Energy dependence of the Kα satellite intensity from high-energy electron-impact ionization

The relative x-ray yields corresponding to KL and K ionized atoms have been measured for elements ranging from V(Z=23) to Ni>(Z=28) at incident electron energies of 20 keV and 2 MeV. The intensity ratios of Kα satellite to diagram lines at 2 MeV are found to be lower by a factor ∼ 0.6 than those measured at 20 keV. These results cannot be understood solely in terms of electron shakeoff. It is suggested that the observed energy dependence is due to a competing multiple Coulomb-ionization mechanism.