X-Ray Absorption Coefficient Behavior Depending on Disposition of Diffraction Vector and Temperature Gradient Vector

The behavior of the interference absorption coefficient of X-rays in Laue geometry depending upon the disposition of diffraction vector and temperature gradient vector in the perpendicular direction to the reflecting atomic planes family was experimentally studied. The study was carried out for the different thicknesses of quartz single crystal for atomic planes. It was shown that in the case of anti-parallel disposition of the diffraction vector and temperature gradient vector the absorption coefficient of X-rays sharply decreases with the increase of temperature gradient and in the case of the parallel disposition of the diffraction vector and the temperature gradient vector the absorption coefficient firstly increases and then decreases. The theoretical calculation corresponding to the experiment conditions have been done. The physical explanation of the obtained experimental results has been made. The obtained results are in good correspondence with the experiment.

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Pistachio deterioration detected by X-ray absorption

Czech Journal of Food Sciences ◽

10.17221/101/2012-cjfs ◽

2013 ◽

Vol 31 (No. 2) ◽

pp. 126-131

Author(s):

A. Proshlyakov ◽

S. Yanniotis ◽

J. Blahovec

Keyword(s):

Absorption Coefficient ◽

X Rays ◽

X Ray ◽

Moisture Contents ◽

Cell Dimensions ◽

X Ray Absorption

The measurement of the absorption coefficient of X-rays in healthy and fungus infected pistachio kernels was the main objective of this work aimed at detecting the potential injury by insects and/or fungi in the kernel. It was found that the absorption coefficient in the injured parts is about half of that in the healthy parts. The absorption coefficient is also affected by the position in the kernel due to the variations in cell dimensions and the oil and moisture contents in the kernels.  

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Focusing of hard X-ray beams in quartz crystal under the temperature gradient

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314088627 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C1137-C1137

Author(s):

Vahan Kocharyan ◽

Sargis Khlopuzyan ◽

Poghos Grigoryan ◽

Edik Baghdasaryan ◽

Ruben Amiraghyan

Keyword(s):

Temperature Gradient ◽

Plane Wave ◽

Quartz Crystal ◽

Spectral Width ◽

X Rays ◽

Ultrasonic Vibrations ◽

Diffraction Vector ◽

Wave Fronts ◽

X Ray ◽

Focus Point

The research of the focusing and defocusing of the diffracted X-rays with different wave fronts in crystals under the influences of the temperature gradient and the ultrasonic vibrations is given in the works [1,2]. This work is dedicated experimentally investigation of Laue diffraction of the hard X-rays in quartz single crystals under the influence of the temperature gradient. It is shown that the reflected beams under the influence of the temperature gradient are focused. When the vector of the temperature gradient is anti parallel to the diffraction vector, in accordance to the increasing value of the temperature gradient the focus point continuously approaches the crystal. When the vector of the temperature gradient is parallel to the diffraction vector, in accordance with the increasing value of the temperature gradient the focus point continuously distances itself from the crystal, and at a certain value of the temperature gradient it becomes a plane wave. Parallel to the further increasing of the temperature gradient we see an imaginary focus, which continuously approaches the entry surface of the crystal. It is shown that by using a thicker single crystal it is possible to focus and pump a larger angular and spectral width of X-rays in the direction of diffraction.

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X-Ray absorption edge elemental imaging of B. thuringienis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100153038 ◽

1989 ◽

Vol 47 ◽

pp. 212-213

Author(s):

R. L. Stears

Keyword(s):

Absorption Edge ◽

Elemental Distribution ◽

X Rays ◽

Differential Absorption ◽

Synchrotron Source ◽

High Brightness ◽

X Ray ◽

Elemental Imaging ◽

Cellular Integrity ◽

X Ray Absorption

Because of the nature of the bacterial endospore, little work has been done on analyzing their elemental distribution and composition in the intact, living, hydrated state. The majority of the qualitative analysis entailed intensive disruption and processing of the endospores, which effects their cellular integrity and composition.Absorption edge imaging permits elemental analysis of hydrated, unstained specimens at high resolution. By taking advantage of differential absorption of x-ray photons in regions of varying elemental composition, and using a high brightness, tuneable synchrotron source to obtain monochromatic x-rays, contact x-ray micrographs can be made of unfixed, intact endospores that reveal sites of elemental localization. This study presents new data demonstrating the application of x-ray absorption edge imaging to produce elemental information about nitrogen (N) and calcium (Ca) localization using Bacillus thuringiensis as the test specimen.

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Al-driven peculiarities of local coordination and magnetic properties in single-phase Alx-CrFeCoNi high-entropy alloys

Nano Research ◽

10.1007/s12274-021-3704-5 ◽

2021 ◽

Author(s):

Alevtina Smekhova ◽

Alexei Kuzmin ◽

Konrad Siemensmeyer ◽

Chen Luo ◽

Kai Chen ◽

...

