QUANTITATIVE AES-VII - THE IONIZATION CROSS-SECTION IN AES

Inner shell ionization cross-sections are analyzed for use with Auger electron spectroscopy (AES). Correlations of the cross-sections of Gry zinski, Casnati et al., Jakoby et al, and Drawin are made with experim ental data from the digital Auger database. Jakoby et al.'s cross-sect ion is realistic for It shell ionizations but can become negative for other shells unless modified, so is of limited use for AES. Results fo r the ratios of experimental and calculated intensities for electron b eam energies of 5 keV and 10 keV, for overpotentials in the range 2-60 , are used to rank the effectiveness of the remaining three cross-sect ions. The experimental ratios show means and scatter standard deviatio ns of 1.01 +/- 0.12, 0.99 +/- 0.05 and 1.04 +/- 0.09 when compared wit h the predictions for the cross-sections of Gryzinski, Casnati et al. and Drawin, respectively. Casnati ed al.'s cross-section provides the best correlation, with the goodness of fit being similar for ionizatio ns in the K, L, M and N shells. Casnati ef al.'s cross-section is ther efore recommended for future use in AES. The use of Gryzinski's or of Drawin's cross-sections, by comparison, can lead to errors as high as 50% at the low value of 1.5 for the overpotential (i.e. for high-energ y Auger electrons). (C) Crown copyright 1998. Reproduced with the perm ission of the Controller of Her Majesty's Stationery Office.