X-ray microanalysis of light and stratified samples, possibilities and limitations

Modeling of physical phenomena taking place in microanalysis can show limit ations as well as possibilities of the method. Experimental microanalytical data, particularly k-ratios, have been compared with calculated ones obtai ned by mathematical simulation. The model uses the single scattering Monte Carlo algorithm, where "Bethe cross section" is introduced for the descript ion of inelastic events. Various ionization cross sections have been tested to show their influence on the distribution functions Accuracy of the simu lation has been tested at the boride and carbide datasets, comparing calcul ated k-ratios with experimental data. They have revealed the uncertainty in the mass absorption coefficients and their limitation to the quantitative analysis of very light elements. Layered samples present the most crucial t est for the model. Monte Carlo calculation results are compared with experi mental data and commercial analytical programs. The paper has shown that th e correction program based on first principles gives comparable accuracy wi th analytical approaches for all cases. The progress in the quantitative an alysis is conditioned by the progress in the theory as well as by the progr ess in the accurate experimental determination of some physical parameters.