A standardless X-ray diffraction method for the quantitative analysis of multiphase mixtures. II. Application to non-infinitely thick samples

In 1987, Rius, Plana & Palanques [J. Appl. Cryst. (1987), 20, 457-460] devised an X-ray powder diffraction method based on the `least-squares' determination of calibration constants using only the diffracted intensities and the calculated absorption coefficients of the components. This method was developed for `infinitely thick' samples, a condition which is seldom met by airborne particulates because of the small amount of material normally available. Since the analysis of such samples may become one of the principal applications of the method, this condition represents a serious limitation. The simplest way to overcome this limitation is by correcting the measured intensities. This can be done either by direct measurement of the sample transmission, or alternatively, by using refined transmission values. In the latter case no experimental values are necessary. With the help of some test calculations, the viability of both possibilities has been explored.