LIGHT NOBLE GAS DIFFUSION IN GENESIS SAMPLES

Introduction: One of the primary goals of the Genesis mission is to obtain very high precision isotopic measurements of the solar wind. The collector materials were carefully chosen for purity and gas retention properties. However, at high enough temperatures, it is possible for the lighter gases to undergo some diffusion, potentially modifying elemental and isotopic ratios. All possible sources of losses should, therefore, be investigated to improve the precision and coinfidence in the results. Motivation: Previously, Meshik et al [1] did UVlaser and step-wise pyrolysis of He and Ne in aluminum on sapphire (AloS) and polished aluminum samples. The AloS samples were part of the collector arrays, and are pure aluminum deposited on a sapphire substrate. AloS was specifically chosen for its noble gases retention properties. The polished aluminum sample came from what was originally a shield for the battery compartment and is made of a highly-polished 6061 T6 aluminum alloy.