Dark-field X-ray imaging of unsaturated water transport in porous materials

Yang, Fei; Prade, Friedrich; Griffa, Michele; Jerjen, Iwan; Bella, Carmelo Di; Herzen, Julia; Sarapata, Adrian; Pfeiffer, Franz; Lura, Pietro

doi:10.1063/1.4898783

Cited by 46 publications

(35 citation statements)

References 38 publications

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“…These two techniques work with conventional x-ray sources and can be adapted to existing medical imaging systems [6]. Several groups have shown promising results for medical imaging applications [7][8][9][10][11] as well as for non-destructive testing [12][13][14][15][16]. For quality assessment of a Talbot-Lau interferometer, the visibility is a crucial quantity.…”

Section: Introductionmentioning

confidence: 99%

Designing the phase grating for Talbot-Lau phase-contrast imaging systems: a simulation and experiment study

et al. 2016

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Abstract:The performance of a Talbot-Lau interferometer depends to a great extent on its visibility. This means, to obtain high quality phase-contrast and dark-field images a high visibility is mandatory. Several parameters influence the visibility of such a system, like for example the x-ray spectrum, the inter-grating distances or the parameters of the three gratings. In this multidimensional space, wave field simulations help to find the optimal combination of the grating specifications to construct a setup with a high visibility while retaining a fixed angular sensitivity. In this work we specifically analyzed the influence of the G1 grating duty cycle in simulations and experiments. We show that there is a lot of room for improvement by varying the duty cycle of the phase-shifting grating G1. As a result, by employing a third-integer duty cycle we can increase the visibility to up to 53 % in a laboratory setup with a polychromatic spectrum. The achieved visibility is more than two times higher compared to the result with a standard-type setup. This visibility gain allows a dose reduction by a factor of 5 preserving the same image quality. "Energy-resolved visibility analysis of grating interferometers operated at polychromatic X-ray sources," Opt.

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Section: Introductionmentioning

confidence: 99%

Designing the phase grating for Talbot-Lau phase-contrast imaging systems: a simulation and experiment study

et al. 2016

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“…Subsequently, filling of the stress cracks during water uptake would lead to a smaller electron density difference, and the dark-field signal would diminish as was ob- served. A recent study of water uptake in porous media found a similar decrease in dark-field signal when the sub-resolution pores were filled with water [36]. According to [37] stress cracks within the barley endosperm do not seem to affect the ability to germinate .…”

Section: Discussionmentioning

confidence: 88%

Quantitative in-situ monitoring of germinating barley seeds using X-ray dark-field radiography

Nielsen

Damkjær

Feidenhans’l

2017

Journal of Food Engineering

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During production of malt from barley seeds, cell walls and starch granules in the endosperm are degraded. Although this modification process is important for malt quality, the modification patterns of individual barley seeds have yet to be reported. The use of destructive microscopy methods have previously limited the investigations to ensemble averages.X-ray dark-field radiography is a recent non-destructive imaging method which is sensitive to microstructural variations. In this study, the method was applied for quantitative in-situ monitoring of barley seeds. Microstructural changes relating to water uptake and modification were monitored over a 43-55 h period.Sub-resolution stress cracks as well as a dark-field signal believed to originate from starch granules were detected. The evolution of the dark-field signal followed the known modification pattern in barley seeds. Through image analysis, quantitative parameters describing the movement of the front of the observed pattern were obtained.Based on these findings, X-ray dark-field radiography presents a possible novel approach to monitor the modification of germinating barley seeds.

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“…have shown that water displacements in a porous material with pore size distribution covering a range falling below the spatial resolution lead to a decrease in the local multiple scattering, thus enhancing the contrast between regions of the material with empty pores and regions with partial or complete saturation (Yang et al ., ). The proof‐of‐concept of that approach was implemented via Talbot–Lau interferometry (Yang et al ., ). Another possible implementation of that approach could be based upon the edge illumination technique (Endrizzi et al ., ).…”

Section: Introductionmentioning

confidence: 97%

Visualization of water drying in porous materials by X‐ray phase contrast imaging

Yang

Griffa

Bonnin

et al. 2016

Journal of Microscopy

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We present in this study results from X-ray tomographic microscopy with synchrotron radiation performed both in attenuation and phase contrast modes on a limestone sample during two stages of water drying. No contrast agent was used in order to increase the X-ray attenuation by water. We show that only by using the phase contrast mode it is possible to achieve enough water content change resolution to investigate the drying process at the pore-scale. We performed 3D image analysis of the time-differential phase contrast tomogram. We show by the results of such analysis that it is possible to obtain a reliable characterization of the spatial redistribution of water in the resolved pore system in agreement with what expected from the theory of drying in porous media and from measurements performed with other approaches. We thus show the potential of X-ray phase contrast imaging for pore-scale investigations of reactive water transport processes which cannot be imaged by adding a contrast agent for exploiting the standard attenuation contrast imaging mode.

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Dark-field X-ray imaging of unsaturated water transport in porous materials

Cited by 46 publications

References 38 publications

Designing the phase grating for Talbot-Lau phase-contrast imaging systems: a simulation and experiment study

Designing the phase grating for Talbot-Lau phase-contrast imaging systems: a simulation and experiment study

Quantitative in-situ monitoring of germinating barley seeds using X-ray dark-field radiography

Visualization of water drying in porous materials by X‐ray phase contrast imaging

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