Dark-field hyperspectral X-ray imaging

Abstract

In recent times, there has been a drive to develop nondestructive X-ray imaging techniques that provide chemical or physical insight. To date, these methods have generally been limited; either requiring raster scanning of pencil beams, using narrow bandwidth radiation and/or limited to small samples. We have developed a novel full-field radiographic imaging technique that enables the entire physiochemical state of an object to be imaged in a single snapshot. The method is sensitive to emitted and scattered radiation, using a spectral imaging detector and polychromatic hard X-radiation, making it particularly useful for studying large dense samples for materials science and engineering applications. The method and its extension to three-dimensional imaging is validated with a series of test objects and demonstrated to directly image the crystallographic preferred orientation and formed precipitates across an aluminium alloy friction stir weld section.

Microscopic dual‐energy CT (microDECT): a flexible tool for multichannelex vivo3D imaging of biological specimens

“…Besides dual-energy CT, there are other approaches to extract spectral information from microCT images, including one based on the use of spectral detectors (Johnson, 2012). Recent developments of spectral detectors for laboratory-based x-ray imaging setups might offer even more options for discriminating multiple elements at a time without any need for sample preparation (Jacques et al, 2013;Egan et al, 2014;Egan et al, 2015). In addition, triple and multienergy imaging approaches will allow for decomposition of three or more materials (Granton et al, 2008;Fornaro et al, 2011).…”

Hyperspectral microscopy as an analytical tool for nanomaterials

“…The term ‘hyperspectral’, rather than just ‘spectral’, refers to the range of wavelengths measured, which typically includes near‐infrared, visible, and sometimes near‐ultraviolet spectra. The use of dark‐field imaging enhances the effectiveness of the technique since it decreases the background signal and emphasizes materials that scatter the most light, and such scattering spectra are more uniquely characteristic of a given material …”

Resolving Time-dependent Evolution of Pore-Scale Structure, Permeability and Reactivity using X-ray Microtomography

“…Technological evolution of instrumentation and detectors as well as the development of new reconstruction procedures continues to increase the capacities and utility of XMT. For example, the development of ultra-fast tomography allows for tracking of very rapid dynamic processes (e.g., Mokso et al 2011;Armstrong et al 2014a,b), as time needed to obtain a full 3-D data set can be less than 1 s. Techniques based on the energy dependence of the attenuation coeffi cient, such as dual-energy microtomography, can reveal the distribution of distinctive chemical compositions within a sample, as well as X-ray fl uorescence microtomography (e.g., Van Geet et al 2000;Egan et al 2014). Detailed reviews of XMT development and applications are provided in Van Geet et al (2001), Wildenschild et al (2002), Carlson et al (2003), Carlson (2006), Blunt et al (2013), Cnudde and Boone (2013) and Wildenschild and Sheppard (2013).…”