One of the main potential benefits of using brilliant X-ray beams for diagnostic applications is the development of novel contrast modalities that offer better soft tissue sensitivity. In this context, the clinically oriented diagnostic projects in the Research Areas C.1 & C.2 will focus predominantly on evaluating the potential of a new method for differential phase-contrast X-ray imaging.
This approach is based on X-ray optical transmission gratings. The goal of the proposed project here is to develop dedicated grating optics for these application-oriented projects. We want to push and further develop the currently used fabrication protocol for silicon-based (and partially gold-filled) one-dimensional grating structures to allow for (a) larger fields-of-view and (b) higher X-ray energy. The first goal is motivated by the requirement to be able to image small-animal-mouse models (i.e. mice and rats) and clinical specimens (e.g. excised full human breast specimens) and we shall push to achieve grating structures with an active area of 12 x 12 cm2 (presently existing structures are limited to 6 x 6 cm2). The second goal, to yield grating structures for proof-of-principle studies at clinically relevant X-ray energies (> 50 keV) will require to fabricate high-aspect-ratio structures with periods in the few micron range and heights approaching hundred microns.
We identified LIGA (X-ray lithography and photo-plating) as the ideal process to achieve the results and will collaborate with the Institute for Microstructures (J. Mohr / V. Seile) at the Karlsruhe Institute for Technology. Benchmarking experiments to test and optimise the fabrication protocols involve testing of structures at synchrotron facilities in Hamburg (PETRA III) and Grenoble (ESRF).