X-ray production cross sections, intensity ratios, and centroid energy shifts of Ag K and L and Au L x rays produced by 16O beams of 12-50 MeV

The 12-50-MeV ¹⁶O beam-induced K and L x rays of Ag and the L x rays of Au from thin targets were studied with a Si(Li) detector. Absolute K and L x-ray production cross sections were derived from measured x-ray yields and compared to available theoretical calculations for inner-shell Coulomb ionization cross sections. Inclusion of Coulomb repulsion, binding, and ${\left(\frac{Z_1}{Z_2}\right)}^3$ effects in the plane-wave Born-approximation calculations gives good agreement with experimental values of ${\sigma }_{KX}$ for Ag. The agreement between theory and experiment for L-shell ionization is not as good, possibly owing to the effects of multiple ionization on the fluorescence yield, although the energy dependence of ${\sigma }_{LX}$ for Au is well reproduced. The energies of the Ag K α and K β and Au L α, L β, and L γ lines were observed to change with beam energy as did the intensity ratios of these lines. HFS calculations for the Ag K α and K β lines indicate that the observed shifts are probably associated with multiple M-, not L-, shell ionization.