PARAMETERS FOR THE RATIO METHOD BY X-RAY-MICROANALYSIS

Atomic or weight ratios of elements can be calculated routinely from X-ray intensities of ultrathin samples without recourse to standards by the “ratio method”, using precalculated proportionality factors. The derivation of the ionization cross section (O), fluorescence yield (ω), line intensity fraction (L) and spectrometer efficiency (T) parameters, needed for the calculation of the proportionality factors, is discussed and suggested “best values” are given. Failure of the ratio method as commonly used to give adequate results with L-or M-lines is attributable to breakdown of the ionization cross-section formula. A simple procedure is given for calculation of line intensity fractions, the results are compared with previous methods. © 1979, American Chemical Society. All rights reserved.