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Materials Characterization Using Advanced Synchrotron Radiation Techniques for Antimicrobial Materials
Published in Peerawatt Nunthavarawong, Sanjay Mavinkere Rangappa, Suchart Siengchin, Mathew Thoppil-Mathew, Antimicrobial and Antiviral Materials, 2022
Chatree Saiyasombat, Prae Cbirawatkul, Suittipong Wannapaiboon, Catleya Rojviriya, Siriwat Soontaranon, Nuntaporn Kamonsutthipaijit, Sirinart Chio-Srichan, Chanan Euaruksakul, Nichada Jearanaikoon
X-ray fluorescence spectroscopy (XRF) is one of the well-established characterization techniques. It is a non-destructive probe and has been used in a wide range of applications for elemental analysis. The basic principle of XRF is based on recording characteristic X-rays, so-called fluorescent X-rays, generated from the interaction between the inner shell electrons and X-rays as the materials are exposed to X-rays. Suppose the energy of incoming X-rays are higher than the binding energy of the inner shell electrons. In that case, the interaction will result in the electrons in that shell being ejected from the atom, become photoelectrons and leave holes in that energy level. The holes are then filled by cascading of electrons from higher energy levels to fill the inner shell vacancies and emitting characteristic fluorescent X-rays (Figure 7.1 [b]). By measuring the energy of the emitted characteristic X-rays, all elements in the material are qualitatively and quantitatively identified.
Research Methods of Nanostructures and Nanomaterials
Published in Zulkhair A. Mansurov, Carbon Nanomaterials in Biomedicine and the Environment, 2020
Zulkhair A. Mansurov, Nina. N. Mofa, Tatyana A. Shabanova
Back-scattered electrons (BSE) are beam electrons that are reflected from the sample by elastic scattering. BSE are often used in analytical SEM along with the spectra made from the characteristic X-rays, because the intensity of the BSE signal is strongly related to the atomic number (Z) of the specimen. BSE images can provide information about the distribution of different elements in the sample. For the same reason, BSE imaging can image colloidal gold immuno-labels of 5 or 10 nm diameter, which would otherwise be difficult or impossible to detect in secondary electron images in biological specimens. Characteristic X-rays are emitted when the electron beam removes an inner shell electron from the sample, causing a higher-energy electron to fill the shell and release energy. These characteristic X-rays are used to identify the composition and measure the abundance of elements in the sample [7].
X-Ray Methods
Published in Grinberg Nelu, Rodriguez Sonia, Ewing’s Analytical Instrumentation Handbook, Fourth Edition, 2019
When X-rays strike a sample, they can be absorbed and/or scattered through the material. Sometimes the innermost electrons can absorb all the energy and be ejected from the inner shells creating vacancies. To gain stability, electrons from outer shells can be transferred to the inner shells. This process results in the emission of X-rays that are characteristic of the material. The energy of these emitted X-rays corresponds to the difference in binding energies of the corresponding shells. As each element has a unique set of energy levels, these characteristic X-rays can be used to identify the particular element. The process of emission of characteristic X-rays from an element is termed XRF. The study of XRF is also referred to as energy dispersive X-ray spectrometry (EDX or EDS).
Review of Candidate Techniques for Material Accountancy Measurements in Electrochemical Separations Facilities
Published in Nuclear Technology, 2020
Jamie B. Coble, Steven E. Skutnik, S. Nathan Gilliam, Michael P. Cooper
X-ray fluorescence is a low-latency method based on active interrogation by an X-ray beam that can be used to determine the relative concentration of many isotopes within a UNF sample. This technique measures de-excitation X-rays emitted from ionized atoms to evaluate the relative elemental composition of the material.55 XRF relies on the fact that the electron binding energies for each shell are unique to each element. When X-rays of high enough energy to overcome the electron binding energy ionize weakly bound K-shell electrons, an electron from a higher orbital (for example, the L-shell) can drop to fill the vacancy left by the liberated electron and a characteristic X-ray is emitted whose energy is equal to the difference in the binding energies of the two electron shells.55 Because the electron binding energies are unique to each element, XRF spectra can be used to estimate elemental ratios based on the relative abundance of emitted florescence X-rays within an uncertainty of 1%. Measurement latency for XRF depends on whether the analysis is handled onsite or offsite. For onsite measurements and analysis, latency could be on the order of several hours, whereas for offsite analysis the required time could be several days.
Characterization of physical and mineralogical properties of anthracite and bituminous coal tailings
Published in International Journal of Coal Preparation and Utilization, 2021
Min Liew, Ming Xiao, Shimin Liu
The elemental and mineral compositions of coal tailings were analyzed using the following characterization techniques: scanning electron microscopy with energy dispersive spectrometry (SEM-EDS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). XRD identifies the minerals on the sample, whereas SEM-EDS and XPS identify the chemical elements. The FEI Quanta 200 SEM was utilized to bombard the sample surface with electrons, producing various characteristic X-rays. The characteristic X-rays emitted by the selected areas were then identified and quantified by EDS to analyze the elemental compositions of different minerals on the sample surface. Secondary and backscattered electron images were also generated to study the surface morphology of the coal tailings.
Study on Flotability and Surface Oxidation of Sulfide Minerals from the Tailing of an Iron-Copper Mine Using Electron Probe Microanalyzer
Published in Mineral Processing and Extractive Metallurgy Review, 2021
Yahui Zhang, Zhidong Tang, John Shirokoff
To understand the surface condition and element composition of unrecovered sulfide minerals in tailings, electron probe microanalyses were carried out. EPMA integrated with WDS can be used for the analysis of element distribution on the mineral surface, which is an efficient analytical instrument developed on the bases of electron optics and X-ray spectroscopy. During analysis, a fine focused incident electron beam strikes the sample surface, excite the characteristic X-ray of the sample element, and analyze the wavelength of the characteristic X-ray to determine the element type. Analysis of the intensity of characteristic X-rays reveals the content of the elements (Goldstein et al. 1992). In this study, WDS was employed for element analysis and scanning.