A process was considered for creating a flux of self-interstitials by irradiation. This was illustrated by analyzing a case, with coupled rate and diffusion equations, in which a pre-existing concentration of vacancies was swept away by interstitials. It was noted that, for this effect to occur, the interstitial concentration had to remain sufficiently low for clustering not to occur, and the impurity content had to be sufficiently low for interstitial trapping not to occur.

R.A.Johnson: Nuclear Instruments and Methods in Physics Research B, 1995, 102[1-4], 103-6