A new approach to reach the best resolution of X-ray microanalysis in the variable pressure SEM.

A validation of our recent new approach is presented here in order to better interpret the EDS analysis results in low vacuum SEM. This approach is based on correlation between two concepts: the electron beam skirt radius in the gas characterized by RS and the X-ray emission volume radius in the material characterized by RX. If RS≤RX; then the skirt impact on the analysis is null and the best possible X-ray lateral resolution within the limitations imposed by gas scattering is obtained. In order to follow the relationship between RS and RX, two aluminum foils with different thickness (2 μm and 20 μm) embedded separately in epoxy resin were used. The results showed the existence of the optimal experimental conditions depending on the pressure and the energy that verify the condition of RS≤RX. The experimental and simulated results show the great consistency of this approach.