The perspective of new multi-layer reference materials for confocal 3D micro X-ray fluorescence spectroscopy

Multi-layered components are commonly used in hi-tech branches of modern industry. This fact generates a need for suitable reference materials for experimental examination of such specimens, and it also induces the development of mathematical procedures for quantification. To reveal experimentally the chemical composition of (multi-)layered specimens in 3D space in a non-destructive way, a confocal 3D micro X-ray fluorescence spectroscopy (3D μXRF) can be employed. The scope of this paper covers preparation, preliminary experimental examination and quantification of new, multi-layer stack systems as the perspective of reference materials to be used in 3D μXRF spectroscopy. The prepared stacks consist of nine individual layers based on a low-Z organic matrix loaded alternately with Cu₂O and ZnO oxides. The stacks are characterized by the homogeneous areal distribution of inorganic fillers and the constant thickness of distinguishable layers to the extent of millimeters. A Monte Carlo (MC) simulation was used to reconstruct the chemical composition, mass density and thickness of individual layers within the stacks. Results of the simulation accurately reflected the nominal mass shares of fillers and the thickness of layers additionally determined by optical microscopy and 2D μXRF scanning. The prepared stack systems seem to be suitable materials for the validation of mathematical procedures for the quantification of multi-layer specimens examined by depth-sensitive X-ray techniques. Copyright © 2012 John Wiley & Sons, Ltd.