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 to a method for measuring the elementary concentrations of matter from a sample (1) containing a plurality of elements by LIBS analysis. The matter is heated so as to generate a plasma (12) in order to determine the chemical composition thereof from the spectral analysis of the radiation thereof. Spectral rays of interest are identified (20) among those emitted by the constituents of each element in the composition of the sample (1). The intensities of the identified spectral rays (21) are measured. The chemical composition of the plasma is then calculated (27) based on an estimation of the temperature (T), of the electronic density (ne), and of the relative values of the elementary concentrations (Cx). According to the invention, the absorption coefficient based on the wavelength is calculated (28) for the spectral areas of the rays of interest. Based on an estimation of the plasma width (L), the spectral luminance of the plasma is calculated (29) for the same spectral areas, and a comparison is made (30) between the intensity and the shape of the spectrum thus calculated and those of the measured spectrum. The calculations (27, 28, 29) and the comparison (30) are repeated in an iterative manner in order to adjust the temperature, the electronic density and the relative values of the elementary concentrations and of the plasma width. This iteration is repeated until a difference between the intensity and the shape of the calculated spectrum and those of the measured spectrum which is lower than or equal to a predetermined threshold value in terms of absolute value is obtained (31).