Helium irradiations of copper at 1 to 25 keV: range profiles, reemission, and blistering

A fairly comprehensive (but by no means exhaustive) study of the effects of 1–25 keV helium ion bombardment of copper is presented. The range distributions of 1, 5, 10, 15, 20, and 25 keV ions have been measured with a resolution of 300 A (FWHM) and compared to theory; they are wider than calculated for amorphous copper. Surface topography (blistering), gas reemission, and the helium depth profiles, under high dose bombardment (2.9 × 1017 to 18.7 × 1017 He/cm2), have been studied at 25 keV at room temperature and at 10 keV at 200 and 400 °C. The results are compared to data in other metals and analysed in terms of current models. The gas pressure model of blistering is favored over the stress model. Evidence is found for considerable swelling (60%). Surface roughness keeps increasing with dose after blistering has disappeared and surpasses the blister lid thickness.