Three-Dimensional Chemical Mapping with a Confocal XRF Setup

Abstract

A new approach for the nondestructive reconstruction of stratified systems with constant elemental composition but with varying chemical compounds has been developed. The procedure is based on depth scans with a confocal X-ray fluorescence setup at certain energies near absorption edges. These so-called marker energies, where XAFS signals of the involved chemical compounds differ significantly, can also be used to uncover the chemical composition and its topology. A prominent field of application is homogeneous material that is degraded due to chemical reactions like oxidation or reduction. A procedure for the semiquantitative reconstruction of stratified material by means of depth scans at marker energies is elaborated and validated and a three-dimensional mapping is presented.

mySpot: a versatile microfocussing station for scanning methods at BESSY II

“…To be able to make some assumptions on those unknown elements, the Compton scattering is measured simultaneously. The model is developed by the Work group of B. Kanngießer at the TU Berlin, and works for nite and for layered samples (Kanngießer et al, 2012;Lühl et al, 2013;Mantouvalou et al, 2011). All the capillaries were produced by Institut für Gerätebau Berlin.…”

New developments of X-ray fluorescence imaging techniques in laboratory

“…Of course, it also enables a depth elemental profiling. There are many reports of depth elemental profiling for layered materials such as paint layers [29][30][31][32][33][34][35][36][37][38][39]. The author's research group at OCU has reported a depth elemental profile for car paint chips, which have several layers depending on the type of car and manufacturing process [40].…”

Confocal X-ray technology based on capillary X-ray optics

“…In XAFS, the measurement of the X-ray absorption coefficient of a material as a function of energy can be performed with such methods as a fluorescence mode and a transmission detection. Confocal XAFS is based on the fluorescence mode (Lühl et al 2013).…”

“…A reliable reconstruction algorithm for obtaining undistorted spectra for superficial and in-depth layers was developed to calculate the attenuation coefficients of the analyte for successive layers, which facilitates a new spectroscopic tool for 3D resolved nondestructive chemical speciation (Lühl et al 2012(Lühl et al , 2013.…”