The genesis solar wind concentrator target : Mass fractionation characterised by neon isotopes

Issue Title: The Composition of Matter The concentrator on Genesis provided samples of increased fluences of solar wind ions for precise determination of the oxygen isotopic composition. The concentration process caused mass fractionation as a function of the radial target position. This fractionation was measured using Ne released by UV laser ablation and compared with modelled Ne data, obtained from ion-trajectory simulations. Measured data show that the concentrator performed as expected and indicate a radially symmetric concentration process. Measured concentration factors are up to 30 at the target centre. The total range of isotopic fractionation along the target radius is 3.8%/amu, with monotonically decreasing ^sup 20^Ne/^sup 22^Ne towards the centre, which differs from model predictions. We discuss potential reasons and propose future attempts to overcome these disagreements. [PUBLICATION ABSTRACT]