Energy dependence of the trapping of uranium atoms by aluminum oxide surfaces

We have measured the energy dependence of the trapping probability for sputtered 235U atoms striking an oxidized aluminum collector surface at energies between 1 eV and 184 eV. At the lowest energies approximately 10% of the uranium atoms are not trapped, while above 10 eV essentially all of them stick. In addition, we present trapping probabilities averaged over the sputtered energy distribution for uranium incident on gold and mica.