Comparison of diffraction intensity using a monocapillary optic and pinhole collimators in a microdiffractometer with a curved image-plate

2002 ◽  
Vol 17 (2) ◽  
pp. 94-98 ◽  
Author(s):  
Paul J. Schields ◽  
Igor Yu. Ponomarev ◽  
Ning Gao ◽  
Richard B. Ortega
Keyword(s):  
Beam Width ◽  
X Rays ◽  
Average Increase ◽  
Diffraction Intensity ◽  
Image Plate ◽  
Integrated Intensity ◽  
Diffraction Peaks ◽  
Diffraction Patterns ◽  
Image Plate System ◽  
Pinhole Collimators

The performance of a tapered, monocapillary optic was compared to double-pinhole optics by measuring the intensity and widths of powder diffraction peaks generated using Cr Kα and Cu Kα X-rays (46 kV, 46 mA). A microdiffractometer and curved image-plate system was used to collect diffraction patterns displayed by an alumina intensity standard. A monocapillary optic with a 20 μm beam width (measured at half the maximum intensity, FWHM) was compared to collimating pinhole optics with two apertures: one with 30 μm diameter pinholes and another with 50 μm pinholes. The average, integrated intensity of the diffraction peaks in the patterns collected using the 20 μm monocapillary optic was 6 to 7 times greater than the average diffraction intensity obtained with the 50 μm pinhole collimator and 25 times greater than the intensity obtained with the 30 μm collimator. The average increase in the FWHM of the diffraction peaks in the patterns obtained with the monocapillary optic was ∼2 times greater than the pinhole collimators.

Characterization of image plates for neutron diffraction

2009 ◽  
Vol 42 (5) ◽  
pp. 749-757 ◽  
Author(s):  
Clive Wilkinson ◽  
Mogens S. Lehmann ◽  
Flora Meilleur ◽  
Matthew P. Blakeley ◽  
Dean A. A. Myles ◽  
...  
Keyword(s):  
Point Spread Function ◽  
X Rays ◽  
Image Plate ◽  
Point Spread ◽  
Spread Function ◽  
Luminescent Signal ◽  
Diffraction Patterns ◽  
Integrated Intensities ◽  
Ccd Detectors ◽  
Lower Limits

A method to measure the overall gain and point-spread function of an image-plate detector system (converter, phosphor, readout electronics) online from single-crystal diffraction patterns is derived. Only with a knowledge of these quantities can one estimate without bias the true standard deviations of the observed integrated intensities of Bragg reflections measured with such a detector. The gain corrected for the point-spread function should ideally be approximately 1.0 to avoid loss of data or precision due to the upper and lower limits of digitization of the diffraction patterns. The gain and the point-spread function are derived for several configurations of the three neutron Laue image-plate diffractometers, LADI, VIVALDI and LADI-III, at the Institut Laue–Langevin. The detective quantum efficiencies (DQE) of these instruments have been measured to be 0.16 (1), 0.57 (2) and 0.46 (3), respectively. It has also been found that the DQE is effectively constant for different times of exposure, despite the fading of the photostimulated luminescent signal during that time. While the results described in this paper concern neutron detection by image plates, the method is equally valid for other integrating detectors and radiations,e.g.CCD detectors and X-rays.

Structural studies of small amorphous volumes by electron diffraction

1990 ◽  
Vol 48 (4) ◽  
pp. 122-123
Author(s):  
Pierre Moine
Keyword(s):  
Electron Diffraction ◽  
Born Approximation ◽  
Structural Information ◽  
Fundamental Relation ◽  
X Rays ◽  
Structural Studies ◽  
Diffraction Experiment ◽  
Transmission Electron ◽  
Amorphous Structures ◽  
Diffraction Patterns

Qualitatively, amorphous structures can be easily revealed and differentiated from crystalline phases by their Transmission Electron Microscopy (TEM) images and their diffraction patterns (fig.1 and 2) but, for quantitative structural information, electron diffraction pattern intensity analyses are necessary. The parameters describing the structure of an amorphous specimen have been introduced in the context of scattering experiments which have been, so far, the most used techniques to obtain structural information in the form of statistical averages. When only small amorphous volumes (< 1/μm in size or thickness) are available, the much higher scattering of electrons (compared to neutrons or x rays) makes, despite its drawbacks, electron diffraction extremely valuable and often the only feasible technique.In a diffraction experiment, the intensity IN (Q) of a radiation, elastically scattered by N atoms of a sample, is measured and related to the atomic structure, using the fundamental relation (Born approximation) : IN(Q) = |FT[U(r)]|.

