A high-rate gaseous area detector for x-ray diffraction applications

2004 ◽  
Author(s):  
David M. Khazins ◽  
Bruce L. Becker ◽  
Bob B. He ◽  
Yacouba Diawara ◽  
Roger D. Durst ◽  
...  
Keyword(s):  
High Rate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Area Detector

Polyhedral characteristics of the cosalite-type crystal structures

2019 ◽  
Vol 57 (5) ◽  
pp. 647-662
Author(s):  
Sabina Kovač ◽  
Predrag Dabić ◽  
Aleksandar Kremenović ◽  
Aleksandar Pačevski ◽  
Ljiiljana Karanović ◽  
...  
Keyword(s):  
Crystal Data ◽  
Chemical Formula ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Area Detector ◽  
Octahedral Sites ◽  
Distorted Octahedral ◽  
Cation Substitutions ◽  
Type Crystal

Abstract The crystal structure of cosalite from the Trepča orefield was refined in the orthorhombic space group Pnma [a = 23.7878 (9), b = 4.0566 (3), c = 19.1026 (8) Å, V = 1843.35 (17) Å3, Z = 2] from single-crystal data (MoKα X-ray diffraction, CCD area detector) to the conventional R1 factor 0.031 for 1516 unique reflections with I > 2σ(I). The chemical formula (Cu0.15Ag0.24)+(Fe0.19Pb7.20)2+(Bi7.06Sb1.06)3+S20, calculated on the basis of 20 S atoms per formula unit, was determined by WDX. The unit cell contains 18 + 2 symmetrically nonequivalent atomic sites: 10 occupied by S; two by pure Pb (Pb3 and Pb4); one by pure Bi (Bi1); two by a combination of Bi and small amounts of Sb (Bi2/Sb2, Bi4/Sb3); two by Pb and Bi, and in one of these also by a small amount of Ag [Me1 = Pb2 >> Bi5 > Ag1, Me3 = Pb1 >> Bi3]; and finally one site, Me2 (Bi6 >> □), is partly occupied by Bi and partly split into an additional two adjacent trigonal planar “interstitial positions”, Cu1 and Cu2, where small amounts of Cu, Ag, and Fe can be situated. All atoms are at 4c special positions at y = 0.25 or 0.75. The structure consists of slightly to moderately distorted MeS6 octahedra sharing edges, bicapped trigonal PbS8 coordination prisms, and fairly distorted Cu1S6 and Cu2S4 polyhedra. The effects of the cation substitutions, bond valence sums, and the polyhedral characteristics are compared with other published cosalite-type structures. Among known cosalite-type structures, the largest volume contraction is shown by sample 4 (Altenberg) and involves the replacement of large cations (Bi3+ and Pb2+) by the smaller Sb3+, as well as Cu+ and Ag+. These replacements are reflected in the variations of individual Me–S bond distances, which are accompanied by variations in average Me–S distances. The degree of polyhedral distortion, Δ, progressively increases for the four Bi-hosting sites of nine cosalite-type structures: Me2 < Bi2 < Bi1 < Bi4. The Bi4 and Me3 are the most and the Me1 and Me2 are the least distorted octahedral sites of the nine cosalite-type structures.

Multipurpose diffractometer for in situ X-ray crystallography of functional materials

2021 ◽  
Vol 54 (3) ◽  
Author(s):  
Semën Gorfman ◽  
David Spirito ◽  
Netanela Cohen ◽  
Peter Siffalovic ◽  
Peter Nadazdy ◽  
...  
Keyword(s):  
Electric Field ◽  
Materials Science ◽  
Functional Materials ◽  
X Ray Diffraction ◽  
Reciprocal Space Mapping ◽  
X Ray ◽  
X Ray Crystallography ◽  
Area Detector ◽  
Characterization Of Materials

Laboratory X-ray diffractometers play a crucial role in X-ray crystallography and materials science. Such instruments still vastly outnumber synchrotron facilities and are responsible for most of the X-ray characterization of materials around the world. The efforts to enhance the design and performance of in-house X-ray diffraction instruments benefit a broad research community. Here, the realization of a custom-built multipurpose four-circle diffractometer in the laboratory for X-ray crystallography of functional materials at Tel Aviv University, Israel, is reported. The instrument is equipped with a microfocus Cu-based X-ray source, collimating X-ray optics, four-bounce monochromator, four-circle goniometer, large (PILATUS3 R 1M) pixel area detector, analyser crystal and scintillating counter. It is suitable for a broad range of tasks in X-ray crystallography/structure analysis and materials science. All the relevant X-ray beam parameters (total flux, flux density, beam divergence, monochromaticity) are reported and several applications such as determination of the crystal orientation matrix and high-resolution reciprocal-space mapping are demonstrated. The diffractometer is suitable for measuring X-ray diffraction in situ under an external electric field, as demonstrated by the measurement of electric-field-dependent rocking curves of a quartz single crystal. The diffractometer can be used as an independent research instrument, but also as a training platform and for preparation for synchrotron experiments.

