In many scientific fields there is a need to three-dimensionally analyse unique and precious samples in a non-destructive way. X-ray based 3D analysis techniques are well-suited to resolve this challenge.
The development of the HERAKLES 3D X-ray scanner at Ghent University created a unique scientific instrument incorporating three complementary methodologies being microscopic X-ray computed tomography (μCT), X-ray fluorescence tomography (XRF-CT) and confocal XRF. The μCT setup yields morphological information on the interior of an object, while the two XRF techniques provide a 3D elemental distribution. Certain applications require high spatial resolution (i.e. submicron) chemical information for solving the scientific question. Not even the current state-of-the-art in laboratory based XRF imaging instruments can achieve scans with this kind of resolution. Synchrotron radiation (SR) based experiments at high-end setups such as beamlines ID16 or ID13 of the European Synchrotron Radiation Facility (ESRF, Grenoble, France) offer the possibility to use a diverse set of X-ray based analysis techniques with a spatial resolution of 100 nm or smaller. A drawback of SR based experiments however is the typically restricted experiment time which is available.
Since high-end SR based and laboratory based setups are working at very different levels of spatial resolution, their techniques are highly complementary. Making use of this complementarity, a procedure based on laboratory methodologies can optimize the output of SR experiments by preliminary characterization of the samples, providing a detailed roadmap for the beamtime and aiding in region of interest (ROI) selection.