Isotopic Quantification and Analysis of Uranium Oxide for Environmental Sampling and Nuclear Safeguards Applications using Laser-Induced Breakdown Spectroscopy (LIBS)

Laser-Induced Breakdown Spectroscopy (LIBS) has previously been used to determine the isotopic composition of samples of uranium and plutonium at reduced pressure and in a background gas of helium, respectively. Recently, LIBS was used to determine the isotopic composition of samples of enriched uranium in a glass matrix under room temperature conditions and atmospheric pressure in air. For environmental analysis applications, samples are currently collected, packaged, and shipped to an approved analytical chemistry laboratory. This practice can take days to weeks to complete and is also costly. In this paper, we will present our work on the analysis of isotopic enriched samples of uranium oxide powders using a carbon adhesive tape as the substrate. We report the preliminary results of the analysis of isotopic samples of uranium enriched in 235U between 1 and 97 percent using a high resolution spectrograph with a resolving power of 75,000. Using this procedure, the total mass adhered to the tape is approximately 5–9 milligrams. Since our laser spot size on the sample is approximately 200 to 300 microns in diameter, the total mass of the sample analyzed is on the order of 1 microgram or less per enrichment. This type of analysis procedure is much closer to environmental analysis required in a field setting. The field analyst simply needs to take a carbon tape and press it against the sample and analyze the material collected using an appropriate LIBS instrument. The analysis can typically be completed in minutes compared to the current methodologies that can take days and in some cases weeks