scholarly journals Visualizing mineralization processes and fossil anatomy using synchronous synchrotron X-ray fluorescence and X-ray diffraction mapping

2020 ◽  
Vol 17 (169) ◽  
pp. 20200216 ◽  
Author(s):  
Pierre Gueriau ◽  
Solenn Réguer ◽  
Nicolas Leclercq ◽  
Camila Cupello ◽  
Paulo M. Brito ◽  
...  
Keyword(s):  
Cross Sections ◽  
Soft Tissues ◽  
Local Strain ◽  
Phase Identification ◽  
X Ray Diffraction ◽  
X Ray ◽  
Area Detector ◽  
Transmission Geometry ◽  
Mineralization Processes ◽  
Elemental Data

Fossils, including those that occasionally preserve decay-prone soft tissues, are mostly made of minerals. Accessing their chemical composition provides unique insight into their past biology and/or the mechanisms by which they preserve, leading to a series of developments in chemical and elemental imaging. However, the mineral composition of fossils, particularly where soft tissues are preserved, is often only inferred indirectly from elemental data, while X-ray diffraction that specifically provides phase identification received little attention. Here, we show the use of synchrotron radiation to generate not only X-ray fluorescence elemental maps of a fossil, but also mineralogical maps in transmission geometry using a two-dimensional area detector placed behind the fossil. This innovative approach was applied to millimetre-thick cross-sections prepared through three-dimensionally preserved fossils, as well as to compressed fossils. It identifies and maps mineral phases and their distribution at the microscale over centimetre-sized areas, benefitting from the elemental information collected synchronously, and further informs on texture (preferential orientation), crystallite size and local strain. Probing such crystallographic information is instrumental in defining mineralization sequences, reconstructing the fossilization environment and constraining preservation biases. Similarly, this approach could potentially provide new knowledge on other (bio)mineralization processes in environmental sciences. We also illustrate that mineralogical contrasts between fossil tissues and/or the encasing sedimentary matrix can be used to visualize hidden anatomies in fossils.

scholarly journals X-ray Diffraction Investigation of Stainless Steel—Nitrogen Thin Films Deposited Using Reactive Sputter Deposition

Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 984
Author(s):  
Faisal I. Alresheedi ◽  
James E. Krzanowski
Keyword(s):  
Thin Films ◽  
Stainless Steel ◽  
Substrate Temperature ◽  
Peak Shift ◽  
304 Stainless Steel ◽  
Tetragonal Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Area Detector ◽  
Calculated Parameter

An X-ray diffraction investigation was carried out on nitrogen-containing 304 stainless steel thin films deposited by reactive rf magnetron sputtering over a range of substrate temperature and bias levels. The resulting films contained between ~28 and 32 at.% nitrogen. X-ray analysis was carried out using both the standard Bragg-Brentano method as well as area-detector diffractometry analysis. The extent of the diffraction anomaly ((002) peak shift) was determined using a calculated parameter, denoted RB, which is based on the (111) and (002) peak positions. The normal value for RB for FCC-based structures is 0.75 but increases as the (002) peak is anomalously displaced closer to the (111) peak. In this study, the RB values for the deposited films were found to increase with substrate bias but decrease with substrate temperature (but still always >0.75). Using area detector diffractometry, we were able to measure d111/d002 values for similarly oriented grains within the films, and using these values calculate c/a ratios based on a tetragonal-structure model. These results allowed prediction of the (002)/(200) peak split for tetragonal structures. Despite predicting a reasonably accessible split (~0.6°–2.9°–2θ), no peak splitting observed, negating the tetragonal-structure hypothesis. Based on the effects of film bias/temperature on RB values, a defect-based hypothesis is more viable as an explanation for the diffraction anomaly.

