X-ray coherent diffraction imaging: Sequential inverse problems simulation

Abstract Improvement of spatial coherence in third generation synchrotron beamlines made possible the development of X-ray plane-wave coherent diffraction imaging technique (plane-wave cdi ), which enables 3D imaging at nanometric resolution. In this work, we first simulated the influence of detector geometry by comparing reconstruction quality of planar samples made of gold nanoparticles. We compared a commercially available detector geometry with the next Medipix3-based large area detector designed for the next fourth generation Brazilian synchrotron, sirius . The spatial resolution was highly improved, from 7.2 nm for the commercial geometry to 4.8 nm for the Medipix3 detector by keeping the same global image quality. Finally, global image qualities were compared by adjusting the sample-to-detectors distances at a given spatial resolution. For thick samples reconstruction at such high nanometric resolutions, the main limitation of current reconstruction approaches are due to the complex wave propagation within the sample, given by the inhomogeneous Helmholtz equation. We proposed an iterative method to reconstruct the complex refraction index. This method enables to keep the image quality almost constant beyond the resolution limit for thick samples made of gold nanoparticles in water.