Correction of specimen absorption in X-ray diffuse scattering experiments with area-detector systems

2000 ◽  
Vol 33 (1) ◽  
pp. 35-48 ◽  
Author(s):  
Stefan Scheidegger ◽  
Michael Alexander Estermann ◽  
Walter Steurer
Keyword(s):  
Diffuse Scattering ◽  
Amorphous Materials ◽  
Routine Data ◽  
Scattering Data ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Area Detector ◽  
Absorption Correction ◽  
Transmission Factors

Methods for correcting specimen absorption in X-ray diffraction experiments, dedicated to two-dimensional area-detector systems and broad diffuse scattering phenomena, are implemented and tested. The respective transmission factors, in relation to the crystal or specimen shape, are applied to the intensity of every pixel of the two-dimensional detector. The pixel-wise approach allows for a fully quantitative treatment of continuous diffraction information, such as disorder diffuse scattering or scattering from amorphous materials, which is collected with a two-dimensional detector system. This is in contrast to routine data reduction, where the transmission factors are applied to the integrated Bragg intensities only. Furthermore, it is possible to assign different linear attenuation coefficients to the paths of the incident and scattered beams, as is desirable, for instance, in the case of X-ray holography with an internal resonant scatterer. Broad diffuse scattering data collected with synchrotron radiation and numerical calculations are used to study in detail the influence of experimental parameters on the accuracy of the pixel-wise absorption correction.

scholarly journals An approach to high-throughput X-ray diffraction analysis of combinatorial polycrystalline thin film libraries

2009 ◽  
Vol 42 (2) ◽  
pp. 174-178 ◽  
Author(s):  
S. Roncallo ◽  
O. Karimi ◽  
K. D. Rogers ◽  
D. W. Lane ◽  
S. A. Ansari
Keyword(s):  
High Throughput ◽  
Lattice Parameter ◽  
Scattering Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Raster Scanning ◽  
Area Detector ◽  
Large Numbers ◽  
Potential Applications ◽  
Compositional Gradients

With the demand for higher rates of discovery in the materials field, characterization techniques that are capable of rapidly and reliably surveying the characteristics of large numbers of samples are essential. A chemical combinatorial approach using thin films can provide detailed phase diagrams without the need to produce multiple, individual samples. This is achieved with compositional gradients forming high-density libraries. Conventional raster scanning of chemical or structural probes is subsequently used to interrogate the libraries. A new, alternative approach to raster scanning is introduced to provide a method of high-throughput data collection and analysis using an X-ray diffraction probe. Libraries are interrogated with an extended X-ray source and the scattering data collected using an area detector. A simple technique of `partitioning' this scattering distribution enables determination of information comparable to conventional raster scanned results but in a dramatically reduced collection time. The technique has been tested using synthetic X-ray scattering distributions and those obtained from contrived samples. In all cases, the partitioning algorithm is shown to be robust and to provide reliable data; discrimination along the library principal axis is shown to be ∼500 µm and the lattice parameter resolution to be ∼10−3 Å mm−1. The limitations of the technique are discussed and future potential applications described.

scholarly journals Processing two-dimensional X-ray diffraction and small-angle scattering data inDAWN 2

2017 ◽  
Vol 50 (3) ◽  
pp. 959-966 ◽  
Author(s):  
J. Filik ◽  
A. W. Ashton ◽  
P. C. Y. Chang ◽  
P. A. Chater ◽  
S. J. Day ◽  
...  
Keyword(s):  
Data Processing ◽  
Small Angle ◽  
Scattering Data ◽  
Data Provenance ◽  
Complex Data ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Full Data ◽  
X Ray ◽  
Data Files

A software package for the calibration and processing of powder X-ray diffraction and small-angle X-ray scattering data is presented. It provides a multitude of data processing and visualization tools as well as a command-line scripting interface for on-the-fly processing and the incorporation of complex data treatment tasks. Customizable processing chains permit the execution of many data processing steps to convert a single image or a batch of raw two-dimensional data into meaningful data and one-dimensional diffractograms. The processed data files contain the full data provenance of each process applied to the data. The calibration routines can run automatically even for high energies and also for large detector tilt angles. Some of the functionalities are highlighted by specific use cases.

