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Tunable X-ray dark-field imaging for sub-resolution feature size quantification in porous media

X-ray computed micro-tomography typically involves a trade-off between sample size and resolution, complicating the study at a micrometer scale of representative volumes of materials with broad feature size distributions (e.g. natural stones). X-ray dark-field tomography exploits scattering to probe sub-resolution features, promising to overcome this trade-off. In this work, we present a quantific

Simultaneous Reciprocal and Real Space X-Ray Imaging of Time-Evolving Systems

Imaging the (sub)micron scale over large areas with high temporal resolution becomes increasingly necessary for the development and investigation of novel materials under realistic operation conditions. Small angle x-ray scattering imaging methods provide micro- and nanoscale structural information of materials. A fundamental shortcoming of such methods is the long acquisition time required to inv

Metal assisted chemical etching of silicon in the gas phase : A nanofabrication platform for X-ray optics

High aspect ratio nanostructuring requires high precision pattern transfer with highly directional etching. In this work, we demonstrate the fabrication of structures with ultra-high aspect ratios (up to 10 000 : 1) in the nanoscale regime (down to 10 nm) by platinum assisted chemical etching of silicon in the gas phase. The etching gas is created by a vapour of water diluted hydrofluoric acid and

Operando Visualization of Water Distribution in Gas Diffusion Media of PEFCs with an Optimized Neutron Grating Interferometer

We demonstrated the use of a neutron grating interferometer setup (nGI) with a significantly improved contrast-to-noise ratio of the operando dark-field (DF) contrast visualization of water in gas diffusion media (GDM). The nGI parameters were optimized in such a way that we could perform DF imaging of a fully operational fuel cell including two GDM layers (anode and cathode side). The DF contrast

X-ray scattering tensor tomography with circular gratings

Three dimensional (3D) information of the microstructure organization of various relevant materials in industry and nature is fundamental to master the understanding of their macroscopic properties. X-ray scattering tensor tomography provides 3D directional information on unresolved microstructures in large volumes, facilitating the investigation of the microstructural organization in statisticall

Characterization of oriented microstructures through anisotropic small-angle scattering by 2D neutron dark-field imaging

Within neutron imaging, different methods have been developed with the aim to go beyond the conventional contrast modalities, such as grating interferometry. Existing grating interferometers are sensitive to scattering in a single direction only, and thus investigations of anisotropic scattering structures imply the need for a circular scan of either the sample or the gratings. Here we propose an

Diffractive small angle X-ray scattering imaging for anisotropic structures

Insights into the micro- and nano-architecture of materials is crucial for understanding and predicting their macroscopic behaviour. In particular, for emerging applications such as meta-materials, the micrometer scale becomes highly relevant. The micro-architecture of such materials can be tailored to exhibit specific mechanical, optical or electromagnetic behaviours. Consequently, quality contro

Fabrication of Au gratings by seedless electroplating for X-ray grating interferometry

High quality gratings are among the key elements for successful imaging with X-ray grating interferometry. Grating fabrication, specifically of absorption gratings, with high aspect ratio and large area, is a great challenge from a microfabrication point of view. In this paper the fabrication of absorption gratings by seedless electroplating of gold in high aspect ratio silicon moulds that are fab

Towards sub-micrometer high aspect ratio X-ray gratings by atomic layer deposition of iridium

X-ray grating interferometry is an excellent technique for X-ray phase contrast imaging and X-ray wavefront sensing with applications in materials science, biology and medical diagnosis. Among other requirements, the method depends on the availability of highly X-ray absorbing metallic gratings. Here, we report on the fabrication and characterization of high aspect ratio iridium gratings with a pe

Interpretation and Utility of the Moments of Small-Angle X-Ray Scattering Distributions

Small angle X-ray scattering has been proven to be a valuable method for accessing structural information below the spatial resolution limit implied by direct imaging. Here, we theoretically derive the relation that links the subpixel differential phase signal provided by the sample to the moments of scattering distributions accessible by refraction sensitive X-ray imaging techniques. As an import

High aspect ratio silicon structures by displacement Talbot lithography and Bosch etching

Despite the fact that the resolution of conventional contact/proximity lithography can reach feature sizes down to ∼0.5-0.6 micrometers, the accurate control of the linewidth and uniformity becomes already very challenging for gratings with periods in the range of 1-2 μm. This is particularly relevant for the exposure of large areas and wafers thinner than 300 μm. If the wafer or mask surface is n

Anisotropic hydrodynamic function of dense confined colloids

Dense colloidal dispersions exhibit complex wave-vector-dependent diffusion, which is controlled by both direct particle interactions and indirect nonadditive hydrodynamic interactions mediated by the solvent. In bulk the hydrodynamic interactions are probed routinely, but in confined geometries their studies have been hitherto hindered by additional complications due to confining walls. Here we s

Sub-pixel correlation length neutron imaging : Spatially resolved scattering information of microstructures on a macroscopic scale

Neutron imaging and scattering give data of significantly different nature and traditional methods leave a gap of accessible structure sizes at around 10 micrometers. Only in recent years overlap in the probed size ranges could be achieved by independent application of high resolution scattering and imaging methods, however without providing full structural information when microstructures vary on

Dual phase grating interferometer for tunable dark-field sensitivity

Hard X-ray dark-field and phase contrast imaging using grating interferometry have shown great potential for medical and industrial applications. However, the wide spread applicability of the method is challenged by a number of technical related issues such as relatively low dose and flux efficiency due to the absorption grating, fabrication of high quality absorption gratings, slow data acquisiti

High aspect ratio metal microcasting by hot embossing for X-ray optics fabrication

Metal microstructured optical elements for grating-based X-ray phase-contrast interferometry were fabricated by using an innovative approach of microcasting: hot embossing technology with low melting temperature (280 °C) metal alloy foils and silicon etched templates. A gold-tin alloy (80 wt% Au/20 wt% Sn) was used to cast micro-gratings with pitch sizes in the range of 2 to20 μm and depth of the

Micrometer-resolution imaging using MÖNCH : Towards G2-less grating interferometry

MÖNCH is a 25 mm-pitch charge-integrating detector aimed at exploring the limits of current hybrid silicon detector technology. The small pixel size makes it ideal for high-resolution imaging. With an electronic noise of about 110 eV r.m.s., it opens new perspectives for many synchrotron applications where currently the detector is the limiting factor, e.g. inelastic X-ray scattering, Laue diffrac

Single shot x-ray phase contrast imaging using a direct conversion microstrip detector with single photon sensitivity

X-ray phase contrast imaging enables the measurement of the electron density of a sample with high sensitivity compared to the conventional absorption contrast. This is advantageous for the study of dose-sensitive samples, in particular, for biological and medical investigations. Recent developments relaxed the requirement for the beam coherence, such that conventional X-ray sources can be used fo