Integral bremsstrahlung energy as an inbuilt standard in energy‐dispersive electron probe microanalysis

To improve the accuracy of the energy‐dispersive electron probe microanalysis (EPMA EDS) without measuring the probe current, it is proposed to normalize the measured analyte net X‐ray intensity to the bremsstrahlung integral energy of the analyzed sample. The integral energy is calculated using a modified Kramers formula, the parameters of which have been refined based on processing the spectra of single‐element samples (4 ≤ Z ≤ 83), acquired in the incident electrons energy range from 10 to 25 keV. The dependence of the bremsstrahlung integral energy on the atomic number of the sample and the incident electrons energy is obtained, and recommendations are given for calculating the mean atomic number of multicomponent samples. It is shown that even with a significant variation (within a factor of 2 or more) of the probe current or the X‐ray gathering solid angle, the use of the proposed normalization method improves the reproducibility of analysis to a value characteristic of measurements at a stable probe current and a standing solid angle. The method is recommended for the development of standardless EPMA EDS.