Dual-Field Multicollector LG-SIMS Analysis of Mixed U-Pu Reference Particles

Published

June 6, 2025

Author(s)

Evan Groopman, Todd Williamson, Kyle Samperton, Spencer M. Scott, Bryan Foley, Michael Bronikowski, George King, Matthew Wellons

Abstract

In this study, we demonstrate a new dual-field multicollector protocol for magnetic sector large-geometry secondary ion mass spectrometry that enables concurrent analysis of U and Pu isotopes. We apply this analysis protocol to recently produced mixed U-Pu microparticle reference materials, called UPu-100A. These particles, loaded on a Si substrate, show highly reproducible U and Pu isotopic and U/Pu assay results, with particle-to-particle molar variability typically less than 1 % relative, and down to 0.1 % for 235/238U and less than 0.3 % for 240Pu/239Pu. We demonstrate the impact of surface and primary beam sputter chemistry on the acquisition and interpretation of mixed-actinide particle analyses. We show that, in general, consuming most of each particle within a single analysis yields the most reproducible results. Using O3- primary ions reduces sputter chemistry artifacts during particle depth profiling on Si relative to O- primary ions, which enhances reproducibility. The Pu/U relative sensitivity factors for O3- and O- primary ions on Si were 2.036 ± 0.016 (1 SD) and 2.142 ± 0.034 (1 SD), respectively. This work highlights how integration of novel analytical protocols and fit-for-purpose reference materials can push the boundaries of particle-scale material characterization.

Citation

Journal of Analytical Atomic Spectrometry

Pub Type

Journals

Download Paper

https://doi.org/10.1039/D5JA00115C

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Keywords

SIMS, uranium, plutonium, particles, nuclear safeguards, reference materials

Citation

Groopman, E. , Williamson, T. , Samperton, K. , Scott, S. , Foley, B. , Bronikowski, M. , King, G. and Wellons, M. (2025), Dual-Field Multicollector LG-SIMS Analysis of Mixed U-Pu Reference Particles, Journal of Analytical Atomic Spectrometry, [online], https://doi.org/10.1039/D5JA00115C, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=959737 (Accessed October 14, 2025)