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Application Specific Integrated Circuits for Direct X-Ray and Gamma-Ray Conversion in Security Applications
Published in Choi Jung Han, Iniewski Krzysztof, High-Speed and Lower Power Technologies, 2018
Krzysztof Iniewski, Chris Siu, Adam Grosser
It has been shown very recently that a traditional high-energy X-ray system can capture scattered X-rays to deliver 3D images with structural or chemical information in each voxel. This type of imaging can be used to separate and identify chemical species in bulk objects with no special sample preparation. Defining hyperspectral technology precisely is difficult as it is a relatively new concept that as a minimum it should contain 100 energy bins. In addition, hyperspectral technology takes advantage of measurement orthogonality.
Automated Systems in Other Domains
Published in Charles E. Billings, Aviation Automation: The Search for A Human-Centered Approach, 2018
The Therac-25 is a linear accelerator that generates high-energy (up to 25 MeV) electrons. The electron beam, properly modulated, is used to treat superficial tumors. Alternatively, the electron beam is directed at a metallic target in which high-energy x-ray photons are generated. The x-ray beam is collimated and can be used to treat tumors in deeper tissues.
CdTe and CdZnTe Small Pixel Imaging Detectors
Published in Salah Awadalla, Krzysztof Iniewski, Solid-State Radiation Detectors, 2017
High-energy x-rays have the ability to penetrate deeply into materials, allowing the examination of dense objects such as welds in steel and geological core sections and the internal observation of chemical reactions inside machinery. Different experimental techniques such as x-ray fluorescence imaging (XRF) and x-ray diffraction imaging are powerful experimental techniques that provide qualitative information about the elemental composition and internal stresses and strains within a specimen. The use of these techniques requires x-ray detectors that are sensitive over a broad range of energies, such as the HEXITEC detector. In this example, spectroscopic imaging techniques developed by Jacques et al. [45,46] at the University of Manchester for the HEXITEC detector are used to characterize an important modern joining technique, friction stir welding (FSW) [47,48]. The use of spectroscopic imaging provides important information on not only the reorganization of the crystal lattice within the central weld but also the redistribution of impurities around the weld.
Electromagnetic (EM) sensor measurement for residual stress characterisation in welded steel plates
Published in Nondestructive Testing and Evaluation, 2023
Edosa Osarogiagbon, Russ Hall, Lei Zhou, Janka Cafolla, Claire Davis
Non-destructive techniques are limited in their application which makes them difficult to use in the field. X-ray diffraction can only penetrate a few micrometres into a steel surface [37] unless high energy X-ray sources are used (e.g. synchrotron), but these have associated practical and safety restrictions. Commercial X-ray systems can be used for surface inspection of residual stresses, for example for gear manufacture. Neutron diffraction can only be carried out in dedicated facilities but can measure bulk residual stresses; this approach is more time-consuming and expensive as it takes several minutes to an hour to take a single strain measurement. Ultrasonic inspection is a non-destructive method that takes advantage of the materials’ acoustoelastic properties, the measurement is affected by microstructural features as well as any residual stresses [31,38].
Estimation of the sugar content of fruit by energy-resolved computed tomography using a material decomposition method
Published in Journal of Nuclear Science and Technology, 2021
X-ray computed tomography (CT) is an effective modality to identify tumor tissue and anomalies inside the organs of human bodies. In CT inspections at hospitals, X-rays are measured as electric current without using the energy information of X-ray photons. This measurement method is called a current measurement. X-rays are attenuated according to the linear attenuation coefficient of a material. The linear attenuation coefficient is generally greater for X-rays of lower energy according to data from the National Institute of Standards and Technology (NIST) [1]. As X-rays pass through a material, the number of low-energy X-ray photons decreases more quickly than that of high-energy X-ray photons, causing the number of high-energy X-ray photons to dominate. As a result, the averaged energy of an X-ray energy spectrum increases after passing through a material. The measured linear attenuation coefficient of the material changes as a function of the path length of the X-rays. This phenomenon is called the beam hardening effect [2].
Light Harvest: an interactive sculptural installation based on folding and mapping proteins
Published in Digital Creativity, 2018
Jiangmei Wu, Susanne Ressl, Kyle Overton
Proteins are large molecular chains with hundreds to thousands of atoms that adopt unique and perfect 3D structures through a unique self-folding process, placing chemical groups in just the right places to catalyze and build cellar functions. The process by which the atoms in a protein find their correct location to fold has fascinated structure biologists for decades, as how a protein folds and unfolds has important implications in medicine. Structural biologists use X-ray crystallography (Rupp 2010) to map the folded 3D structures of proteins through complex data collection, analysis and interpretation processes. X-ray crystallography allows the generation of very high resolution images of the molecules of life. To record high resolution X-ray diffraction images of protein crystals (Figure 1), large circular particle accelerators, synchrotrons, are used. A synchrotron emits high energy X-rays that are used to shoot protein crystals and record their diffraction images for subsequent structure determination. To study a protein folded 3-D structure, hundreds of X-ray diffraction images must be collected. A typical X-ray diffraction pattern often has thousands of spots corresponding to electron locations of atoms in a protein, and each of these spots must be measured and mapped using mathematical and computational tools to calculate a protein’s electron density map (Figure 2). These maps are then used to determine the 3-D coordinates of each atom’s positions in a given folded protein structure.