In 2010 the Chair of X-ray Microscopy was founded as a Fraunhofer endowed chair at the Institute of Physics, Julius-Maximilians-University Würzburg. The head of chair, Prof. Dr. Randolf Hanke, also is the head of the Fraunhofer Project Group Nano X-ray Systems for Material Characterization, which was established in the same year to enable an intense networking between basic research and transfer to application.
Currently, four working groups are established, working on the following research areas: X-ray Microscopy and NanoCT, Phase Contrast Imaging and Holotomography, Material Analytics and Virtual X-ray Physics.
The group X-ray Microscopy and NanoCT focuses on two and three dimensional high resolution imaging using the principle of geometric magnification and cone beam CT. To ensure resolution down to 50 nm, a scanning electron microscope is modified to serve as a nanofocus X-ray source. Research encompasses especially the design of both transmission and reflection targets for x-ray generation and the application of three dimensional imaging in material science.
Based on the X-ray microscopy and nanoCT, phase contrast methods are developed for 2D and 3D imaging. Thus, compared to conventional absorption images, microscopic defects, biological materials, phase boundaries and interfaces are strongly enhanced. In a second step, phase contrast images are used to numerically retrieve the phase shifts of the transmitted wave. When combined with an inverse Radon transform, this technique is called holotomography.
Scattering methods are used to identify inner structural material properties. Small-angle scattering on small structures provides information about size and surface density. In the range of wide angles, diffraction on atomic structures reveals the material’s phase composition, crystal size and space group. By scanning techniques, two- or three-dimensional images of the scattered signals can be recorded in addition to the conventional absorption image.
Wave- and particle-based simulations are carried out with the aim of supporting the image interpretation and processing (e.g. phase retrieval) of sub-micrometer resolution radiographs and tomograms. Further analytical and numerical tools are developed for the analysis of small-angle (SAXS) and ultra small-angle X-ray scattering (USAXS) signals with the purpose of testing new theories of X-ray interaction with matter.
