Effect of self-interstitial cluster migration on helium diffusion in iron

The influence of self-interstitial cluster migration on defect evolution in irradiated α-Fe is studied using an object kinetic Monte Carlo model with input from ab initio and molecular dynamics calculations. Helium implantation and desorption is simulated during isothermal annealing under different conditions of temperature and sample thickness. Results are compared with experimental measurements existing in the literature. In particular, the effect of self-interstitial cluster migration on the fraction of He released during annealing is studied. The results of these calculations point towards a strong effect of traps in the nucleation and growth of He-vacancy clusters.