Wavelength-dispersive dark-field contrast: micrometre structure resolution in neutron imaging with gratings

Abstract

Dark-field imaging using grating interferometers has been proven to have a high potential for applications in engineering, magnetism, and soft matter and biophysics, as well as in medicine with both neutrons and X-rays. The access to spatially resolved small-angle scattering information in neutron dark-field imaging provides information about structures beyond direct spatial image resolution. The dark-field contrast modality is hence a valuable tool for materials science based on neutron imaging. This is underlined by the success of the method, despite its current limitation to qualitative scattering information.Here it is demonstrated how a wavelength-dispersive approach allows such drawbacks to be overcome by providing quantitative structure size information and hence can introduce novel possibilities and insights for materials science.

Small Angle Scattering in Neutron Imaging—A Review

“…Similar studies have been performed also with the SEM-DFI approach, however, here nanoparticle systems around 100nm in size have been studied as reference systems and provide similar results as with the Talbot-Lau grating interferometer, but on a complementary length scale [34,44,[46][47][48]. An example of a study on metallic welds is presented in Figure 6.…”

“…Similar results have been reported later at other facilities [45], underlining a fast spread of the method and its potential. In one case sedimentation effects could be observed [44] (Figure 5a), while in a subsequent work the sedimentation and quasi crystallization of micrometer particles in solution could be studied in detail and the spatial resolution enabled to distinguish several different phases in the system [46] (Figure 5b). This latter study already utilized an upgraded Talbot-Lau grating interferometer, in which for the extension of the range in pure sample distance scan, the used order of the Talbot distance was increased, in order to enable extended scanning and investigated size range.…”

“…The initial proof of principle has been realized through wavelength and sample distance scans to extract the particle size and concentration of spherical micrometer sized particles dispersed in water [44] (Figure 5a). Similar results have been reported later at other facilities [45], underlining a fast spread of the method and its potential.…”

“…Therefore, the methods enable studies of inhomogeneity driven or creating processes and states. ; results corresponding to form factor of spherical particles with dimeter of 2 µm measured (a2); (a3,a4) corresponding dark-field images at 3.3 Å and 5 Å, respectively [44]; (b) DFI of polystyrene spheres sedimenting in an aqueous dilution where a diluted phase a concentrated phase and a quasi-crystalline phase can be identified and in particular a depletion zone (C) between high concentration and crystallization regions is found [46]; (a1) to (a4) are reproduced with permission of the International Union of Crystallography from [44].…”

Non-Destructive Testing of Archaeological Findings by Grating-Based X-Ray Phase-Contrast and Dark-Field Imaging

“…A smaller sensitivity leads to a reduced dark-field signal. The amount of reduction depends on the size and shape of the scattering structures [39]. There might be a chance to suppress the influence of soil particles, partially in order to reveal scattering structures of quite different sizes than the soil particles.…”