“…Although many features of the radiation damage have been explained, several phenomena are still discussed, including the mechanisms of production of large clusters of defects and dislocation loops, 5,[8][9][10][11][12] the effect of PKA mass on the defect yield, 8,12 the influence of surfaces in the experiments with thin foils, 8 the mobility of self-interstitial atoms (SIAs), clusters (SIACs), and dislocation loops. 2,4,[13][14][15][16] One of the most plausible explanations of the formation of superlattices of bubbles [1][2][3]13,14,16 in several metals under the radiation damage is based on the anisotropic diffusion of SIAs or SIACs. However, there are contradicting statements in the previous works about the mechanisms and dimensionality of di-interstitial SIA (di-SIA) and SIAC diffusion.…”