Ionization cross-sections for the L23-edges of the elements Sr to Mo for quantitative EELS analysis

Quantitative microanalysis by electron energy-loss spectrometry requires knowledge of partial inner-shell ionization cross-sections. Data for the L23-edges of the elements strontium to molybdenum are not well known. We have therefore measured cross-section ratios (k-factors) for the L23-edges of the elements Sr to Mo using thin film oxide-standards. The experimental values are compared with calculations derived from a modified hydrogenic and a Hartree-Slater model. The results are presented in terms of an integrated dipole oscillator strength to facilitate both comparisons between theory and experiment, and calculations of cross-sections for particular experimental conditions. While hydrogenic theory oscillatorstrength values deviate from the experimental ones by more than 30%, there is good agreement between Hartree-Slater theory and experiment. We have also compared the relative microanalytical sensitivities for the M45- and L23-ionization edges of these elements.