scholarly journals Defect-Distribution Simulation of Crystalline Oxide by Neutron and Synchrotron X-Ray Total Scattering Measurements

2017 ◽  
Vol 64 (9) ◽  
pp. 489-494
Author(s):  
Naoto KITAMURA ◽  
Yasushi IDEMOTO
Keyword(s):  
Defect Distribution ◽  
Total Scattering ◽  
X Ray ◽  
Crystalline Oxide ◽  
Scattering Measurements

scholarly journals Calculation of total scattering from a crystalline structural model based on experimental optics parameters

2020 ◽  
Vol 53 (3) ◽  
pp. 671-678 ◽  
Author(s):  
Satoshi Hiroi ◽  
Koji Ohara ◽  
Satoru Ohuchi ◽  
Yukihiro Umetani ◽  
Takashi Kozaki ◽  
...  
Keyword(s):  
Amorphous Materials ◽  
Structural Model ◽  
Direct Calculation ◽  
Structural Disorder ◽  
Optical Parameters ◽  
Diffraction Profile ◽  
Total Scattering ◽  
X Ray ◽  
Scattering Measurements ◽  
Total Structure

Total scattering measurements enable understanding of the structural disorder in crystalline materials by Fourier transformation of the total structure factor, S(Q), where Q is the magnitude of the scattering vector. In this work, the direct calculation of total scattering from a crystalline structural model is proposed. To calculate the total scattering intensity, a suitable Q-broadening function for the diffraction profile is needed because the intensity and the width depend on the optical parameters of the diffraction apparatus, such as the X-ray energy resolution and divergence, and the intrinsic parameters. X-ray total scattering measurements for CeO2 powder were performed at beamline BL04B2 of the SPring-8 synchrotron radiation facility in Japan for comparison with the calculated S(Q) under various optical conditions. The evaluated Q-broadening function was comparable to the full width at half-maximum of the Bragg peaks in the experimental total scattering pattern. The proposed calculation method correctly accounts for parameters with Q dependence such as the atomic form factor and resolution function, enables estimation of the total scattering factor, and facilitates determination of the reduced pair distribution function for both crystalline and amorphous materials.

scholarly journals High-Precision X-ray Total Scattering Measurements Using a High-Accuracy Detector System

2021 ◽  
Vol 7 (1) ◽  
pp. 2
Author(s):  
Kenichi Kato ◽  
Kazuya Shigeta
Keyword(s):  
High Precision ◽  
Dynamic Range ◽  
Atomic Displacement ◽  
High Accuracy ◽  
Detector System ◽  
Scattering Method ◽  
X Rays ◽  
Total Scattering ◽  
X Ray ◽  
Scattering Measurements

The total scattering method, which is based on measurements of both Bragg and diffuse scattering on an equal basis, has been still challenging even by means of synchrotron X-rays. This is because such measurements require a wide coverage in scattering vector Q, high Q resolution, and a wide dynamic range for X-ray detectors. There is a trade-off relationship between the coverage and resolution in Q, whereas the dynamic range is defined by differences in X-ray response between detector channels (X-ray response non-uniformity: XRNU). XRNU is one of the systematic errors for individual channels, while it appears to be a random error for different channels. In the present study, taking advantage of the randomness, the true sensitivity for each channel has been statistically estimated. Results indicate that the dynamic range of microstrip modules (MYTHEN, Dectris, Baden-Daettwil, Switzerland), which have been assembled for a total scattering measurement system (OHGI), has been successfully restored from 104 to 106. Furthermore, the correction algorithm has been optimized to increase time efficiencies. As a result, the correcting time has been reduced from half a day to half an hour, which enables on-demand correction for XRNU according to experimental settings. High-precision X-ray total scattering measurements, which has been achieved by a high-accuracy detector system, have demonstrated valence density studies from powder and PDF studies for atomic displacement parameters.

scholarly journals Exploring the origins of crystallisation kinetics in hierarchical materials using in situ X-ray diffraction and pair distribution function analysis

2020 ◽  
Vol 22 (34) ◽  
pp. 18860-18867 ◽  
Author(s):  
Matthew E. Potter ◽  
Mark E. Light ◽  
Daniel J. M. Irving ◽  
Alice E. Oakley ◽  
Stephanie Chapman ◽  
...  
Keyword(s):  
Distribution Function ◽  
Pair Distribution Function ◽  
Function Analysis ◽  
X Ray Diffraction ◽  
Crystallisation Kinetics ◽  
Total Scattering ◽  
Hierarchically Porous ◽  
X Ray ◽  
Scattering Measurements

Novel in situ synchrotron total scattering measurements probe the assembly of primary building units into templated hierarchically porous aluminophosphate catalysts, providing unique insights to understanding crystallisation kinetics.

Dimensions de micelles mixtes de p-alkylbenzènesulfonates par diffusion central des rayons X

1977 ◽  
Vol 10 (1) ◽  
pp. 37-44 ◽  
Author(s):  
C. Cabos ◽  
P. Delord ◽  
J. Rouviere
Keyword(s):  
Small Angle ◽  
Small Angle Scattering ◽  
Micellar Solutions ◽  
Probable Structure ◽  
X Ray ◽  
Absolute Scale ◽  
Angle Scattering ◽  
Scattering Measurements ◽  
Two Component ◽  
Most Probable Structure

The structure of micellar solutions is determined from X-ray small-angle scattering measurements on an absolute scale. The most probable structure is chosen by comparison with spherical cylindrical and lamellar models. This method is applied to two-component micelles and it is possible to follow the variation of micellar dimensions when the concentration of each component is varying.

X-Ray and Raman Studies of Interlayer Mixing in SimGem Superlattices

1991 ◽  
Vol 220 ◽  
Author(s):  
R. C. Bowman ◽  
P. M. Adams ◽  
S. J. Chang ◽  
V. Arbet-Engels ◽  
K. L. Wang
Keyword(s):  
Activation Energy ◽  
Raman Scattering ◽  
Vacancy Mechanism ◽  
Strained Si ◽  
X Ray ◽  
Scattering Measurements ◽  
Intensity Changes ◽  
Interface Mixing ◽  
Interdiffusion Coefficients

ABSTRACTInterface mixing between the Ge and Si layers in symmetrically strained SimGem superlattices occurs during post growth thermal anneals. Interdiffusion coefficients were obtained from intensity changes in the low angle superlattice x-ray satellites on samples with nominal periodicities between 1.4nm and 5.6nm. A common activation energy of 3.0±0.1 eV was found. The bulk interdiffusion coefficients for SimGem were derived since measurements were made on samples with different layer thicknesses. Intermixing appears to occur by diffusion of Si atoms into the Ge layers via a vacancy mechanism. Raman scattering measurements support this process as well as the formation of Si1−xGex, alloy layers during the anneals.

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