The probing depth of total electron yield in the sub-keV range: TEY-XAS and X-PEEM

X-ray absorption spectra can be collected in multiple ways, each exhibiting a different probing depth. The total electron yield signal contains contributions from primary, Auger and secondary electrons. We present data on the total electron yield probing depth at core level energies ranging from 77 to 929 eV. By coating materials with chromium overlayers, we find that the maximum probing depth increases with core level energy from 15 to 141 إ. We demonstrate that the Auger electron contribution to total electron yield intensity is negligible, therefore X-ray absorption spectra acquired in X-ray PhotoElectron Emission spectroMicroscopy (X-PEEM) are equivalent to spectra acquired by total electron yield. We find that the signal intensity decreases exponentially with coating thickness, and that total electron yield probing depth and Auger electron range (calculated in the continuously slowing down approximation) are similar at low energies, but diverge for kinetic energies above 400 eV.