An experimental approach to the determination of the surface ionization phi(0) in electron probe microanalysis

A compilation of exptl. detd. surface ionization values for Al Ka and Pd La radiation on a wide variety of substrates, ranging from beryllium to bismuth, and measured between 4 and 30 kV, is presented. The values were extd. from the previously reported thin-film measurements on aluminum and palladium films by electron probe microanal. The j(0) values were detd. by establishing the ratios of the intensities emitted from the supported and unsupported films for six film thicknesses and extrapolating towards a film thickness approaching zero. Some 180 j(0) data each for Al Ka and Pd La x-radiation were collected in this way. The purpose of this work was to provide systematic data on which the numerous existing expressions for j(0) could be tested. In the final assessment procedure, in which the authors also included 108 data from the literature, the authors compared the performances of the various expressions from the literature for j(0) and a newly developed expression of the own. The final conclusion is that there is little to be chosen between the three to four of the highest ranking expressions. [on SciFinder (R)]