Investigation of matrix effects on the neutral fractions ejected from ion-bombarded, uranium-containing solids using resonance ionization mass spectrometry

Resonance ionization mass spectrometry (RIMS) has been used to investigate the effect of the sample matrix on the yields of U, UO, and UO2 neutrals desorbed from ion-bombarded, uranium-containing solids. The yield of corresponding secondary ions was also examined by secondary ion mass spectrometry (SIMS). Samples studied were uranium metal, UO2 (polycrystalline and single crystal), and U3O8. The overall efficiency of detection, U+ photoions counted/U atoms sputtered, was approximately 9 x 10-4. Results indicate that the density of ground-state U atoms sputtered from such samples is quite sensitive to oxygen content and surface contamination. The relative ratio of ground-state U atoms sputtered from U metal and UO2 (U0 metal/U0 oxide) with Ar+ was estimated as 4.4 X 101. This relatively large matrix effect severely limits the applicability of SA/RIMS to quantitative analysis of uranium samples