<title>Spectroscopic analysis of signals on LIBS experiences: fit of experimental measurements</title>

In the LIBS experiences (Laser induced breakdown spectroscopy), the created plasma is far inhomogeneous and the observed lines present a high absorption. This fact gives rise to drawbacks in the performance of the technique to calibrate the content of any element in the sample. Both the most studied and easier approach to modeling such absorbed plasmas is the homogeneous model, where we consider the same temperature and density in the whole plasma plume. In this work, in order to quantify the results obtained in alloy and soil samples, we searched experimental conditions where the plasma was almost homogeneous. The minimum-squares fit method was carried out to analyze the measured lines on the homogeneous plasma framework. Two lines of the same element and ionization state were employed such a way the homogeneous zone was fully characterized and plasma parameters such as temperature, density and the generic shape of the optical thickness were determined. With these parameters we were able to quantify the percentage of any element in the sample with an uncertainty of 1%.