of residual defects remaining after the initial recovery phase. Also, by utilising P(EPKA), a modification to the K–P model is proposed that gives rise to an average model prediction when EPKA<2Ed1.0.