Relativistic Effects in Au L X-Ray Production by 0.5-3.0-MeV Protons

Intensities and energies of gold Lα, Lβ, and Lγ composite x-ray peaks have been measured with a Si(Li) detector as a function of proton bombarding energies from 0.5-3.0 MeV. The ratios of LαLβ and LαLγ peaks reach a maximum value at Eₚ≈1 MeV. An upward shift in the energy of the Lγ peak of {≈} 100 eV was observed at Eₚ=0.5 MeV. Both effects (shifts and ratios) are due, at least in part, to the energy dependence of the L-subshell hole-production cross sections. The experimental results for the intensity ratios are in better agreement with theory if relativistic L-shell wave functions are used in the plane-wave Born-approximation calculations for L-subshell hole production.