scholarly journals Data-Driven Total-Scattering Measurements by Synchrotron X-rays

2020 ◽  
Vol 40 (159) ◽  
pp. 33-36
Author(s):  
Kenichi KATO
Keyword(s):  
Data Driven ◽  
X Rays ◽  
Total Scattering ◽  
Scattering Measurements

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 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 Characterization of a Pt mirror to be used to deflect synchrotron radiation beam onto Langmuir monolayers

2015 ◽  
Vol 22 (3) ◽  
pp. 859-861 ◽  
Author(s):  
Carlos E. P. Vieira ◽  
Antonio A. M. Gasperini ◽  
Pedro P. S. Freitas ◽  
Rafael G. Oliveira ◽  
Leide P. Cavalcanti
Keyword(s):  
Liquid Surface ◽  
Langmuir Monolayers ◽  
Simple Approach ◽  
Synchrotron Radiation Beam ◽  
X Rays ◽  
Radiation Beam ◽  
Scattering Measurements ◽  
Synchrotron Light ◽  
Surface Diffraction

A homemade mirror for X-rays has been built to prepare a diffraction beamline for liquid surface diffraction and scattering measurements. This simple approach is in operation at the XRD2 bending-magnet beamline at the Brazilian Synchrotron Light Laboratory.

X-Ray Diffuse Scattering from Cobalt Precipitates in Copper

1986 ◽  
Vol 82 ◽  
Author(s):  
B. C. Larson ◽  
S. Iida ◽  
J. Z. Tischler ◽  
J. D. Lewis ◽  
G. E. Ice ◽  
...  
Keyword(s):  
Crystal Lattice ◽  
Size Distribution ◽  
Diffuse Scattering ◽  
Large Angle ◽  
Host Lattice ◽  
Internal Strain ◽  
X Rays ◽  
X Ray ◽  
Scattering Measurements

ABSTRACTLarge-angle diffuse scattering has been investigated for the purpose of studying coherent precipitates in a crystal lattice. Detailed calculations have been made of the scattering near Bragg reflections from cobalt precipitates in a copper host lattice. These calculations have been compared to x-ray diffuse scattering measurements made on aged (570°C for 17 hr.) Cu-0.95%Co crystals with x-rays of three different wavelengths at the NSLS. The results indicate that the size distribution, the concentration, and the internal strain of the precipitates can be determined from such diffuse scattering measurements.

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.

Total scattering studies of silica polymorphs: similarities in glass and disordered crystalline local structure

2000 ◽  
Vol 64 (3) ◽  
pp. 447-457 ◽  
Author(s):  
D. A. Keen ◽  
M. T. Dove
Keyword(s):  
Local Structure ◽  
Glass Structure ◽  
Quantitative Comparison ◽  
Crystalline Phases ◽  
Total Scattering ◽  
Disordered Structure ◽  
Scattering Measurements ◽  
Crystalline Forms ◽  
Short Range Correlations ◽  
Neutron Total Scattering

AbstractThe structure of amorphous silica has frequently been compared with its crystalline counterparts in an attempt to understand the glass structure beyond short-range correlations. This paper presents results from neutron total scattering measurements of several polymorphs of silica and shows how these can be used to make a direct, quantitative comparison of amorphous and crystalline forms. It is found that the glass is similar to HP-tridymite and β-cristobalite, both dynamically-disordered crystalline phases of silica, but only out to distances ∼7.5 Å, beyond which the structures diverge. This is too small to validate a microcrystallite theory of glass structure. It is the average 180° Si–O–Si linkage in these two crystalline phases which gives them the flexibility for their instantaneous disordered structure to resemble the quenched (static) glass structure.

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