Determination of Shearing Stresses (τxz and τyz) Using X-Ray Diffraction Method with Two-Dimensional Detector

2012 ◽  
Vol 706-709 ◽  
pp. 1719-1724
Author(s):  
Toshihiko Sasaki ◽  
Junichi Akita ◽  
Yasutomo Sone ◽  
Yuichi Kobayashi
Keyword(s):  
Present Method ◽  
Lattice Spacing ◽  
Diffraction Method ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Area Detector ◽  
Debye Ring ◽  
Detector Type

Measurement of shearing stresses, τxzand τyz, by X-ray diffraction technique with two-dimensional detector was studied. The principle which was developed for an area detector type X-ray triaxial stress analysis was adopted for this purpose. In the present method, Debye ring was measured first and its whole part was used for determining shearing stresses. One Debye ring is enough to determine shearing stresses without accurate diffraction data such as lattice spacing in stress free. The result of the simulation showed that the present method is useful for the evaluation of shearing stresses by X-ray diffraction technique.

Determination of crystal orientation by an area-detector image for surface X-ray diffraction

2005 ◽  
Vol 38 (2) ◽  
pp. 319-323
Author(s):  
Wataru Yashiro ◽  
Shuji Kusano ◽  
Kazushi Miki
Keyword(s):  
Conventional Method ◽  
Crystal Orientation ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Area Detector ◽  
Crystal Truncation Rod ◽  
Orientation Matrix ◽  
Sample Alignment

A new method of calculating the crystal orientation matrix (Umatrix) of a specified sample using two-dimensional X-ray diffraction spots that are recorded on an area detector is presented. In this way, theUmatrix is calculated using at least three two-dimensional diffraction spots of known two-dimensional indices, which provide the projection of the crystal truncation rod onto the detector. The method, in the case of surface X-ray diffraction measurements with an area detector, enables easier and faster sample alignment than the conventional method to determine theUmatrix.

Wide Angle and Small Angle X-ray Scattering Applications Using a Two-Dimensional Area Detector

1990 ◽  
Vol 34 ◽  
pp. 363-368
Author(s):  
B. G. Landes ◽  
R. A. Newman ◽  
P. R. Rudolf
Keyword(s):  
Dynamic Range ◽  
Scattering Data ◽  
Photographic Film ◽  
Scanning System ◽  
Imaging Plate ◽  
Two Dimensional ◽  
X Ray ◽  
Area Detector ◽  
X Ray Scattering ◽  
Ray Scattering

The traditional medium for collecting two-dimensional x-ray scattering patterns is photographic film. While x-ray film has excellent resolution, several factors make it a poor choice as a detection device: slow speed, limited dynamic range, the “human factor” (developing, fixing, film handling), and the lack of a commercial scanning system designed for reading two-dimensional x-ray films. Until recently, there were no practical alternatives to the use of photographic film for obtaining two-dimensional x-ray scattering data using a conventional x-ray source. In the past few years, two different detection systems have become available for collecting high quality two-dimensional x-ray scattering data: (1) the Siemens (Xentronics) area detector system, which is a gas filled, wire grid detector, and (2) the Fuji imaging-plate system, which utilizes a phosphor storage plate for imaging the x-ray scattering and a laser scanner to process the image.

scholarly journals Determination of crystal size distribution by two-dimensional X-ray diffraction

2014 ◽  
Vol 70 (a1) ◽  
pp. C1131-C1131
Author(s):  
Alejandro Rodriguez-Navarro ◽  
Krzysztof Kudłacz
Keyword(s):  
Size Distribution ◽  
Crystal Size ◽  
High Sensitivity ◽  
Crystal Size Distribution ◽  
Polycrystalline Materials ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Area Detector ◽  
Diffraction Patterns

