The retention of Ar in low energy high fluence Ar-Irradiated Mo and Si

The retention of argon in low energy (≤ 1 keV) high fluence (≥ 1017 cm−2) argon irradiated Mo and Si has been studied by Thermal Argon Desorption Spectrometry and Transmission Electron Microscopy. It is shown that high fluence argon trapping cannot be described by a linear superposition of low fluence trapping processes. This is partly due to the already known effect of gas-sputtering, but in addition there are important effects due to the development of irradiation-induced substructures. In Mo the creation of self-interstitial loop segments intersecting the surface lead to a significant increase in Ar trapping, while in Si the creation of Ar bubbles via irradiation-induced transport mechanisms is held responsible for extra trapping.