Keyword(s):

Magnetic Properties ◽

Single Phase ◽

Magnetic Circular Dichroism ◽

Surface Region ◽

Face Centered Cubic ◽

X Rays ◽

X Ray ◽

High Entropy ◽

X Ray Absorption ◽

Absorption Edges

AbstractModern design of superior multi-functional alloys composed of several principal components requires in-depth studies of their local structure for developing desired macroscopic properties. Herein, peculiarities of atomic arrangements on the local scale and electronic states of constituent elements in the single-phase face-centered cubic (fcc)- and body-centered cubic (bcc)-structured high-entropy Alx-CrFeCoNi alloys (x = 0.3 and 3, respectively) are explored by element-specific X-ray absorption spectroscopy in hard and soft X-ray energy ranges. Simulations based on the reverse Monte Carlo approach allow to perform a simultaneous fit of extended X-ray absorption fine structure spectra recorded at K absorption edges of each 3d constituent and to reconstruct the local environment within the first coordination shells of absorbers with high precision. The revealed unimodal and bimodal distributions of all five elements are in agreement with structure-dependent magnetic properties of studied alloys probed by magnetometry. A degree of surface atoms oxidation uncovered by soft X-rays suggests different kinetics of oxide formation for each type of constituents and has to be taken into account. X-ray magnetic circular dichroism technique employed at L2.3 absorption edges of transition metals demonstrates reduced magnetic moments of 3d metal constituents in the sub-surface region of in situ cleaned fcc-structured Al0.3-CrFeCoNi compared to their bulk values. Extended to nanostructured versions of multicomponent alloys, such studies would bring new insights related to effects of high entropy mixing on low dimensions.

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Synchrotron X-ray induced acoustic imaging

Scientific Reports ◽

10.1038/s41598-021-83604-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Seongwook Choi ◽

Eun-Yeong Park ◽

Sinyoung Park ◽

Jong Hyun Kim ◽

Chulhong Kim

Keyword(s):

Acoustic Imaging ◽

Signal Frequency ◽

X Rays ◽

Repetition Period ◽

Linear Accelerators ◽

X Ray ◽

X Ray Computed ◽

Medical Linear Accelerators ◽

Ionizing Radiation Exposure ◽

X Ray Absorption

AbstractX-ray induced acoustic imaging (XAI) is an emerging biomedical imaging technique that can visualize X-ray absorption contrast at ultrasound resolution with less ionizing radiation exposure than conventional X-ray computed tomography. So far, medical linear accelerators or industrial portable X-ray tubes have been explored as X-ray excitation sources for XAI. Here, we demonstrate the first feasible synchrotron XAI (sXAI). The synchrotron generates X-rays, with a dominant energy of 4 to 30 keV, a pulse-width of 30 ps, a pulse-repetition period of 2 ns, and a bunch-repetition period of 940 ns. The X-ray induced acoustic (XA) signals are processed in the Fourier domain by matching the signal frequency with the bunch-repetition frequency. We successfully obtained two-dimensional XA images of various lead targets. This novel sXAI tool could complement conventional synchrotron applications.

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Semi-automated protein crystal mounting device for the sulfur single-wavelength anomalous diffraction method

Journal of Applied Crystallography ◽

10.1107/s0021889809054272 ◽

2010 ◽

Vol 43 (2) ◽

pp. 341-346 ◽

Cited By ~ 14

Author(s):

Yu Kitago ◽

Nobuhisa Watanabe ◽

Isao Tanaka

Keyword(s):

Diffraction Method ◽

Systematic Errors ◽

Protein Crystal ◽

X Rays ◽

Anomalous Diffraction ◽

X Ray ◽

Frozen Solution ◽

Custom Made ◽

Protein Molecules ◽

X Ray Absorption

Use of longer-wavelength X-rays has advantages for the detection of small anomalous signals from light atoms, such as sulfur, in protein molecules. However, the accuracy of the measured diffraction data decreases at longer wavelengths because of the greater X-ray absorption. The capillary-top mounting method (formerly the loopless mounting method) makes it possible to eliminate frozen solution around the protein crystal and reduces systematic errors in the evaluation of small anomalous differences. However, use of this method requires custom-made tools and a large amount of skill. Here, the development of a device that can freeze the protein crystal semi-automatically using the capillary-top mounting method is described. This device can pick up the protein crystal from the crystallization drop using a micro-manipulator, and further procedures, such as withdrawal of the solution around the crystal by suction and subsequent flash freezing of the protein crystal, are carried out automatically. This device makes it easy for structural biologists to use the capillary-top mounting method for sulfur single-wavelength anomalous diffraction phasing using longer-wavelength X-rays.

