Evaluation of Atmospheric Release Techniques for Atomic Uranium and Thorium

Because certain simple uranium and thorium oxides exhibit ionization potentials which are lower than their metal-oxygen bond strengths their low temperature and pressure chemistry can result in the production of stable ionized species. Release of uranium or thorium vapor in the presence of ambient atomic and molecular oxygen in the upper atmosphere may result in the formation of stable ionic metal clouds which extend over large volumes. Radar and optical observation of these clouds could yield information about upper atmospheric properties. This report reviews a number of techniques for the release of U and Th which may be adaptable to field experimental conditions. The techniques reviewed include the release of volatile compounds containing U and Th, evaporation by chemical and electrical heating, and exploding wires.