He added, “Even though these tools are developed for national security purposes, they could have applications to varied fields, including next-generation battery manufacturing, fuels for advanced nuclear reactor design and environmental science revealing the transport and fate of microplastics.”
Why had no one put these two pieces of equipment together before? “The ICP-MS needs a positive charge to make our measurement,” Ticknor said. “Uranium, plutonium, most metals, a lot of the periodic table, are happy to be positive ions. Part of the reason that we need to do this simultaneous technique is because elements like fluorine are not amenable to the ICP-MS that we do for uranium. It has to do with the electronegativity of fluorine. With ICP, the goal is to form positive ions to inject into the mass spectrometer. Fluorine very, very strongly wants to have a negative charge.”
Manard explained further, “That’s why we needed to do the LIBS for the fluorine piece of this and then the mass spectrometry for the uranium isotopic determination. Many people have done LIBS and ICP-MS separately, but no one had done both in a multicollector-based fashion.”
Manard conceptualized experiments for a multidisciplinary team at ORNL’s Ultra-trace Forensic Science Center, which in part supports the IAEA. The center’s advanced characterization of nuclear materials provides a better understanding of novel fuel cycle processes.
Ticknor, Cole Hexel and Paula Cable-Dunlap, all of ORNL, served as advisors to the project. Andrews performed LIBS experiments. Daniel Dunlap and Alex Zirakparvar, both of ORNL, readied the ICP-MS instrument to make high-precision isotope ratio measurements. ORNL’s Tyler Spano prepared samples and benchmarked them using Raman spectroscopy, a traditional method to measure chemical composition that can take weeks. Veronica Bradley, a former ORNL postdoctoral fellow, helped set up maps for laser ablation. C. Derrick Quarles Jr. of Elemental Scientific Inc, which manufactures the LIBS system, helped set up methods and tune equipment.
Manard and Ticknor envision applications for their technique beyond nuclear nonproliferation. In fact, when ORNL bought the LIBS instrument to target challenging elements such as fluorine, the research gained teeth — literally. Manard led experiments with researchers at Savannah State University, the University of Maine and ORNL using the new equipment to map fluorine distribution in shark teeth obtained from the Georgia Aquarium. The enamel of shark teeth is rich in fluorine and revealed environmental conditions, both current and prehistoric.
This Oak Ridge National Laboratory news article "Simultaneous detection of uranium isotopes, fluorine advances nuclear nonproliferation monitoring" was originally found on https://www.ornl.gov/news
