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Basic Atomic and Nuclear Physics
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Gudrun Alm Carlsson, Michael Ljungberg
The larger the positive charge of the nucleus, the stronger the electrostatic force is on the orbiting electrons. Around a nucleus with a large number of protons (high Z atomic numbers) K-shell electrons circle closer to the nucleus, and they are bounded more strongly to the nucleus than to a nucleus with a fewer number of protons (lower Z atomic number). The energy of the electrons in different shells strongly depends therefore on the atomic number of the element. The energy of the emitted K, L, M and so forth, radiation varies with the atomic number of the element. For example, the radiation from Lead (Pb) has a mean energy of 74 keV, while radiation from Oxygen (O) has a mean energy of about 0.5 keV. It is therefore possible to identify different elements by measuring the energy of the emitted characteristic x-rays. This technique, called x-ray fluorescence, has been widely used to measure different elements in human tissues by exposing various parts of the body to photons and measuring the characteristic x-rays.
Specialist Applications and Multispectral Imaging
Published in Adrian Davies, Digital Ultraviolet and Infrared Photography, 2017
From 1999 to 2008, the book was examined using various multispectral imaging techniques. The entire palimpsest was imaged in twelve spectral bands plus raking light, at a resolution of 800dpi (UV:365nm; visible light: 445, 470, 505, 530, 570, 617 and 625nm; IR: 700, 735 and 870nm; and raking light: 470 and 910nm). X-ray fluorescence was also used in some cases. On the whole, it was found that IR was not very useful in imaging the Archimedes Palimpsest because the ink used by the scribes did not contain much carbon. However, the ink did have a high iron content, and iron absorbs ultraviolet light. UV has often been used to look at faint text in medieval manuscripts, and was extremely helpful in the case of the Archimedes Palimpsest.
Unmasking the Illicit Trafficking of Nuclear and Other Radioactive Materials
Published in Michael Pöschl, Leo M. L. Nollet, Radionuclide Concentrations in Food and the Environment, 2006
Stuart Thomson, Mark Reinhard, Mike Colella, Claudio Tuniz
X-ray fluorescence is an analysis technique that is widely used for the examination of samples containing elements from sodium to plutonium. XRF is generally classified as either energy dispersive x-ray fluorescence (ED-XRF) or wavelength dispersive x-ray fluorescence (WD-XRF). An energy dispersive instrument utilizes an energy analyzing detector upon which all the resultant x-rays are focused. A wavelength dispersive instrument uses a diffraction crystal to focus x-rays of specific wavelength upon a detector. By rotating the crystal, the wavelength range is scanned. While ED-XRF systems are faster and less expensive, WD-XRF is more sensitive and has higher resolution [60].
X-ray spectrometry imaging and chemical speciation assisting to understand the toxic effects of copper oxide nanoparticles on zebrafish (Danio rerio)
Published in Nanotoxicology, 2022
Joyce Ribeiro Santos-Rasera, Rafael Giovanini de Lima, Dejane Santos Alves, Regina Teresa Rosim Monteiro, Hudson Wallace Pereira de Carvalho
Spectroscopic techniques, such as X-ray fluorescence spectroscopy (XRF) is able to identify, locate and quantify chemical elements, while X-ray absorption spectroscopy (XAS) can reveal their chemical environment, oxidation state, and symmetry. Although powerful, these techniques are not as spread in ecotoxicology as in materials science. Some of the challenges regard strategies for mapping whole organisms and detecting trace elements, this latter task has been mostly accomplished by acid digestion and the destruction of biological tissues, without actually taking a picture of the organisms (Wang 2022). Sample preparation is also challenging because it has to preserve the elements in the proper cell compartment, otherwise one may obtain misleading results. (Jin et al., 2017). The literature reports applications of isolated XRF (Mages et al. 2008) and XAS in aquatic organisms (Beauchemin et al. 2004; Misra et al. 2012; Saibu et al. 2018; Kuwabara et al. 2007). Fewer studies have combined both tools such as reported by Adams et al. (2016) and Santos-Rasera et al. (2019).
Pulmonary toxicity of inhaled nano-sized cerium oxide aerosols in Sprague–Dawley rats
Published in Nanotoxicology, 2019
Chang Guo, Sarah Robertson, Ralf J. M. Weber, Alison Buckley, James Warren, Alan Hodgson, Joshua Z. Rappoport, Konstantin Ignatyev, Kirsty Meldrum, Isabella Römer, Sameirah Macchiarulo, James Kevin Chipman, Tim Marczylo, Martin O. Leonard, Timothy W. Gant, Mark R. Viant, Rachel Smith
Synchrotron microfocus X-ray spectroscopy was carried out at the Diamond Light Source I18 Beamline (Oxfordshire, UK). Microfocus X-ray fluorescence (μ-XRF) analysis was undertaken to provide information on the spatial distribution of elements of interest for a number of lung sections. For identified areas of high cerium concentration, X-ray absorption near-edge structure (XANES) spectrometry of the Ce LIII-edge was carried out to investigate chemical speciation (e.g. oxidation state). The spectra produced were compared with those for samples of some cerium compounds: Ce2(CO3)3, Ce(OH)4 (Sigma-Aldrich, St. Louis, MO), and CeO2 (Acros Organics, Morris, NJ), and a sample of the CeO2NPs. Further details are described in the Supplementary information.
Characterization, kinetics and thermodynamics of biosynthesized uranium nanoparticles (UNPs)
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Mervate Aly Abostate, Youssry Saleh, Hamed Mira, Maysa Amin, Maha Al Kazindar, Basma Mahmoud Ahmed
X-ray fluorescence technique (XRF) was used to determine the trace element contents using PHILIPS X unique – II spectrophotometer with automatic sample changer PW 1510 (30 positions), Holland. This instrument is connected to a computer system using X-40 program for spectrometry. The trace elements concentrations are calculated from the program's calibration curves which were set up according to international reference materials, (standards), as NIM-G, G-2, GSP-1, AGV-1, JB-1 and NIM-D..