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Gauging low-dose X-ray phase-contrast imaging at a single and large propagation distance

Hofmann, R.; Schober, A.; Hahn, S.; Moosmann, J.; Kashef, J.; Hertel, M.; Weinhardt, V.; Hänschke, D.; Helfen, L.; Salazar, I.A.S.; Guigay, J.-P.; Xiao, X.; Baumbach, T.

Abstract (englisch): The interactions of a beam of hard and spatio-temporally coherent X-rays with a soft-matter sample primarily induce a transverse distribution of exit phase variations δϕ (retardations or advancements in pieces of the wave front exiting the object compared to the incoming wave front) whose free-space propagation over a distance z gives rise to intensity contrast gz. For single-distance image detection and |δϕ| ≪ 1 all-order-in-z phase-intensity contrast transfer is linear in δϕ. Here we show that ideal coherence implies a decay of the (shot-)noise-to-signal ratio in gz and of the associated phase noise as z−1/2 and z−1, respectively. Limits on X-ray dose thus favor large values of z. We discuss how a phase-scaling symmetry, exact in the limit δϕ → 0 and dynamically unbroken up to |δϕ| ∼ 1, suggests a filtering of gz in Fourier space, preserving non-iterative quasi-linear phase retrieval for phase variations up to order unity if induced by multi-scale objects inducing phase variations δϕ of a broad spatial frequency spectrum. Such an approach continues to be applicable under an assumed phase-attenuation duality. Using synchrotron radiation, ex and in vivo microtomography on frog embryos exemplifies improved resolution compared to a conventional single-distance phase-retrieval algorithm.

Zugehörige Institution(en) am KIT Institut für Photonenforschung und Synchrotronstrahlung (IPS)
Laboratorium für Applikationen der Synchrotronstrahlung (LAS)
Publikationstyp Zeitschriftenaufsatz
Jahr 2016
Sprache Englisch
Identifikator DOI: 10.1364/OE.24.004331
ISSN: 1094-4087
URN: urn:nbn:de:swb:90-539736
KITopen ID: 1000053973
HGF-Programm 56.03.30; LK 01
Erschienen in Optics express
Band 24
Heft 4
Seiten 4331-4348
Bemerkung zur Veröffentlichung Gefördert durch den KIT-Publikationsfonds
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