ИСТИНА

The wellknown approach for calibration-free (CF) LIBS are used Boltzmann plot, which require optically thin plasma under local thermodynamic equilibrium. Strict fulfilling of these requirements is barely possible and preliminary check for them is hardened under extreme conditions like open space or deep sea. We can calculate a spectrum for stationary laserinduced plasma with a particular elemental composition. Afterwards, we used multiparametric optimization to fit experimental and model spectra, in which relative elemental concentrations served as variables. For relative simplicity of an implementation, a gradient-free method has been chosen to minimize the loss function.