Experimental determination of the surface ionisation in electron probe microanalysis

An exptl. procedure is described for measuring the surface ionization values j(o) using thin-film measurements on a wide variety of substrates. The j(o) values are detd. by establishing the ratios of the film element x-ray intensities emitted from supported and unsupported thin films for a no. of different film thicknesses and extrapolating towards a film thickness approaching zero. A no. of 180 j(o) data each for Al Ka and Pd La X-radiations between 4 and 30 kV, on substrates ranging from beryllium up to bismuth, were collected in this way. The purpose of this work was to provide a systematic database on which a variety of existing expressions for j(o) could be tested. In the final assessment procedure, in which the authors also included 108 data from literature, the authors compared the performance of the various expressions from literature for j(o), as well as a newly developed one of the own. The final conclusion is that there is little to be chosen between the three highest-ranking expressions. [on SciFinder (R)