TY - JOUR A1 - Shashev, Yury A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Müller, Bernd R. A1 - Bruno, Giovanni T1 - Improving the visibility of phase gratings for Talbot-Lau X-ray imaging JF - Materials testing : Materialprüfung ; materials and components, technology and application N2 - Talbot-Lau interferometry provides X-ray imaging techniques with significant enhancement of the radiographic contrast of weakly absorbing objects. The grating based technique allows separation of absorption, refraction and small angle scattering effects. The different efficiency of rectangular and triangular shaped phase gratings at varying detector distances is investigated. The interference patterns (Talbot carpets) are modeled for parallel monochromatic radiation and measured by synchrotron radiation. In comparison to rectangular shapes of phase gratings much higher visibility is obtained for triangular shapes which yield enhanced contrast of a glass capillary test specimen. KW - Talbot-Lau interferometry KW - phase grating KW - synchrotron imaging KW - visibility KW - X-ray refraction Y1 - 2016 U6 - https://doi.org/10.3139/120.110948 SN - 0025-5300 VL - 58 SP - 970 EP - 974 PB - Hanser CY - München ER - TY - JOUR A1 - Shashev, Yury A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Evsevleev, Sergei A1 - Müller, Bernd R. A1 - Osenberg, Markus A1 - Manke, Ingo A1 - Hentschel, Manfred P. A1 - Bruno, Giovanni T1 - Optimizing the visibility of X-ray phase grating interferometry JF - Materials testing : Materialprüfung ; materials and components, technology and application N2 - The performance of grating interferometers coming up now for imaging interfaces within materials depends on the efficiency (visibility) of their main component, namely the phase grating. Therefore, experiments with monochromatic synchrotron radiation and corresponding simulations are carried out. The visibility of a phase grating is optimized by different photon energies, varying detector to grating distances and continuous rotation of the phase grating about the grid lines. Such kind of rotation changes the projected grating shapes, and thereby the distribution profiles of phase shifts. This yields higher visibilities than derived from ideal rectangular shapes. By continuous grating rotation and variation of the propagation distance, we achieve 2D visibility maps. Such maps provide the visibility for a certain combination of grating orientation and detector position. Optimum visibilities occur at considerably smaller distances than in the standard setup. KW - X-ray imaging KW - grating interferometry KW - Talbot-Lau interferometer KW - X-ray refraction KW - X-ray phase contrast Y1 - 2017 U6 - https://doi.org/10.3139/120.111097 SN - 0025-5300 VL - 59 SP - 974 EP - 980 PB - Hanser CY - München ER - TY - JOUR A1 - Kupsch, Andreas A1 - Mueller, Bernd R. A1 - Lange, Axel A1 - Bruno, Giovanni T1 - Microstructure characterisation of ceramics via 2D and 3D X-ray refraction techniques JF - Journal of the European Ceramic Society N2 - 3D imaging techniques are very fashionable nowadays, and allow enormous progress in understanding ceramic microstructure, its evolution, and its link to mechanical, thermal, and transport properties. In this feature article, we report the use of a powerful, yet not so wide-spread, set of X-ray techniques based on refraction effects. X-ray refraction allows determining internal specific surface (surface per unit volume) in a non-destructive fashion, position and orientation sensitive, and with a nanometric detectability. While the techniques are limited by the X-ray absorption of the material under investigation, we demonstrate showcases of ceramics and composite materials, where understanding of process parameter influence or simply of microstructural parameters could be achieved in a way unrivalled even by high-resolution techniques such as electron microscopy or computed tomography. (C) 2016 Elsevier Ltd. All rights reserved. KW - X-ray refraction KW - Porosity KW - Specific surface KW - Crack detection KW - Composites Y1 - 2017 U6 - https://doi.org/10.1016/j.jeurceramsoc.2016.12.031 SN - 0955-2219 SN - 1873-619X VL - 37 SP - 1879 EP - 1889 PB - Elsevier CY - Oxford ER -