QUANTITATIVE-ANALYSIS OF INDIVIDUAL PARTICLES BY X-RAY MICROFLUORESCENCE SPECTROMETRY

A fundamental parameters method using polychromatic x-ray microbeam ex citation was developed and applied to the quantitative analysis of ind ividual particles from 50-160 mu m, From the ratio of the projected ar ea of a particle to the cross-sectional area of the microbeam, an effe ctive portion of the microbeam irradiating the particle can be determi ned and used to correct the measured x-ray intensities, Because partic les in this size range may not be infinitely thick and may contain unm easurable elements such as C and O, calculation of the average mass th ickness of the particle allows complete matrix absorption corrections to be made, For this purpose, the ratio of coherent to incoherent x-ra y tube target lines scattered from the particle was used to calculate the average atomic number of the particle, and its mass thickness was determined from incoherent scatter, A parametric equation was derived and tested. In addition, irregularly shaped particles were analyzed us ing a well known equation usually applied to flat samples having inter mediate thickness, Both models were tested with homogeneous glass part icles of known composition and size.