Confocal Micro X-Ray Fluorescence Analysis (confocal µXRF)

Microscopic X-ray fluorescence analysis (Micro-XRF or µXRF) uses X-rays to determine the spatial distribution of major, minor and trace elements in a sample. By placing a second optics in front of the energy dispersive detector it is possible to create a precise measurement micro volume (Fig.1). The volume size is in the micrometer area. This volume can then be scanned thru the sample either perpendicular to the surface in the topmost layer to get 2D information, or even into the sample to get 3D information about the elemental distribution (Fig.2). This allows for direct 3D measurements without reconstruction algorithms. This method can either be used in the lab using an X-ray tube or for even better results (smaller volume size and lower limits of detection) at a synchrotron facility.

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Fig.1: Overlapping foci of the x-ray optics creating the measurement micro volume.
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Fig.2: 3D scan of a Cu wire cross (red) on a Gd screen (yellow) fixed with sticky tape (blue). Scan size: 230 x 230 x 230 µm³.