On the calibration of high-energy X-ray diffraction setups. I. Assessing tilt and spatial distortion of the area detector

2014 ◽  
Vol 47 (3) ◽  
pp. 1042-1053 ◽  
Author(s):  
Andras Borbely ◽  
Loic Renversade ◽  
Peter Kenesei ◽  
Jonathan Wright
Keyword(s):  
Rotation Axis ◽  
Strain Tensor ◽  
Calibration Procedure ◽  
High Energy ◽  
European Synchrotron Radiation Facility ◽  
Data Sets ◽  
X Ray Diffraction ◽  
Spatial Distortion ◽  
X Ray ◽  
Area Detector

The geometry of high-energy X-ray diffraction setups using an area detector and a rotation axis is analysed. The present paper (part 1) describes the methodology for determining continuously varying spatial distortions and tilt of the area detector based on the reference diffraction rings of a certified powder. Analytical expressions describing the degeneration of Debye rings into ellipses are presented and a robust calibration procedure is introduced. It is emphasized that accurate detector calibration requires the introduction of spatial distortion into the equation describing the tilt. The method is applied to data sets measured at the Advanced Photon Source and at the European Synchrotron Radiation Facility using detectors with different physical characteristics, the GE 41RT flat-panel and the FReLoN4M detector, respectively. The spatial distortion of the detectors is compared with regard to their use in structural and strain tensor analysis, a subject treated in part 2 of the calibration work [Borbély, Renversade & Kenesei (2014).J. Appl. Cryst.Submitted].

Irreversible phase transition between LiFePO4 and FePO4 during high-rate charge-discharge reaction by operando X-ray diffraction

2016 ◽  
Vol 309 ◽  
pp. 122-126 ◽  
Author(s):  
Ikuma Takahashi ◽  
Takuya Mori ◽  
Takahiro Yoshinari ◽  
Yuki Orikasa ◽  
Yukinori Koyama ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Rate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Charge Discharge ◽  
Discharge Reaction

scholarly journals Quantification of Thin Film Crystallographic Orientation Using X-ray Diffraction with an Area Detector

Langmuir ◽  
2010 ◽  
Vol 26 (11) ◽  
pp. 9146-9151 ◽  
Author(s):  
Jessy L. Baker ◽  
Leslie H. Jimison ◽  
Stefan Mannsfeld ◽  
Steven Volkman ◽  
Shong Yin ◽  
...  
Keyword(s):  
Thin Film ◽  
Crystallographic Orientation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Area Detector

scholarly journals EXCALIBUR: a small-pixel photon counting area detector for coherent X-ray diffraction - Front-end design, fabrication and characterisation

2013 ◽  
Vol 425 (6) ◽  
pp. 062003 ◽  
Author(s):  
J Marchal ◽  
I Horswell ◽  
B Willis ◽  
R Plackett ◽  
E N Gimenez ◽  
...  
Keyword(s):  
Photon Counting ◽  
X Ray Diffraction ◽  
X Ray ◽  
Area Detector ◽  
Front End ◽  
Small Pixel

Investigation of Phase Transitions in Stacked GeTe/SnTe and Ge2Se3/SnTe Chalcogenide Films

2011 ◽  
Vol 687 ◽  
pp. 677-683 ◽  
Author(s):  
Fei Ming Bai ◽  
Huai Wu Zhang ◽  
Surendra Gupta ◽  
Santosh Kurinec
Keyword(s):  
Phase Transition ◽  
Solid Solution ◽  
Phase Transitions ◽  
Phase Change Memory ◽  
Thin Layers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Area Detector ◽  
Memory Applications ◽  
Change Memory

Phase transitions in stacked GeTe/SnTe and Ge2Se3/SnTe thin layers for potential phase-change memory applications have been investigated by X-ray diffraction using an area detector system and by scanning electron microscopy. The as-deposited underlying GeTe or Ge2Se3 layer is amorphous, whereas the top SnTe layer is crystalline. In GeTe/SnTe stack, the crystallization of GeTe phase occurs near 170°C, and upon further heating, GeTe phase disappears, followed by the formation of rocksalt-structured GexSn1-xTe solid solution. In Ge2Se3/SnTe stack, the phase transition starts with the separation of SnSe phase due to the migration of Sn ions into the Ge2Se3 layer. The migration of Sn ions and the formation of SnSe are believed to facilitate the crystallization of Ge2Se3 solid solution at ~360°C, which is much lower than the crystallization temperature of Ge2Se3, therefore consuming less power during the phase transition.

scholarly journals X-Ray Diffraction Study of Amorphous CeFe2H3 and GdFe2H3 Alloys Produced by Hydrogenation

1987 ◽  
Vol 42 (6) ◽  
pp. 582-586 ◽  
Author(s):  
E. Matsubara ◽  
Y. Ohzora ◽  
Y. Waseda ◽  
K. Aoki ◽  
K. Fukamichi ◽  
...  
Keyword(s):  
Diffraction Study ◽  
Structural Features ◽  
High Rate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dc Sputtering

The structure of amorphous CeFe2H3 and GdFe2H3 alloys produced by hydrogenation is investigated and compared with that of amorphous CeFe2 and GdFe2 produced by high-rate DC sputtering. Distinct different structural features, characterized by an almost resolved first peak of the RDF of the former were found.

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