Effect of matrix temperature on the LIBS signal of Au

In the field of gold exploration, low sensitivity and poor reproducibility are the main problems that hinder the application of LIBS technology. In this paper, an experimental system for lateral collection of spectra with sample temperature control was built, and temperature experiments were carried out on pure gold and artificial specimens with different gold contents to study the influence of the LIBS signal of Au by using the matrix temperature. The experimental results of the pure gold samples demonstrated that increasing the matrix temperature could significantly improve the LIBS signal intensity and signal repeatability. In the artificial specimen experiments, the same enhancement of the LIBS signal quality by increasing the matrix temperature was observed, with a 280% increase in signal intensity, 20% increase in the signal to noise ratio (SNR), and 260% decrease in the limit of detection (LOD) at 973 K. Further theoretical calculations prove that the signal quality is improved by the increase in ablation and electron density through the increase in matrix temperature, while the high temperature environment provides a stable environment for the plasma. Therefore, increasing the matrix temperature can effectively improve the detection limit of Au as well as the signal reproducibility, which is of great significance to the application and development of LIBS in gold exploration. Significant increases in signal intensity, signal quality, ablation and plasma electron density were observed for the gold element as the sample temperature increased, but the plasma temperature decreased.