Dual phase grating interferometer for tunable dark-field sensitivity

Kagias, Matias; Wang, Zhentian; Jefimovs, Konstantins; Stampanoni, Marco

doi:10.1063/1.4973520

Cited by 54 publications

(65 citation statements)

References 26 publications

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“…[32][33][34][35] Darkfield imaging can also provide 3D microstructural information in tomographic mode. [36][37][38] Colloidal systems [39][40][41][42][43][44] and powders 45 were investigated with this imaging method to demonstrate its capability to provide quantitative results for example on the radius size of the colloid particles. Yang et al 46 showed that X-ray dark-field imaging is able to visualize the transport of water in thin samples (2 mm) of porous mortar.…”

mentioning

confidence: 99%

Selective Visualization of Water in Fuel Cell Gas Diffusion Layers with Neutron Dark-Field Imaging

Siegwart

Harti

Manzi-Orezzoli

et al. 2019

J. Electrochem. Soc.

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Visualizing the water distribution in porous gas diffusion layers (GDLs) of operating polymer electrolyte fuel cells (PEFCs) is indispensable to understand the impact of water management on performance. For this purpose, neutron and X-ray transmission imaging have been used for nearly two decades. Certain limitations inherent to attenuation based imaging methods can be overcome by applying neutron dark-field imaging, which has the ability to selectively visualize structures in the micrometer size range. In this study, we compare dark-field images and transmission images of GDLs filled with water through an injection channel. The high contrast of the dark-field value between a heavy water filled and a dry GDL is suitable to reveal water distribution patterns in the GDL. The water present in the 1 mm wide water injection channel of the test device does not alter the dark-field signal, as this technique is selectively sensitive to microstructures. Therefore, neutron dark-field imaging can be applied for the selective analysis of the water distribution in the GDL overlapping with channel water. In addition to the selective visualization of water distributed in a GDL, we show that neutron dark-field imaging can also be used to visualize GDL damages.

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mentioning

confidence: 99%

Selective Visualization of Water in Fuel Cell Gas Diffusion Layers with Neutron Dark-Field Imaging

Siegwart

Harti

Manzi-Orezzoli

et al. 2019

J. Electrochem. Soc.

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“…The combination of unconventional processing and the freedom from microelectronics constrains enrich the spectrum of capabilities and give a new life to the "old silicon material", with revolutionizing advancements in nanotechnology [37]. We recently reported about micro-and nano-fabrication processing for X-ray gratings, including lithography [89], dry [37,90,91] and wet etching methods [39], Au electroplating [22], Ir atomic layer deposition [92] and metal casting [19,20]. The use of MacEtch as a microfabrication process for X-ray optical devices was first reported in 2014 for Fresnel zone plate structures [17,18].…”

Section: Silicon Based Microfabrication Of X-ray Opticsmentioning

confidence: 99%

Microfabrication of X-ray Optics by Metal Assisted Chemical Etching: A Review

Romano

Stampanoni

2020

Micromachines

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High-aspect-ratio silicon micro- and nanostructures are technologically relevant in several applications, such as microelectronics, microelectromechanical systems, sensors, thermoelectric materials, battery anodes, solar cells, photonic devices, and X-ray optics. Microfabrication is usually achieved by dry-etch with reactive ions and KOH based wet-etch, metal assisted chemical etching (MacEtch) is emerging as a new etching technique that allows huge aspect ratio for feature size in the nanoscale. To date, a specialized review of MacEtch that considers both the fundamentals and X-ray optics applications is missing in the literature. This review aims to provide a comprehensive summary including: (i) fundamental mechanism; (ii) basics and roles to perform uniform etching in direction perpendicular to the <100> Si substrate; (iii) several examples of X-ray optics fabricated by MacEtch such as line gratings, circular gratings array, Fresnel zone plates, and other X-ray lenses; (iv) materials and methods for a full fabrication of absorbing gratings and the application in X-ray grating based interferometry; and (v) future perspectives of X-ray optics fabrication. The review provides researchers and engineers with an extensive and updated understanding of the principles and applications of MacEtch as a new technology for X-ray optics fabrication.

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“…The fabricated gratings have been successfully applied in a recently developed x-ray interferometer based on two phase shifting gratings that can be used for differential phase contrast as well as dark-field X-ray imaging. A thorough description of the interferometer can be found here [3]. The experimental setup is presented in Figure 5.…”

Section: X-ray Imaging Experimentsmentioning

confidence: 99%

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

et al. 2017

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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 not fully flat due to any kind of defects, such as bowing/warpage or remaining topography of the surface in case of overlay exposures, noticeable linewidth variations or complete failure of lithography step will occur.We utilized the newly developed Displacement Talbot lithography to pattern gratings with equal lines and spaces and periods in the range of 1.0 to 2.4 µm. The exposures in this lithography process do not require contact between the mask and the wafer, which makes it essentially insensitive to surface planarity and enables exposures with very high linewidth uniformity on thin and even slightly deformed wafers. We demonstrated pattern transfer of such exposures into Si substrates by reactive ion etching using the Bosch process. An etching depth of 30 m or more for the whole range of periods was achieved, which corresponds to very high aspect ratios up to 60:1. The application of the fabricated gratings in phase contrast x-ray imaging is presented.

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Dual phase grating interferometer for tunable dark-field sensitivity

Cited by 54 publications

References 26 publications

Selective Visualization of Water in Fuel Cell Gas Diffusion Layers with Neutron Dark-Field Imaging

Selective Visualization of Water in Fuel Cell Gas Diffusion Layers with Neutron Dark-Field Imaging

Microfabrication of X-ray Optics by Metal Assisted Chemical Etching: A Review

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

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