Differential inelastic electron scattering cross sections from experimental reflection electron-energy-loss spectra: Application to background removal in electron spectroscopy

The possibility of extracting absolute inelastic electron scattering cross sections K(T) (differential in energy loss T and path length) for solids from experimental electron spectra is studied. Assuming homogeneous scattering properties for the solid, a formula is found, which allows a direct determination of [λL/(λ+L)]K(T) from a measured reflected electron-energy-loss spectrum (REELS) resulting from a monoenergetic beam of electrons incident on the surface of the solid. Here λ is the inelastic electron mean free path and L≃2${\lambda }_1$ where ${\lambda }_1$ is the transport mean free path for elastic electron scattering. The formula is applied to experimental REELS spectra of aluminum. The resulting cross sections are discussed in relation to a theoretical calculation based on dielectric-response theory. The determined cross sections are applied to remove the inelastic background signal from Mg–Kα(hν≃1254 eV) and synchrotron-radiation-excited (hν≃250 eV) photoelectron spectra of aluminum. The resulting primary excitation spectra are discussed in relation to the results of existing procedures.