Diffraction peaks restoration and extraction in energy dispersive X-ray diffraction

A full-pattern fitting algorithm for energy-dispersive X-ray diffraction is proposed, especially for high-pressure X-ray diffraction studies. The algorithm takes into account the errors in measuring the energy and the diffraction angle. A lognormal function is introduced to represent the background. All the peaks that are detectable in the diffraction spectra, including fluorescence and diffraction peaks, are considered together. Because all the data points in the spectra are used, the accuracy of the cell parameters obtained by this method is very high. This is very helpful in the analysis of the equation of state and the identification of new phases under high pressure.

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Novel Structure of MgSe in the Multimegabar Regime: Positional Parameter Determination

MRS Proceedings ◽

10.1557/proc-499-429 ◽

1997 ◽

Vol 499 ◽

Author(s):

Arthur L. Ruoff ◽

Ting Li ◽

Chandrabhas Narayana ◽

Huan Luo ◽

Raymond G. Greene

Keyword(s):

Equation Of State ◽

Structural Transformations ◽

Energy Dispersive ◽

Parameter Determination ◽

X Ray Diffraction ◽

X Ray ◽

Positional Parameter ◽

Novel Structure ◽

Diffraction Peaks ◽

Intensity Calculation

ABSTRACTThe structural transformations in the II-VI compound MgSe have been studied under pressure using energy dispersive x-ray diffraction. MgSe transforms ‘continuously’ from the rocksalt (Bl) structure to a FeSi (B28) or Au-Be structure beginning at 99 ± 8 GPa. At 202 GPa, MgSe is approaching 7-fold coordination with u = 0.0828 and w = 0.4173. The method for intensity calculation of the diffraction peaks is presented. Using the Birch equation, the equation of state to 146 GPa was determined with Bo = 62.8 + 1.6 GPa and Bo′ = 4.1.

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The suppression of fluorescence peaks in energy-dispersive X-ray diffraction

Journal of Applied Crystallography ◽

10.1107/s160057671401927x ◽

2014 ◽

Vol 47 (5) ◽

pp. 1708-1715 ◽

Cited By ~ 4

Author(s):

G. M. Hansford ◽

S. M. R. Turner ◽

D. Staab ◽

D. Vernon

Keyword(s):

Excitation Energy ◽

Preferred Orientation ◽

Energy Dispersive ◽

Source Spectrum ◽

Natural State ◽

X Ray Diffraction ◽

Scattering Angle ◽

X Ray ◽

Back Reflection ◽

Diffraction Peaks

A novel method to separate diffraction and fluorescence peaks in energy-dispersive X-ray diffraction (EDXRD) is described. By tuning the excitation energy of an X-ray tube source to just below an elemental absorption edge, the corresponding fluorescence peaks of that element are completely suppressed in the resulting spectrum. SinceBremsstrahlungphotons are present in the source spectrum up to the excitation energy, any diffraction peaks that lie at similar energies to the suppressed fluorescence peaks are uncovered. This technique is an alternative to the more usual method in EDXRD of altering the scattering angle in order to shift the energies of the diffraction peaks. However, in the back-reflection EDXRD technique [Hansford (2011).J. Appl. Cryst.44, 514–525] changing the scattering angle would lose the unique property of insensitivity to sample morphology and is therefore an unattractive option. The use of fluorescence suppression to reveal diffraction peaks is demonstrated experimentally by suppressing the Ca Kfluorescence peaks in the back-reflection EDXRD spectra of several limestones and dolomites. Three substantial benefits are derived: uncovering of diffraction peak(s) that are otherwise obscured by fluorescence; suppression of the Ca Kescape peaks; and an increase in the signal-to-background ratio. The improvement in the quality of the EDXRD spectrum allows the identification of a secondary mineral in the samples, where present. The results for a pressed-powder pellet of the geological standard JDo-1 (dolomite) show the presence of crystallite preferred orientation in this prepared sample. Preferred orientation is absent in several unprepared limestone and dolomite rock specimens, illustrating an advantage of the observation of rocks in their natural state enabled by back-reflection EDXRD.

