Robert Johnson University of Virginia Dr. Robert Johnson, University of Virginia, will continue a study of the effects of ion bombardment and ultraviolet radiation on low temperature solid surfaces. Sputtering of ices is a process that has proved to be important in determining the reflectance of the icy satellites of planets in the Solar System. There now exist a large body of laboratory data on the sputtering of ices. This data set has some inconsistencies and large gaps in the materials, incident particles, and particle energies studied. Dr. Johnson will calculate complete data sets for those ices that are critical to the understanding of the surfaces of outer Solar System objects. He will also calculate how these data can be applied to icy satellite regoliths that have grain sizes and porosities much different from those in laboratory studies. The data will be used on the production of molecular oxygen and hydrogen to quantitatively test the various solid-state chemistry models that have been proposed for the production and desorption of new volatiles during irradiation of ice.
