A Gaussian spot overlap ablation model for prediction of aluminium alloy spectral peak intensity in high pulse repetition frequency LIBS

Abstract

The use of microjoule high pulse repetition frequency (PRF) lasers as excitation sources is an important direction in the miniaturisation of laser-induced breakdown spectroscopy (LIBS) instruments. However, high PRF LIBS is sensitive to experimental parameters, and the relationship between the experimental parameters and the spectral intensity of high PRF LIBS is less studied. In this work, we present a model based on Gaussian spot overlapping ablation with aluminium alloys as samples. After the index values have been collected in the non-motion state, the model derivation formula can be used to calculate the intensity of the spectral peaks under any proposed experimental parameters in the motion state. The experimental results show that the mean relative error (MRE) between the measured and predicted values of spectral peak intensity is ≤0.15 under different experimental parameters, and this result proves the validity of the model in predicting the spectral peak intensity. Meanwhile, we used 5 standard aluminium alloy samples to construct the standard curves of measured and predicted values under different experimental parameters. The experimental results show that the MRE between the measured and predicted values is ≤0.15, and the two standard curves fitted with the measured and predicted values have a high similarity with an average R² ≥ 0.85. This study is expected to provide a universally applicable and efficient method for the quantitative analysis of high PRF LIBS in different application scenarios.