Enabling orders of magnitude sensitivity improvement for quantification of Ga in a Ce matrix with a compact Echelle spectrometer

Abstract

Chemical analysis of lanthanide materials via laser-induced breakdown spectroscopy (LIBS) is often hindered by the complex spectral response and self-absorption phenomena that occur in the LIBS plasma. Previous attempts to quantify the alloying metal gallium in cerium matrices with a handheld LIBS analyzer were plagued by the inability to resolve major Ga atomic emissions and self-absorption effects, diminishing the fidelity of calibration curves. However, implementing a compact, high resolution Echelle spectrometer coupled with a Stark-broadening based self-absorption correction can enable proper recording of the main Ga I emission at 417.2 nm and improve the sensitivity of calibration curves by two orders of magnitude compared to the handheld device. We demonstrate this by using the mathematical correction on recorded high-resolution spectra from Ce–Ga samples to achieve calibration curves with detection limits as low as 0.008 wt% Ga. This study indicates that using a compact spectrometer capable of higher resolution measurements can yield higher fidelity solutions for Pu chemical analysis via LIBS in constrained environments, e.g., in a glovebox – enabling higher sensitivity in rapid detection of minor elements.