Gauging low-dose X-ray phase-contrast imaging at a single and large propagation distance
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...
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| Main Authors: | , , , , , , , , , , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
19 Feb 2016
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| In: |
Optics express
Year: 2016, Volume: 24, Issue: 4, Pages: 4331-4348 |
| ISSN: | 1094-4087 |
| DOI: | 10.1364/OE.24.004331 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1364/OE.24.004331 Verlag, lizenzpflichtig, Volltext: https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-4-4331 
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| Author Notes: | Ralf Hofmann, Alexander Schober, Steffen Hahn, Julian Moosmann, Jubin Kashef, Madeleine Hertel, Venera Weinhardt, Daniel Hänschke, Lukas Helfen, Iván A. Sánchez Salazar, Jean-Pierre Guigay, Xianghui Xiao, Tilo Baumbach |
| Summary: | 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. |
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| Item Description: | Gesehen am 19.05.2020 |
| Physical Description: | Online Resource |
| ISSN: | 1094-4087 |
| DOI: | 10.1364/OE.24.004331 |