Applied Spectra reports a major breakthrough in LIBS instrumentation for isotopic analysis of Uranium

April 21, 2024

The new spectrometer/detector innovation led to a detection limit of 1.3 pg of U in LIBS measurement and the potential for accurate analysis of different enrichment grades of Uranium.  This work has been highlighted in Journal at Spectrochimica Acta, Part B, titled “Isotopic analysis of uranium at the picogram level with single shot laser induced breakdown spectroscopy”.

Uranium was measured by laser induced breakdown spectroscopy (LIBS) with a limit of detection of 1.3 picograms with spectral-peak height as the analytical parameter, which shows an improvement of several orders of magnitude compared to other reports in the literature. The improvement is a result of optimizing the choice of the U analytical line, the system hardware, and the light collection and detection efficiency. The research established properties of U line emission (intensity, signal-to-background ratio, isotopic splitting, and spectral interferences) to select an optimum wavelength for analysis. The sample was mock particles from dried, monodispersed U solution droplets (~65 pL in volume) deposited on a Si wafer. LIBS emission spectra from several 235U-enriched samples were measured to demonstrate the performance for isotopic analysis. For isotopic measurements, two masses for total U, 100 pg and 325 pg, were studied. The 235U : 238U isotopic ratio was obtained by peak fitting the LIBS spectra without requiring calibration with the use of enriched standards. Depending on the total U mass and the 235U enrichment, typical relative standard deviations of the isotopic analysis ranged from several percent down to about 1%. Further, the developed method and the reported analytical performance were all based on single-shot LIBS. Overall, the study highlights the potential of LIBS as a robust and sensitive technique for isotopic analysis of U-containing particles.

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