Researchers at Los Alamos National Laboratory have, for the first time, used a breakthrough technique with a goal of better identifying the origin of nuclear materials — a tool that could someday help efforts to prevent the spread of nuclear material around the globe.
Using a commercially developed benchtop instrument, called a Laser Ablation Laser Ionization Time-of-Flight Mass Spectrometer (LALI-TOF MS), researchers were able to characterize mock nuclear fuel pellets that incorporate specific elemental and isotopic fingerprints. The first laser “blows off” (ablates) a few molecules of material from the sample’s surface, while the second ionizes the neutral particles to turn them into charged ions, which are then separated by their unique mass.
The LALI-TOF MS instrument used by the Los Alamos researchers enabled the rapid analysis of nuclear materials for most of the elements in the periodic table. “We were able to use the LALI-TOF MS to identify the composition of the mock nuclear fuel sample in under 30 minutes,” said Karla Erickson, a scientist at Los Alamos and lead author on the paper reporting these findings. “It was surprisingly comprehensive. We identified materials in the sample we didn’t even know were there.”
“Sometimes when you’re looking for a certain element, you’re not looking for others, so you can miss things,” said Rebecca Chamberlin, a scientist at Los Alamos and lead on the project. “But with this method, we saw the make-up of the whole sample at once.” This is especially powerful for identifying materials that were intentionally tagged with elemental and isotopic signatures or characterizing those that were not.
Nuclear forensics investigations are used in a variety of scenarios — for example, when nuclear or radioactive materials are discovered outside of regulatory control or if law enforcement seized nuclear materials at a port of entry or border crossing. “Of course, the Laboratory is always preparing for the worst-case scenario — situations that would require fast analysis to determine where the nuclear material came from,” Chamberlin said.
“We need to be able to very quickly and precisely identify the nature of the material. Is it enriched? Is it an oxide?” Erickson added. “Having those answers can steer us toward the next steps of the investigation, to allow us to pinpoint where it came from and how it was made. This new instrument could potentially be a way to do that.”
Erickson and Chamberlin noted that the commercial instrument is easy to deploy in a laboratory environment and potentially can be hardened for field use. Additional research is needed to better understand the extent of the LALI-TOF MS capability before it is proven reliable enough to be transferred to operational nuclear forensics programs; however, there is already excitement about how this instrument could complement existing capabilities and accelerate conclusions and decision making.
Paper: “Analysis of tagged uranium oxide pellets with laser ablation laser ionization TOF-mass spectrometry.” Journal of Radioanalytical and Nuclear Chemistry. DOI: https://doi.org/10.1007/s10967-025-10436-0
Funding: U.S. Department of Energy, National Nuclear Security Administration, Office of Defense Nuclear Nonproliferation R&D
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