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Anisotropy of X-ray Absorption Cross Section in CeCoGe3 Single Crystal

Crystals ◽

10.3390/cryst11050544 ◽

2021 ◽

Vol 11 (5) ◽

pp. 544

Author(s):

Andrei Rogalev ◽

Fabrice Wilhelm ◽

Elena Ovchinnikova ◽

Aydar Enikeev ◽

Roman Bakonin ◽

...

Keyword(s):

Cross Section ◽

Absorption Cross Section ◽

Linear Dichroism ◽

X Rays ◽

Absorption Cross ◽

X Ray ◽

Measured Absorption ◽

Linearly Polarized ◽

X Ray Absorption ◽

Absorption Edges

Absorption spectra of two orthogonal linearly polarized x-rays in a single CeCoGe3 crystal were measured at the ID12 beamline of the ESRF for the energies near the K-edges of Ge, Co and near the L23 edges of Ce. The X-ray natural linear dichroism (XNLD) was revealed in the vicinity of all the absorption edges, which indicates a splitting of electronic states in a crystalline field. Mathematical modelling in comparison with experimental data allowed the isotropic and anisotropic parts of atomic absorption cross section in CeCoGe3 to be determined near all measured absorption edges. The calculations also show that the “average” anisotropy of the cross section close to the Ge K-edge revealed in the experiment is less than the partial anisotropic contributions corresponding to Ge atoms in two different Wyckoff positions.

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Synthesis and Characterisation of Thin Films of Bismuth Triiodide for Semiconductor Radiation Detectors

Conference Papers in Science ◽

10.1155/2014/370436 ◽

2014 ◽

Vol 2014 ◽

pp. 1-3 ◽

Cited By ~ 6

Author(s):

Alka Garg ◽

Monika Tomar ◽

Vinay Gupta

Keyword(s):

Thin Films ◽

Absorption Coefficient ◽

Room Temperature ◽

Active Material ◽

Visible Region ◽

Radiation Detectors ◽

Radiation Absorption ◽

X Rays ◽

X Ray ◽

Bismuth Iodide

Bismuth iodide is a potentially active material for room temperature radiation detector, as it is well reported in the literature that it has both wide energy band gap and high atomic absorption coefficient. Crystalline films of high atomic number and high radiation absorption coefficient can absorb the X-rays and convert them directly into electrical charges which can be read by imaging devices. Therefore, it was proposed to grow thin films of Bismuth iodide on glass substrate using thermal evaporation technique in vacuum to avoid the inclusion of impurities in the films. The structural studies of the films were carried out using XRD and optical absorption measurement was carried out in the UV/VIS region using spectrophotometer. All Bismuth iodide films grown at room temperature are polycrystalline and show X-ray diffraction peaks at angles reported in research papers. The optical transmission spectra of BiI3 films show a high transmission of about 80% in visible region with a sharp fall near the fundamental absorption at 650 nm. Resistivity of the as-grown film was found to be around 1012 ohm-cm suitable value for X-ray detection application. Films were subjected to scanning electron microscopy to study the growth features of both as-grown and annealed films.

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A high-energy triple-axis X-ray diffractometer for the study of the structure of bulk crystals

Journal of Applied Crystallography ◽

10.1107/s0021889804023805 ◽

2004 ◽

Vol 37 (6) ◽

pp. 901-910 ◽

Cited By ~ 6

Author(s):

C. Seitz ◽

M. Weisser ◽

M. Gomm ◽

R. Hock ◽

A. Magerl

Keyword(s):

High Energy ◽

X Rays ◽

Bulk Crystals ◽

X Ray Diffraction ◽

X Ray ◽

Peak Intensity ◽

High Penetration ◽

Massive Sample ◽

Laue Geometry ◽

The Ideal

A triple-axis diffractometer for high-energy X-ray diffraction is described. A 450 kV/4.5 kW stationary tungsten X-ray tube serves as the X-ray source. Normally, 220 reflections of thermally annealed Czochralski Si are employed for the monochromator and analyser. Their integrated reflectivity is about ten times higher than the ideal crystal value. With the same material as the sample, and working with the WKα line at 60 keV in symmetric Laue geometry for all axes, the full width at half-maximum (FWHM) values for the longitudinal and transversal resolution are 2.5 × 10−3and 1.1 × 10−4for ΔQ/Q, respectively, and the peak intensity for a non-dispersive setting is 3000 counts s−1. In particular, for a double-axis mode, an energy well above 100 keV from theBremsstrahlungspectrum can be used readily. High-energy X-rays are distinguished by a high penetration power and materials of several centimetre thickness can be analysed. The feasibility of performing experiments with massive sample environments is demonstrated.

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