High-fluence he-implantation in Ni trapping, re-emission, and surface modification

Abstract

Simultaneous measurements have been made of blister formation and gas re-emission during bombardment of Ni with 8–40 keV ³He⁺ at room temperature. It is shown that re-emission and blister formation start at the same critical fluence. An initial peak in the re-emission rate is correlated to a step in the total number of blisters. A more detailed analysis of the experimental data shows that the area contributing to gas re-emission is much larger than the blister area. This suggests the formation of an interconnected layer below the surface in which cracks at blister sites provide gas emission channels to the surface.