Laser-induced breakdown self-reversal isotopic spectrometry for isotopic analysis of lithium

Abstract

Online monitoring or in-situ isotopic analysis techniques in extreme environments are strategic tools in nuclear industry. A new optical method for performing isotopic analysis in solid samples at ambient pressure has been developed: Laser-Induced Breakdown self-Reversal Isotopic Spectrometry (LIBRIS). This method uses self-absorption of atomic or ionic resonance lines that are emitted from a non-uniform laser-induced plasma. It takes advantage of the fact that the spectral width of the absorption dip is much smaller than the spectral width of the emission line profile. Isotopic measurements were carried out on lithium samples by measuring the spectral position of the absorption dip that is shown to have a linear dependence on the 6 Li isotopic abundance. Stand-off and real-time analysis can be performed without any sample preparation or pre-treatment. The effect of the laser wavelength, of the ambient gas and of the gate delay is investigated. Optimum conditions lead to a relative uncertainty of about 6 % on the isotopic abundance measurement of 6 Li. The influence of the spectral shifts due to Stark and Doppler effects on the performance of LIBRIS are discussed.

Progress in calibration-free laser-induced breakdown spectroscopy

“…The low performance was due to the fact that the hypotheses of model validity were generally not all satisfied. Although it is now well accepted that experimental conditions can be easily found to satisfy the hypotheses of congruent ablation [40,41] and LTE [42,43], and that spatial uniformity can be reached in appropriate experimental conditions (see Section 2), the condition of optically thin emission is hardly achieved for dense laser-induced plasmas [36,44,45].…”

Laser Ablation Plasmas and Spectroscopy for Nuclear Applications

“…It was reported that bulk lithium isotopic assay can be determined using LIBS to within a 95% confidence interval in minutes to an hour for enrichment levels ranging from 3% to 85%. Laser-induced breakdown self-reversal isotopic spectrometry (LIBRIS) was developed by Touchet et al 343 that exploits the fact that the spectral width of the absorption dip of self-reversed emission line involving the ground state is much smaller than the width of the overall emission line profile. It was noted by the authors that the Doppler and Stark shift effects were observed to shift the location of the absorption feature in the self-reversed emission line; thus, matrix-matched samples must be used to construct a calibration curve as these effects depend on changes of the plasma conditions that the matrix composition strongly influences.…”

Short-Pulse Lasers: A Versatile Tool in Creating Novel Nano-/Micro-Structures and Compositional Analysis for Healthcare and Wellbeing Challenges

“…However, the intense development of LIBS started much later, when reliable gain-switched pulsed laser sources became available and intensified charge-coupled devices enabled time-gated spectra recording. In the last two decades, innumerable applications have been developed in various domains [176][177][178][179]. Given the immense success of LIBS analysis on Mars [180], the technique was chosen by the American, Chinese and European space agencies for new exploration missions on the red planet starting in 2021 and 2023.…”