Optimization of laser-induced breakdown spectroscopy for Be element detection with self-absorption effect correction

Abstract

The laser-induced breakdown spectroscopy detection of the Be element can provide on-site rapid detection technology in the field of geological exploration. The self-absorption effect of Be results in weaker detection accuracy in the medium to high content range. This study calculated the self-absorption parameters for the self-absorption effect of the Be element, and optimized the detection delay and laser energy with the goal of reducing the self-absorption effect. The influence of laser energy on the self-absorption effect with two different light collection angles was discussed through plasma imaging and spatially resolved spectroscopy. The variation in self-absorption with increasing energy is interpreted as the result of competition between two factors: the increase in plasma temperature and the increase in optical path length due to plasma volume expansion. The opposite trends observed in axial and radial spectroscopy are attributable to the different expansions of the plasma height and width. With optimized parameters, the calibration model was corrected for self-absorption effects, resulting in a linear detection range of 6 to 10 000 ppm, which broadens the range of on-site detection of Be containing minerals by LIBS.