Nuclear Safeguards is a process by which States’ nuclear activities are verified to conform to their international commitments. One aspect of Nuclear Safeguards is the collection and analysis of environmental samples from nuclear sites. Collective and individual particulate material from environmental samples can be characterized to infer details of nuclear activities. Individual microparticles are atom-limited by nature, presenting challenges for their isolation and analysis. Mass spectrometry techniques, such as Secondary Ion Mass Spectrometry (SIMS) and Thermal Ionization Mass Spectrometry (TIMS), are currently used by the International Nuclear Safeguards community to interrogate the elemental and isotopic compositions of actinide-bearing particles. At NIST, we use large-geometry SIMS instruments to develop new particle analysis methods, improve analytical accuracy and reproducibility, and collaboratively develop new microparticle reference materials to enhance the quality and capability of Safeguards-related particle analyses.

• Szakal C., Simons D. S., Fassett J. D. and Fahey A. J. (2019) "Advances in age-dating of individual uranium particles by large geometry secondary ion mass spectrometry". Analyst 144, 4219-4232.
• Groopman E. E., Williamson T. L. and Simons D. S. (2022) "Improved Uranium Particle Analysis by SIMS using O3- Primary Ions". JAAS 37, 2089-2102.
• Williamson T. L., Groopman E. E. and Simons D. S. (2023) "Dual Chronometer Measurements of Uranium Particles by LG-SIMS". Proceedings of the INMM & ESARDA Joint Annual Meeting, Vienna, Austria