Lawrence Livermore National Laboratory and Lawrence Berkeley National Laboratory scientists used the Advanced Light Source, shown here, to develop a new technique in nuclear forensics. (Photo: Thor Swift/Berkeley Lab)
New research from the Lawrence Livermore National Laboratory (LLNL) has resulted in the development of a novel synchrotron-based scanning transmission X-ray microscopy (STXM) based method which can identify the chemical states and impurities of individual particles, providing a new technique in the field of nuclear forensics.
"STXM allows us to see details in nuclear materials that traditional methods simply could not detect," said lead author and LLNL scientist Rachel Lim. "This ability to pinpoint chemical states and impurities of individual particles marks a major advance for nuclear forensics capabilities."
Described in the Journal of Nuclear Materials, the method utilizes an x-ray beam, focused down to tens of nanometers wide, to scan across uranium samples. As the X-rays pass through the sample detectors measure how many are absorbed at each point for multiple X-ray energies. Thanks to the characteristics of the beam generated by the Advanced Light Source, the team can achieve excellent resolution in their analysis.
"Because each element has its own unique absorption profile—like a fingerprint—STXM can create detailed images and identify the specific elements and their chemical states in very small regions of the sample," added Lim.
Using the STXM method, the researchers can perform non-destructive analysis for trace amounts of nuclear materials quickly and safely.
"The chemical state and impurity profile of a material act as forensic signatures linking it to its origin, processing and environmental exposure, but meaningful interpretation requires high-quality reference data," said Lim. "As more reference data becomes available, this approach could become a standard tool for tracing the history and origins of nuclear materials, making it easier to monitor and protect them."