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Formation of Cu2ZnSnS4 and Cu2ZnSnS4-CuInS2 Thin Films Investigated by In-Situ Energy Dispersive X-Ray Diffraction

MRS Proceedings ◽

10.1557/proc-1012-y03-35 ◽

2007 ◽

Vol 1012 ◽

Cited By ~ 12

Author(s):

Alfons Weber ◽

Immo Kötschau ◽

Susan Schorr ◽

Hans-Werner Schock

Keyword(s):

Thin Films ◽

Reaction Path ◽

Energy Dispersive ◽

X Ray Diffraction ◽

X Ray ◽

Diffusion Effects ◽

Cuins2 Thin Films ◽

Diffraction Peaks ◽

Poor Adhesion

AbstractChalcopyrite CuInS2 and the structurally related kesterite Cu2ZnSnS4 are known as photovoltaic absorber materials. In this study different precursor thin films of the quaternary Cu-Zn-Sn-S system (stacking: Mo/CuS/ZnS-SnS) and of the pentenary Cu-In-Zn-Sn-S system (stacking: Mo/CuIn/ZnS-SnS) were annealed in sulfur atmosphere. The predominant crystalline phases were detected by in-situ energy dispersive X-ray diffraction (EDXRD). Additionally the X-ray fluorescence signals of the film components were recorded to detect diffusion effects. For the quaternary system we found ZnS, CuS, Cu2-xS, Sn2S3 and SnS as main binary phases during annealing. The Sn2S3-SnS phase transition had a significant impact on the later formation of ternary/quaternary phases. A high diffusivity of copper can explain the little influence of the precursor stacking on the reaction path and may also be responsible for the poor adhesion of the films. For annealing temperatures above 450°C Cu2ZnSnS4 can be identified clearly by XRD. The incorporation of indium in the system leads to new diffraction peaks which can be explained by the formation of solid solutions in the system CuInS2-Cu2ZnSnS4.

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Control of the phase composition of advanced calcium phosphates using an x-ray diffractometer with a curved position-sensitive detector

Industrial laboratory Diagnostics of materials ◽

10.26896/1028-6861-2020-86-6-29-35 ◽

2020 ◽

Vol 86 (6) ◽

pp. 29-35

Author(s):

V. P. Sirotinkin ◽

O. V. Baranov ◽

A. Yu. Fedotov ◽

S. M. Barinov

Keyword(s):

Phase Composition ◽

Calcium Phosphates ◽

Position Sensitive Detector ◽

Sensitive Detector ◽

X Ray Diffraction ◽

X Ray ◽

Impurity Phases ◽

Position Sensitive ◽

Diffraction Peaks ◽

Diffraction Patterns

The results of studying the phase composition of advanced calcium phosphates Ca10(PO4)6(OH)2, β-Ca3(PO4)2, α-Ca3(PO4)2, CaHPO4 · 2H2O, Ca8(HPO4)2(PO4)4 · 5H2O using an x-ray diffractometer with a curved position-sensitive detector are presented. Optimal experimental conditions (angular positions of the x-ray tube and detector, size of the slits, exposure time) were determined with allowance for possible formation of the impurity phases during synthesis. The construction features of diffractometers with a position-sensitive detector affecting the profile characteristics of x-ray diffraction peaks are considered. The composition for calibration of the diffractometer (a mixture of sodium acetate and yttrium oxide) was determined. Theoretical x-ray diffraction patterns for corresponding calcium phosphates are constructed on the basis of the literature data. These x-ray diffraction patterns were used to determine the phase composition of the advanced calcium phosphates. The features of advanced calcium phosphates, which should be taken into account during the phase analysis, are indicated. The powder of high-temperature form of tricalcium phosphate strongly adsorbs water from the environment. A strong texture is observed on the x-ray diffraction spectra of dicalcium phosphate dihydrate. A rather specific x-ray diffraction pattern of octacalcium phosphate pentahydrate revealed the only one strong peak at small angles. In all cases, significant deviations are observed for the recorded angular positions and relative intensity of the diffraction peaks. The results of the study of experimentally obtained mixtures of calcium phosphate are presented. It is shown that the graphic comparison of experimental x-ray diffraction spectra and pre-recorded spectra of the reference calcium phosphates and possible impurity phases is the most effective method. In this case, there is no need for calibration. When using this method, the total time for analysis of one sample is no more than 10 min.

