Grating-based Talbot-Lau X-ray Interferometry is a novel imaging modality. Compared to standard absorption X-ray imaging, it enables the acquisition of differential phase contrast images. These images correspond to the electron density of the scanned specimen. Furthermore, so-called dark-field images are obtained. These images can visualize density inhomogeneities at micrometer scale. The goal of the project is to improve the setup of Talbot-Lau X-ray Imaging systems. So far the correlation between the different variables of such a system especially with polychromatic X-ray spectra is not known yet. Thus, the setup should be simulated and optimized to find the ideal setup with respect to certain structures in the object and the resulting images.