Trapping and release of rare gases by 304L stainless steel

Helium andargon ions in the energy range 100 to 1400 eV and at doses varying from 1012 to 1015 ions/cm2 were implanted in a 304L stainless steel sample. Following implantation a linear temperature increase of the sample caused the gases to be released. The thermal release rates were studied as a function of ion dose and energy. The maxima observed in the thermal release rates are used to determine activation energies for thermally activated processes occurring in the metal. A rapid increase in the CO release rate coincident with the highest temperature He re-emission maximum indicates that the same mechanism is responsible for the release of both CO and He. It is suggested that the transport mechanisms revealed here are important in controlling void formations in neutron irradiated metals.