"No EPMA matrix corrections utilize the Z fraction calculations at this time."

Could you please explain me more. My knowledge at this point close to zero and I thought

5 of 10 corrections we can use in PFE use Z-correction (the first correction in **ZAF**).

Could you recommend me something to return to the right way.

This is recent EPMA physics work, there is not a lot of reading I can suggest except for the discussions on this forum.

If you read the abstract I posted you will see that backscatter is not affected by mass. This is supported by empirical data and Monte Carlo modeling.

However, in the analytical physics models in Probe for EPMA (and all other analytical models that I know of), the Z component of the ZAF correction is combined with the absorption correction in phi-rho-z modeling, and because the absorption correction utilizes mass fractions (e.g., mass thickness because they utilize mass absorption coefficients which are normalized to mass!), they incorrectly conflate these calculations with the backscatter correction which should not be mass based. Electron backscatter (and continuum production for that matter) is solely based on electrodynamics. Note that the energy loss terms also utilize mass fractions because they utilize mass thickness.

But a properly physics based approach would not utilize mass fractions because mass has essentially no effect on our EPMA physics. We can see this in more rigorous physics based approaches such as that in Penepma/Penelope Monte Carlo methods, which utilize attenuation coefficients and do not include the implicit mass biases from elements with different A/Z ratios.

You mentioned the example of the difference in Zbar for PbSiO3 when calculated using mass fractions versus Z (Yukawa) fractions. This large difference in Zbar is due to the large difference in the A/Z ratios of Si vs. Pb. The abstract attached in the post above shows some examples of other compounds with large differences in A/Z. Consider that for a compound such as PbS, the differences in average Z for mass versus Yukawa Z fraction are ~20%. Since the backscatter correction contribution to the total matrix correction is approximately 20% in such a material, the relative error we might expect is ~4%, which we can easily observe empirically.

We are currently working on new analytical physics models that will not include these mass biases which should dramatically improve EPMA accuracy in these cases.