Formulation of a universal electron probe microanalysis correction method

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Abstract
A new correction method for obtaining quantitative electron probe microanalysis results is described. It utilizes data provided by Monte Carlo simulations and tracer measurements to obtain a detailed picture of the way in which the x‐ray emission process is influenced by the relevant experimental parameters. Then empirical equations are derived which model the intensity of x‐ray emission for an extremely wide range of experimental conditions, encompassing electron beam energies from 5 to 40 keV, characteristic x‐ray wavelengths from 11.4 to 0.08 nm, angles of electron incidence from 90° to 40° and elements ranging from beryllium to uranium in the Periodic Table. The method treats separately, as with the traditional approach, the effects of atomic number difference in specimen and standard, x‐ray absorption and x‐ray fluorescence. The correction method was tested on an extensive range of microanalysis data and shown to work well under all conditions, providing chemical compositions which are accutate to within a few percent relative. The capability of handling ultra‐light element (beryllium to sodium) analysis is particularly impressive and the r.m.s. error of 3.8% for carbon analysis on carbides is very close to the errors incurred in measuring actual x‐ray intensities. The correction program is currently being developed for commercial use on IBM‐compatible computers and the final stage in the evolution of the universal correction will be to extend it to deal with the analysis of thin surface films.