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

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.

Morphological and synchrotron X-ray microdiffraction studies of large columnar CVD diamond crystallites

1999 ◽  
Vol 32 (5) ◽  
pp. 924-933 ◽  
Author(s):  
A. R. Lang ◽  
A. P. W. Makepeace ◽  
J. E. Butler
Keyword(s):  
Vapour Deposition ◽  
Chemical Vapour ◽  
Coarse Grained ◽  
X Rays ◽  
Small Cross Section ◽  
X Ray ◽  
Chemical Vapour Deposition Diamond ◽  
Core Column ◽  
Diffraction Patterns ◽  
Goniometric Measurements

Optical microscopic and goniometric measurements were combined with microradiography, diffraction-pattern analysis and topography to study a 2 mm thick [001]-texture CVD (chemical vapour deposition) diamond film that had developed a coarse-grained structure composed of separate columnar crystallites. Individual columns were capped by large (001) facets, with widths up to 0.5 mm, and which were smooth but not flat, whereas the column sides were morphologically irregular. The refractive deviation of X-rays transmitted through the crystallites was exploited for delineating facet edges, thereby facilitating the controlled positioning of small-cross-section X-ray beams used for recording diffraction patterns from selected volumes in two representative crystallites. Their structure consisted of a [001]-axial core column surrounded by columns in twin orientation with respect to the core. The diamond volume directly below the (001) facets was free from low-angle boundaries, and no dislocation outcrops on the facets were detected. Significant elastic deformation of this volume was only present close to the facet periphery, where misorientations reached a few milliradians. Lattice imperfection was high in the twins, with ∼1° misorientations.

Crystallization and preliminary structural studies of Scilla campanulata lectin complexed with α1–6 mannobiose

1998 ◽  
Vol 54 (1) ◽  
pp. 90-92 ◽  
Author(s):  
Lisa M Wright ◽  
Stephen D. Wood ◽  
Colin D. Reynolds ◽  
Pierre J. Rizkallah ◽  
Anthony K. Allen
Keyword(s):  
Molecular Replacement ◽  
X Rays ◽  
Synchrotron Source ◽  
Replacement Method ◽  
Cell Dimensions ◽  
Molecular Replacement Method ◽  
Hanging Drop Method ◽  
Unit Cell Dimensions ◽  
Antiretroviral Activity ◽  
Image Plate System

Recent work has shown that Scilla campanulata agglutinin from bluebell bulbs has a strong affinity for α(1,3)- and α(1,6)-linked mannosyl residues and possesses moderate antiretroviral activity. This lectin has been crystallized by the hanging-drop method of vapour diffusion complexed with the disaccharide mannose-α1,6-D-mannose. The crystals are in the space group P21212 with unit-cell dimensions a = 70.63, b = 92.79 and c = 47.25 Å, and with a dimer in the asymmetric unit. The crystals diffract X-rays to beyond 1.5 Å resolution at 277 K and are stable in an X-ray beam. Data to 1.6 Å resolution have been collected using a MAR image-plate system at a synchrotron source and the structure of the complex has been solved by the molecular replacement method.

scholarly journals Hard X-ray polarizer to enable simultaneous three-dimensional nanoscale imaging of magnetic structure and lattice strain

2016 ◽  
Vol 23 (5) ◽  
pp. 1210-1215 ◽  
Author(s):  
Jonathan Logan ◽  
Ross Harder ◽  
Luxi Li ◽  
Daniel Haskel ◽  
Pice Chen ◽  
...  
Keyword(s):  
Magnetic Circular Dichroism ◽  
Three Dimensional ◽  
Control Sample ◽  
Magnetic Ordering ◽  
X Rays ◽  
Diffractive Imaging ◽  
X Ray ◽  
Coherent Diffractive Imaging ◽  
Diffraction Patterns ◽  
A New Technique

Recent progress in the development of dichroic Bragg coherent diffractive imaging, a new technique for simultaneous three-dimensional imaging of strain and magnetization at the nanoscale, is reported. This progress includes the installation of a diamond X-ray phase retarder at beamline 34-ID-C of the Advanced Photon Source. The performance of the phase retarder for tuning X-ray polarization is demonstrated with temperature-dependent X-ray magnetic circular dichroism measurements on a gadolinium foil in transmission and on a Gd5Si2Ge2crystal in diffraction geometry with a partially coherent, focused X-ray beam. Feasibility tests for dichroic Bragg coherent diffractive imaging are presented. These tests include (1) using conventional Bragg coherent diffractive imaging to determine whether the phase retarder introduces aberrations using a nonmagnetic gold nanocrystal as a control sample, and (2) collecting coherent diffraction patterns of a magnetic Gd5Si2Ge2nanocrystal with left- and right-circularly polarized X-rays. Future applications of dichroic Bragg coherent diffractive imaging for the correlation of strain and lattice defects with magnetic ordering and inhomogeneities are considered.

