An energy loss function for keV electrons from Au has been derived from reflected electron energy loss spectrometry spectra using a Landau formula modified to account for elastic scattering. The influence of the latter was analyzed using Monte Carlo analysis, The energy loss function was verified by using it for background subtraction of the Au 4f x-ray photoelectron spectroscopy spectrum according to Tougaard’s method. This approach led to a more reasonable source function, characterized by two satellite peaks. Herman-Skillman atomic orbital calculation, based on the Xa approximation, suggests these might correspond to shake-up peaks associated with the Au 6s-->7s transition.