The Use of a Scanning X-ray Microprobe for Simultaneous XRF/XRD Studies of Fly-Ash Particles

With the opening of the first real `third-generation' synchrotron source in Grenoble, in fall 1994, X-ray sources of unprecedented brilliances and qualities became available to the scientific community. Different X-ray analytical techniques could now be applied on a level that was unimaginable only a decade ago. Here are some preliminary results from an experiment where different analytical techniques have been applied on a micrometer level carried out at the most powerful synchrotron microbeam currently available in the world, the microfocus beamline (BL1) at ESRF. This beamline can now provide micrometer-sized X-ray beams with a flux density up to 10¹⁰ photons μm⁻² at an energy of 13 keV and with a bandwidth of 10^–4. In this experiment, X-ray diffraction and X-ray fluorescence have been combined in order to obtain a precise and comprehensive micro-analytical description of micrometer-sized fly ash particles. These types of particles are heavily inhomogeneous with a very irregular shape that makes them inaccessible to conventional micro-analysis. The experiment was performed in a scanning mode and two-dimensional images of different analytical information were reconstructed from the data recorded during the scan. The major features and limitations of this micro-analytical technique will be outlined and different examples on how the analytical information can be used for generating two-dimensional images of the sample will be demonstrated and discussed.