Penetration of oxygen into beryllium irradiated with deuterium and helium ions

The measurements on oxygen retention in beryllium irradiated with deuterium or helium ions and then exposed to air at temperatures of 300 and 645 K are presented and discussed. It is shown that irradiated beryllium accumulates oxygen in the ion stopping zone. After high fluences of D +/He + the interconnected porosity is developed, being responsible both for the D 2/He transport to the surface during implantation and for the penetration of oxygen containing molecules into the bulk of irradiated Be. The amount of Be atoms forming the inner surfaces developed due to the He-ion bombardment is estimated to be about 3 times as large as that after D-ion implantation. The open porosity could be imagined as a network of tunnel-like channels. The experimental data allows to estimate the radius of channels (3–10 nm) and their areal density (10 10–10 11 cm −2).