Speaker
Description
X-ray fluorescence (XRF) spectroscopy is a well-established and versatile analytical tool for determining elemental composition. However, conventional XRF techniques provide only depth-averaged information, which limits their suitability for stratified samples where depth-resolved spectral data are crucial.
Confocal micro-XRF analysis overcomes this limitation by employing a geometric configuration that restricts the detector field of view, enabling non-destructive, three-dimensional elemental mapping with micrometre-scale spatial resolution. Traditionally, polycapillary focusing optics are used in both the excitation and detection paths to define a small probe volume, with depth profiling achieved through mechanical translation of the sample along the axis perpendicular to its surface.
In this contribution, an alternative approach to depth resolved XRF analysis is presented. It combines the principles of confocal geometry with the full-field capabilities of a pnCCD based Color X ray Camera, eliminating the need for sample translation. The excitation beam is focused, and the sample is tilted with respect to the beam axis. A parallel 1:1 X‑ray optics is positioned perpendicular to the primary beam to ensure proper imaging conditions for the pixel detector. With this arrangement, fluorescence from different depth layers appears at distinct locations on the detector plane. Consequently, the depth information is encoded directly as lateral shifts within the recorded image.
The results obtained demonstrate that the experimental setup provides reliable depth discrimination within layered structures. The presented approach is a promising alternative to conventional confocal micro‑XRF, offering a simplified mechanical design while retaining a depth-dependent response. Its applicability is tested on model samples representing painting stratigraphy, composed of thin pigment layers deposited over ground materials. This confirms that the method is well suited for the non‑destructive examination of stratified structures, particularly when physical sampling is undesirable or impossible.