Sputtering of uranium

Sputtering yields for uranium metal under bombardment by 13 - 120 keV protons and by 20 - 120 keV He+ are presented. Angular distributions of the material sputtered by these ions are also given. Sputtering yields for 40 and 80 keV Ar+ were measured as well.

The technique employed to make these measurements was the detection of fission tracks in mica produced by ^(235)U sputtered onto collector foils which were subsequently exposed to a high fluence of thermal neutrons. The technique is extremely sensitive and allowed the measurement of sputtering yields less than 10^(-4) atoms per ion. It also made possible a detailed study of the emission of chunks from the uranium targets during sputtering. Mass distributions of chunks emitted during bombardment by 40 - 120 keV protons and by 80 keV argon are presented.

Comparisons are made between the experimental results and those predicted by the Sigmund theory of sputtering.