A computer-assisted method for determining an element fraction of a determination element of an examination region of a sample bombarded with primary electrons, comprising the steps of:
- capturing a backscattered electron signal using a backscattered electron detector,
- obtaining using an X-ray spectroscopy detector a spectroscopy element composition of the examination region,
- combining a measured gray value SM determined from the backscattered electron signal with element fractions of the spectroscopy element composition in order to determine a fraction of the determination element,
- calculating a reference gray value SV using the element fractions of the spectroscopy element composition, and
- determining the fraction of the determination element using a comparison of the measured gray value SM and reference gray value SV.