title: Beamstop-based low-background ptychography to image weakly scattering objects.
abstract: In recent years, X-ray ptychography has been established as a valuable tool for high-resolution imaging. Nevertheless, the spatial resolution and sensitivity in coherent diffraction imaging are limited by the signal that is detected over noise and over background scattering. Especially, coherent imaging of weakly scattering specimens suffers from incoherent background that is generated by the interaction of the central beam with matter along its propagation path in particular close to and inside of the detector. Common countermeasures entail evacuated flight tubes or detector-side beamstops, which improve the experimental setup in terms of background reduction or better coverage of high dynamic range in the diffraction patterns. Here, we discuss an alternative approach: we combine two ptychographic scans with and without beamstop and reconstruct them simultaneously taking advantage of the complementary information contained in the two scans. We experimentally demonstrate the potential of this scheme for hard X-ray ptychography by imaging a weakly scattering object composed of catalytic nanoparticles and provide the analysis of the signal-to-background ratio in the diffraction patterns.
authors.affiliation: Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany. Electronic address: juliane.reinhardt@desy.de.
authors.forename: Juliane
authors.initials: J
authors.lastname: Reinhardt
authors.affiliation: Institute of Structural Physics, Technische Universität Dresden, D-01062 Dresden, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Hoppe
authors.affiliation: Institute for Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Hofmann
authors.affiliation: Center for Electron Nanoscopy and Department of Physics, Technical University of Denmark, DK-2800 Lyngby, Denmark.
authors.forename: Christian D
authors.initials: CD
authors.lastname: Damsgaard
authors.affiliation: Institute of Structural Physics, Technische Universität Dresden, D-01062 Dresden, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Patommel
authors.affiliation: Institute of Structural Physics, Technische Universität Dresden, D-01062 Dresden, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Baumbach
authors.affiliation: Institute for Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany.
authors.forename: Sina
authors.initials: S
authors.lastname: Baier
authors.affiliation: Institute for Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany.
authors.forename: Amélie
authors.initials: A
authors.lastname: Rochet
authors.affiliation: Institute for Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany.
authors.forename: Jan-Dierk
authors.initials: JD
authors.lastname: Grunwaldt
authors.affiliation: Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany.
authors.forename: Gerald
authors.initials: G
authors.lastname: Falkenberg
authors.affiliation: Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany; Department Physik, Universität Hamburg, Luruper Chaussee 149, D-22761 Hamburg, Germany.
authors.forename: Christian G
authors.initials: CG
authors.lastname: Schroer
keywords: Background scattering; Beamstop; High resolution; Nanoparticles; Ptychography; Signal-to-noise