Polycrystalline materials properties and behaviour are ultimately determined by their crystallinity, phase composition and microstructure (i.e., crystal size, preferential orientation). Two-dimensional (2D) diffraction patterns collected with an area detector (i.e., CDD), available in modern X-ray diffractometers, contain detailed information about all these important material characteristics. Furthermore, recent advances in detector technologies permits the collection of high resolution diffraction patterns in which the microstructure of the material can be directly imaged. If the size of beam relative to the crystal size in the sample is adequately choosen, the diffraction pattern produced will have spotty rings in which the spots are the diffracted images of individual grains. The resolution of the image is mainly dependent on the characteristics of the X-ray beam (i.e., diameter, angular divergence), which can be modulated by X-ray optics, sample to detector distance, the pixel size of the detector and the sharpness of the point spread function. From these patterns, the crystal size distribution of different crystalline phases present in the sample can be independently determined using specialized software capable of extracting and combining the information contained in these patterns. This technique is applicable to materials with crystal sizes ranging from submicron to mm sizes and is complementary to techniques based on peak profile analyses (i.e., Scherrer method) which are applicable only to nanocrystalline materials. Finally, given the high sensitivity of current detectors, crystal size evolution can be followed in real-time to study important transformation processes such as crystallization, annealing, etc. The use of 2D X-ray diffraction as applied to microstructure characterization will be illustrated through several examples.

XRD2DScan: new software for polycrystalline materials characterization using two-dimensional X-ray diffraction

2006 ◽  
Vol 39 (6) ◽  
pp. 905-909 ◽  
Author(s):  
Alejandro B. Rodriguez-Navarro
Keyword(s):  
Polycrystalline Materials ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Area Detector ◽  
Multiple Data ◽  
Different Types ◽  
Ψ Angle ◽  
Data Files ◽  
Diffraction Patterns

XRD2DScanis a Windows application for displaying and analyzing two-dimensional X-ray diffraction patterns collected with an area detector. This software allows users to take full advantage of diffractometers that are equipped with an area detector but that cannot readily process the information contained in diffraction patterns from polycrystalline materials.XRD2DScanhas many capabilities for generating different types of scans (2θ scan, ψ scan,dspacingversusψ angle), which allows users to extract the maximum amount of information from two-dimensional patterns. Analyses of multiple data files can be fully automated using batch processing. The use of the software is illustrated through several examples.

MicroGap Area Detector for Stress and Texture Analysis

2011 ◽  
Vol 681 ◽  
pp. 19-24
Author(s):  
Bob B. He
Keyword(s):  
Texture Analysis ◽  
High Performance ◽  
High Efficiency ◽  
X Rays ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Large Area ◽  
Ray Optics ◽  
X Ray ◽  
Area Detector

Two-dimensional x-ray diffraction is an ideal method for examining the residual stress and texture. The most dramatic development in two-dimensional x-ray diffractometry involves three critical devices, including x-ray sources, x-ray optics and detectors. The recent development in brilliant x-rays sources and high efficiency x-ray optics provided high intensity x-ray beam with the desired size and divergence. Correspondingly, the detector used in such a high performance system requires the capability to collect large two-dimensional images with high counting rate and high resolution. This paper introduces the diffraction vector approach in two-dimensional x-ray diffraction for stress and texture analysis, and an innovative large area detector based on the MikroGap™ technology.

Tubulin structure at intermediate resolution

1995 ◽  
Vol 53 ◽  
pp. 852-853
Author(s):  
K. H. Downing ◽  
S. G. Wolf ◽  
E. Nogales
Keyword(s):  
High Resolution ◽  
Structural Data ◽  
Therapeutic Drug ◽  
Zinc Ions ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Negative Stain ◽  
Functional Mechanisms ◽  
Tubulin Structure

Microtubules are involved in a host of critical cell activities, many of which involve transport of organelles through the cell. Different sets of microtubules appear to form during the cell cycle for different functions. Knowledge of the structure of tubulin will be necessary in order to understand the various functional mechanisms of microtubule assemble, disassembly, and interaction with other molecules, but tubulin has so far resisted crystallization for x-ray diffraction studies. Fortuitously, in the presence of zinc ions, tubulin also forms two-dimensional, crystalline sheets that are ideally suited for study by electron microscopy. We have refined procedures for forming the sheets and preparing them for EM, and have been able to obtain high-resolution structural data that sheds light on the formation and stabilization of microtubules, and even the interaction with a therapeutic drug.Tubulin sheets had been extensively studied in negative stain, demonstrating that the same protofilament structure was formed in the sheets and microtubules. For high resolution studies, we have found that the sheets embedded in either glucose or tannin diffract to around 3 Å.

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