Kinetic and diffusion stages of helium penetration in metals from low temperature gas-discharge He-H plasma

The specific way of helium penetration (and other inert gases) under their irradiation by low-energy ions in glowing discharge plasma is discussed. The analysis of the experimental profile of helium distribution in irradiated aluminium has shown a deep helium penetration due to radiation induced diffusion. That is why while considering the deep penetration phenomenon the two basic stages are taken into account. The first stage is a kinetic one, when implantation of He+ ions into the near-surface metal layers occurs. Then during ion retardation their radiation induced diffusion begins, i.e. the second stage. The expressions satisfactorily describing the experimental results and evolution of helium distribution at both stages are proposed. A possible mechanism of radiation induced diffusion is discussed. 24 refs.; 1 fig