RESPONSE FUNCTIONS FOR THE QUANTITATIVE-EVALUATION OF COMPROMISE CONDITIONS FOR MULTI-ELEMENT ANALYSES WITH ENERGY-DISPERSIVE X-RAY-FLUORESCENCE SPECTROMETRY

Figures‐of‐merit are developed for simultaneous multi‐element analysis with energy‐dispersive X‐ray fluorescence spectrometry. Those derived from information theory frequently give optima in regions of poor excitation of one or more elements and have to be restricted to the region above the absorption edge of the highest Z element; the shapes of the surface described by these and other functions are studied and their optima are compared. A product sum function of inverse Poisson standard deviation gives results that best meet the expectations of X‐ray spectroscopists. The location of optima in the space of excitation conditions is dependent upon concentration, but the optimum of the one sample of a batch with the highest overall count rate is still a good compromise between the best experimental conditions and maximum input. These results are substantiated with plots giving the dependence of the figures‐of‐merit from experimental conditions and with spectra at the optima as defined by the different functions. These equations are potentially useful as objective functions in optimization alogorithms as well as for the comparison between the performance of different X‐ray systems. Copyright © 1979 Heyden & Son Ltd.