Quantitative analyses of glass via laser-induced breakdown spectroscopy in argon

• Published in: Spectrochimica acta. Part B: Atomic spectroscopy 2014-11, Vol.101, p.32-45
• Main Authors: Gerhard, C., Hermann, J., Mercadier, L., Loewenthal, L., Axente, E., Luculescu, C.R., Sarnet, T., Sentis, M., Viöl, W.
• Format: Article
• Language: English
• Subjects: Algorithms; Breakdown; Calibration-free LIBS; Computation; Engineering Sciences; Glass; Glass analysis; Laser-induced breakdown spectroscopy; Local thermodynamic equilibrium; Measurement methods; Optical glass; Optics; Photonic; Radiance; Spectra; Spectroscopy; X-rays
• ISSN: 0584-8547; 1873-3565
• DOI: 10.1016/j.sab.2014.07.014

We demonstrate that elemental analysis of glass with a measurement precision of about 10% can be performed via calibration-free laser-induced breakdown spectroscopy. Therefore, plasma emission spectra recorded during ultraviolet laser ablation of different glasses are compared to the spectral radiance computed for a plasma in local thermodynamic equilibrium. Using an iterative calculation algorithm, we deduce the relative elemental fractions and the plasma properties from the best agreement between measured and computed spectra. The measurement method is validated in two ways. First, the LIBS measurements are performed on fused silica composed of more than 99.9% of SiO2. Second, the oxygen fractions measured for heavy flint and barite crown glasses are compared to the values expected from the glass composing oxides. The measured compositions are furthermore compared with those obtained by X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy. It is shown that accurate LIBS analyses require spectra recording with short enough delays between laser pulse and detector gate, when the electron density is larger than 1017cm−3. The results show that laser-induced breakdown spectroscopy based on accurate plasma modeling is suitable for elemental analysis of complex materials such as glasses, with an analytical performance comparable or even better than that obtained with standard techniques. •Plasma modeling including the calculation of the plasma pressure•Calibration-free LIBS based on accurate modeling of the plasma emission spectrum•Quantitative LIBS analysis of multicomponent optical glasses including oxygen•Good measurement accuracy obtained only for small delays between laser pulse and detector gate