Attenuation of Low-Energy Electrons by Solids: Results from X-Ray Photoelectron Spectroscopy

The scattering half-thickness for electrons has been experimentally determined to be ≈ 0.25 μg/${\mathrm{cm}}^2$ (≈ 13 Å carbon) for 1169-eV electrons and ≈ 0.21 μg/${\mathrm{cm}}^2$ (≈ 10 Å carbon) for 920-eV electrons. The corresponding mass-scattering coefficients are 2.75 ± 0.19 and 3.32±0.37 ${\mathrm{cm}}^2$/μg. Other useful and related attenuation parameters are defined and calculated. These results were obtained from measurements of the attenuation by thin carbon films (5-60 Å) of monoenergetic photoelectrons originating from gold substrates irradiated with Mg $K_{\alpha }$ x rays, and also from measurements of the concomitant increase in carbon photoelectron intensity. Scattering of electrons in the energy range about 1 keV is greater than has generally been indicated.