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Structural Characterization of Gallbladder Stones Using Energy Dispersive X-ray Spectroscopy and X-ray Diffraction

Combinatorial Chemistry & High Throughput Screening ◽

10.2174/1386207321666180913113803 ◽

2018 ◽

Vol 21 (7) ◽

pp. 495-500 ◽

Cited By ~ 1

Author(s):

Hassan A. Almarshad ◽

Sayed M. Badawy ◽

Abdalkarem F. Alsharari

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Energy Dispersive ◽

Spectroscopic Techniques ◽

X Ray Diffraction ◽

Major Health Problem ◽

X Ray ◽

Gallbladder Stones ◽

Pure Cholesterol ◽

Scanning Electron

Aim and Objective: Formation of the gallbladder stones is a common disease and a major health problem. The present study aimed to identify the structures of the most common types of gallbladder stones using X-ray spectroscopic techniques, which provide information about the process of stone formation. Material and Method: Phase and elemental compositions of pure cholesterol and mixed gallstones removed from gallbladders of patients were studied using energy-dispersive X-ray spectroscopy combined with scanning electron microscopy analysis and X-ray diffraction. Results: The crystal structures of gallstones which coincide with standard patterns were confirmed by X-ray diffraction. Plate-like cholesterol crystals with laminar shaped and thin layered structures were clearly observed for gallstone of pure cholesterol by scanning electron microscopy; it also revealed different morphologies from mixed cholesterol stones. Elemental analysis of pure cholesterol and mixed gallstones using energy-dispersive X-ray spectroscopy confirmed the different formation processes of the different types of gallstones. Conclusion: The method of fast and reliable X-ray spectroscopic techniques has numerous advantages over the traditional chemical analysis and other analytical techniques. The results also revealed that the X-ray spectroscopy technique is a promising technique that can aid in understanding the pathogenesis of gallstone disease.

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X-RAY DIFFRACTION AND ENERGY DISPERSIVE SPECTROSCOPY OF TERLINGUA CREEK AND ALAMITO CREEK SEDIMENTS, TRANS-PECOS REGION, TX

10.1130/abs/2018sc-310242 ◽

2018 ◽

Author(s):

J.W. Roberson ◽

◽

Olivia R. Enriquez ◽

Kevin M. Urbanczyk

Keyword(s):

Energy Dispersive Spectroscopy ◽

Energy Dispersive ◽

X Ray Diffraction ◽

X Ray

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A new technique for the study of phase transitions by means of energy dispersive x-ray diffraction. Application to polymeric samples

Journal of Macromolecular Science Part B ◽

10.1080/00222349608212381 ◽

1996 ◽

Vol 35 (2) ◽

pp. 199-213 ◽

Cited By ~ 28

Author(s):

V. Rossi Albertini ◽

L. Bencivenni ◽

R. Caminiti ◽

F. Cilloco ◽

C. Sadun

Keyword(s):

Phase Transitions ◽

Energy Dispersive ◽

New Technique ◽

X Ray Diffraction ◽

X Ray ◽

A New Technique ◽

Polymeric Samples

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Selective catalytic reduction of NO by Co-Mn based nanocatalysts

International Journal of Chemical Reactor Engineering ◽

10.1515/ijcre-2020-0240 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Vahid Zabihi ◽

Mohammad Hasan Eikani ◽

Mehdi Ardjmand ◽

Seyed Mahdi Latifi ◽

Alireza Salehirad

Keyword(s):

Selective Catalytic Reduction ◽

Catalytic Reduction ◽

Energy Dispersive ◽

Diffraction Field ◽

X Ray Diffraction ◽

X Ray ◽

Analysis Techniques ◽

Acidic Sites ◽

Temperature Window ◽

Temperature Programmed

Abstract One of the most significant aspects in selective catalytic reduction (SCR) of nitrogen oxides (NOx) is developing suitable catalysts by which the process occurs in a favorable way. At the present work SCR reaction by ammonia (NH3-SCR) was conducted using Co-Mn spinel and its composite with Fe-Mn spinel, as nanocatalysts. The nanocatalysts were fabricated through liquid routes and then their physicochemical properties such as phase composition, degree of agglomeration, particle size distribution, specific surface area and also surface acidic sites have been investigated by X-ray diffraction, Field Emission Scanning Electron Microscope, Energy-dispersive X-ray spectroscopy, energy dispersive spectroscopy mapping, Brunauer–Emmett–Teller, temperature-programmed reduction (H2-TPR) and temperature-programmed desorption of ammonia (NH3-TPD) analysis techniques. The catalytic activity tests in a temperature window of 150–400 °C and gas hourly space velocities of 10,000, 18,000 and 30,000 h−1 revealed that almost in all studied conditions, CoMn2O4/FeMn2O4 nanocomposite exhibited better performance in SCR reaction than CoMn2O4 spinel.

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