X-ray grating interferometry requires gratings with periods in the micrometer range and allows the acquisition of the dark-field contrast. The analyzer grating is designed to match the period of the interference pattern in order to translate it into a measurable intensity modulation. In this study, we explore the influence of a sample-induced mismatch between the interference pattern and the analyzer grating on the dark-field contrast. We propose a formula for the calculation of the signal due to a period mismatch and present estimations varying periods and detector pixel size. Furthermore, numerical simulations of the X-ray wave-front demonstrate that the wave-front curvature, described by the lens-term, e.g. behind a parabolic lens or edges of a sample can change the period of the interference pattern. Our results give a concrete explanation for the formation of a dark-field contrast from object edges and thus allow a better understanding of the dark-field signal obtained with a grating interferometer.
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http://dx.doi.org/10.1364/BOE.6.004812 | DOI Listing |
Sci Adv
January 2025
Electrical and Computer Engineering Department, University of California, Los Angeles, CA 90095, USA.
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January 2025
Breast Imaging Department, Red Cross Hospital Munich, Munich, Germany.
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December 2024
Department of Medical Physics and Biomedical Engineering, University College London, London, WC1E 6BT, UK.
X-ray dark-field imaging highlights sample structures through contrast generated by sub-resolution features within the inspected volume. Quantifying dark-field signals generally involves multiple exposures for phase retrieval, separating contributions from scattering, refraction, and attenuation. Here, we introduce an approach for non-interferometric X-ray dark-field imaging that presents a single-parameter representation of the sample.
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Institute of Energy: Sustainability, Environment, and Equity, Stony Brook University, Stony Brook, New York 11794, United States.
Significant demand for lithium-ion batteries necessitates alternatives to Co- and Ni-based cathode materials. Cation-disordered materials using earth-abundant elements are being explored as promising candidates. In this paper, we demonstrate a coprecipitation synthetic approach that allows direct preparation of disordered rocksalt LiFeTiO (r-LFTO·C) and spinel structured hybrid LiFeTiO·C (s-LFTO·C) nanoparticles with a conformal conductive carbon coating.
View Article and Find Full Text PDFACS Omega
November 2024
Advanced Laboratory of Electro-Optics (ALEO), Department of Applied Physics/Electro-Optics Engineering, Lev Academic Center, Jerusalem 9116001, Israel.
Plasmonic nanostructure arrays, designed for performance as pixels in an advanced SERS imaging device, were fabricated by gallium focused ion beam (FIB). Though the FIB is best suited for etching holes and negative structures, our previously reported simulations favor protrusions. Herein, we report on the FIB methodology to "sculpt" positive structures by "ion-blasting" away the surrounding material.
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