Correction of self-absorption effect in calibration-free laser-induced breakdown spectroscopy(CF-LIBS) by considering plasma temperature and electron density

Abstract

The self-absorption effect due to optical thickness characteristics greatly affects the measured spectral intensity, which in turn affects the accuracy of CF-LIBS quantitative analysis. In this paper, the emission spectra of laser induced 303 stainless steel plasma are obtained, a new self-absorption correction method that takes into account plasma temperature and electron density is proposed. In order to eliminate the influence of the self-absorption effect, the spectral line intensity is first corrected using an internal reference line that neglects the self-absorption effect, and then the line broadening is determined by calculating the electron density, and spectral line intensity is corrected for the second time. The results show that after calibration, the accuracy of Mn, Cr, Ni and Fe by CF-LIBS is improved 15.4 %, 14.2 %, 2.9 % and 0.7 % respectively, which are much superior to those without self-absorption correction. This method can improve the accuracy of CF-LIBS and facilitate the quantitative analysis of alloy samples. It can be applied to fields such as metallurgy and material composition determination.