Diffractive small angle X-ray scattering imaging for anisotropic structures

Abstract

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 control at micrometer scale must be guaranteed over extended areas. Mesoscale investigations over millimetre sized areas can be performed by scanning small angle X-ray scattering methods (SAXS). However, due to their long measurement times, real time or operando investigations are hindered. Here we present a method based on X-ray diffractive optics that enables the acquisition of SAXS signals in a single shot (few milliseconds) over extended areas. This method is applicable to a wide range of X-ray sources with varying levels of spatial coherence and monochromaticity, as demonstrated from the experimental results. This enables a scalable solution of spatially resolved SAXS.

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

“…The pattern was produced by using e-beam lithography in the case of nanostructures and a conventional UV lithography in the case of microstructures. The patterns of X-ray diffractive elements, consisting of linear 72 or circular gratings, 73 were optimized by introducing interconnects between the catalyst lines, which suppress the off-vertical catalyst movement during MacEtch. 29 In detail, bridges were added to a periodic pattern, and some examples of metal patterns before the etching are reported in the ESI † (Fig.…”

Recent Progress in X-ray and Neutron Phase Imaging with Gratings

“…In this review, introduction to the entire progress in this field was not possible. For other important subjects, such as vector radiography and tensor tomography based on the dark-field signal, combination with energy-resolvable photon-counting image detector, speckle-based approach, coded aperture approach, and so forth, we recommend readers to check the references [99][100][101][102][103][104][105][106]. Finally, we expect that this description of the contents of both X-ray and neutron developments together will be suggestive and stimulating for further progress and application promotion of phase imaging.…”

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

“…where A corresponds to the average intensity of the modulation pattern and V(ξ, ω) the radial visibility as a function of the autocorrelation length ξ. Assuming an oriented fiber structure the angle dependent visibility reduction can be modeled at each angle ω as following 62,64 : 62 . Hence, the data extraction is performed in a similar manner to conventional grating interferometry at each angle ω, i.e., the visibility reduction is given then by:…”

“…The directional information, including the scattering strength and the angle, encoded into the directional DFI uses the hue saturation value (HSV) color space in an analogous manner as adopted in refs. 61,62,64 . The hue corresponds to the characteristic direction of the oriented system; the saturation is set to 1 and the value is defined as the normalized amplitude of the scattering directionality, where the dark areas correspond to the ones with no directional scattering.…”

“…The grating design can be understood as a 2D periodic repetition of a circular unit cell. This is in analogy to a circular grating interferometry approach introduced at highly coherent synchrotron radiation and eventually generalized to polychromatic and incoherent X-ray sources by redesigning the unit cell 61,62 . Here, we adapted the circular grating interferometer idea for application with a cold neutron beam.…”