Uranium Ion Yields from Monodisperse Uranium Oxide Particles.

Secondary ion mass spectrometry (SIMS) plays an important role in nuclear forensics through its ability to identify isotopic ratios of particles accurately and precisely from samples obtained by inspectors [Boulyga et al., J. Anal. At. Spectrom. 30, 1469 (2015)]. As the particle mass can be on the order of subpicograms, it is important to maximize the sample utilization efficiency of U+ to make high-quality isotopic measurements. The influence of primary ion beam species and polarity on U+ sample utilization efficiency has been previously investigated by Ranebo et al. [J. Anal. At. Spectrom. 24, 277 (2009)]. However, the effect of sample substrate on uranium ion production efficiency and sputtering profile has not been investigated. This work will explore those influences on sample utilization efficiency by analyzing monodisperse uranium oxide microspheres deposited onto graphite and silicon planchets. The particles were mapped using an automated scanning electron microscope, and their coordinates were co...