scholarly journals In Situ Observation Technique of High-temperature Reactions Using a New Image-plate System at Synchrotron Radiation

1999 ◽  
Vol 85 (2) ◽  
pp. 169-173 ◽  
Author(s):  
Masao KIMURA ◽  
Muneyuki IMAFUKU ◽  
Masao KUROSAKI ◽  
Siro FUJII ◽  
Yasuhide MORIMOTO
Keyword(s):  
High Temperature ◽  
Synchrotron Radiation ◽  
Image Plate ◽  
High Temperature Reactions ◽  
Plate System ◽  
Image Plate System

A High-Energy Monochromatic Laue (MonoLaue) X-ray Diffuse Scattering Study of KMnF3 using an Image Plate

1997 ◽  
Vol 30 (1) ◽  
pp. 16-20 ◽  
Author(s):  
A. Gibaud ◽  
D. Harlow ◽  
J. B. Hastings ◽  
J. P. Hill ◽  
D. Chapman
Keyword(s):  
Diffuse Scattering ◽  
High Energy ◽  
Experimental Conditions ◽  
X Ray ◽  
Image Plate ◽  
X Ray Scattering ◽  
Scattering Study ◽  
Diffraction Patterns ◽  
Ray Scattering

The technique of high-energy monochromatic Laue X-ray scattering using image plates to record the diffraction patterns is presented. A tunable wiggler beamline is used as an X-ray source. It is shown that such experimental conditions present many advantages over conventional tube sources and photographic films. A study of diffuse scattering in the perovskite compound KMnF3 is presented to illustrate this in a qualitative way.

Detection of a metallic glass layer by x-ray diffraction

1986 ◽  
Vol 1 (5) ◽  
pp. 629-634 ◽  
Author(s):  
J.W. McCamy ◽  
M.J. Godbole ◽  
A.J. Pedraza ◽  
D.H. Lowndes
Keyword(s):  
Target Material ◽  
Amorphous Layer ◽  
Glass Layer ◽  
X Rays ◽  
Average Thickness ◽  
X Ray Diffraction ◽  
Near Surface ◽  
X Ray ◽  
Integrated Intensity ◽  
Thickness Measurements

A simple, precise method for obtaining the average thickness of an amorphous layer formed by any surface treatment has been developed. The technique uses an x-ray diffractoeter to measure the reduction in the integrated intensity of several diffracted x-ray lines due to the near surface amorphous layer. The target material for generation of x rays is selected so that the emitted x rays are strongly absorbed by the specimen. This method permits thickness measurements down to ∼ 100 nm. It has been tested on a specimen of Fe80B20 on which an amorphous layer was produced by pulsed XeCl (308 nm) laser irradiation; the amorphous layer thickness was found to be 1.34 (∼0.1) um.

Kinematical two-dimensional multiple-diffraction intensity profiles. Application to ω–ψ scans of silicon and diamond obtained with synchrotron radiation

2001 ◽  
Vol 34 (2) ◽  
pp. 157-165 ◽  
Author(s):  
E. Rossmanith ◽  
A Hupe ◽  
R. Kurtz ◽  
H. Schmidt ◽  
H.-G. Krane
Keyword(s):  
Synchrotron Radiation ◽  
Incident Beam ◽  
Mosaic Structure ◽  
Two Dimensional ◽  
Diffraction Intensity ◽  
Multiple Diffraction ◽  
Crystal Sample ◽  
Diffraction Patterns ◽  
Kinematical Theory

In a previous paper by Rossmanith [J. Appl. Cryst.(2000),33, 1405–1414], expressions for the calculation of multiple-diffraction patterns observed in ω–ψ scans of Bragg reflections were derived within the framework of the kinematical theory, taking into account the divergence and wavelength spread of the incident beam, as well as the mosaic structure of the crystal sample. Agreement with CuKα experiments was demonstrated. In this paper, it is shown that the theoretical expressions are also suitable for synchrotron radiation experiments.

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