SKM 2023 – wissenschaftliches Programm
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 9: Microscopy and Tomography with X-ray Photons, Electrons, Ions and Positron
KFM 9.12: Vortrag
Mittwoch, 29. März 2023, 12:55–13:15, POT 106
Illumination corrected X-ray near-field microscopy — •Thea Engler1,2, Johannes Hagemann1, Christian G. Schroer1,2, and Mathias Trabs3 — 1Deutsches Elektronen-Synchrotron, DESY, Germany — 2Universität Hamburg, Germany — 3Karlsruhe Institut of Technology, KIT, Germany
At synchrotron facilities, such as Petra III at DESY, small objects (μm) can be imaged with X-ray propagation-based phase-contrast imaging, i.e. near-field holography (NFH).
Reaching high resolution involves the use of nano-focusing optics. The imperfections of these optics cause aberrations in the illumination of the object and also upon further propagation in the measured hologram of the object. To correct the hologram for these artifacts, a flat-field correction must be applied. Considering a temporally stable beam, the hologram is divided by an empty-beam image, i.e. an image of the illumination without the object. With the common flat-field correction, the hologram is not fully corrected for the illumination function since the division is performed only in intensities in the detector plane.
Instead, the division of illumination and object should be performed in terms of complex wavefields in the sample plane, where the object transmission function physically interacts with the illumination function. Using a simulated dataset, we develop an algorithmic scheme using the recently proposed refractive formulation to take the illumination during the phase retrieval process properly into account.