SYSTEM AND METHOD FOR THE QUANTITATIVE ANALYSIS OF THE ELEMENTARY COMPOSITION OF MATTER BY LASER-INDUCED PLASMA SPECTROSCOPY (LIBS)

摘要

The present invention relates to a system and a method for measuring the concentrations of the material from a sample (1) comprising a plurality of elements by analysis libs. The material is heated so as to generate a plasma (12) and to determine its chemical composition of the spectral analysis of its radiation. The spectral lines of interest are identified (20) from among those emitted by the constituents of each element constituting the sample (1). The intensities of the spectral lines identified (21) are measured. Starting from an estimation (22,23,24) of the temperature (t), the electron density (n) and of the relative values of the elementary concentrations (c), the chemical composition of the plasma is calculated (27). According to the invention, the absorption coefficient as a function of the wave length is calculated (28) for the spectral lines of interest. Starting from an estimation of the width (l) of the plasma, the spectral luminance of the plasma is calculated (29) for the same spectral zones and is then carried out a comparison (30) of the intensity and the shape of the spectrum thus calculated with those of the measured spectrum. These calculations (27,28,29) and the comparison (30) are repeated in an iterative manner in order to adjust the temperature, the electron density, the relative values of the elementary concentrations and the width of the plasma. The iteration is repeated until the (31) of a difference between the intensity and the shape of the spectrum calculated and those of the measured spectrum which is less than or equal in absolute value than a predetermined threshold value.