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.

An XRPD Investigation of a Face-Centered Cubic Metallic Plating

1986 ◽  
Vol 1 (2) ◽  
pp. 22-27 ◽  
Author(s):  
Clay Olaf Ruud ◽  
Robin J. McDowell ◽  
Daniel J. Snoha
Keyword(s):  
Residual Stress ◽  
Elastic Strain ◽  
Intensity Variation ◽  
Face Centered Cubic ◽  
Nickel Plating ◽  
Polycrystalline Nickel ◽  
X Ray ◽  
Position Sensitive ◽  
Face Centered ◽  
Crystallographic Planes

AbstractInternal elastic strain (i.e., residual stress) and the diffracted X-ray intensity variation over several orientations of crystallites with respect to the specimen surface were investigated as a means of differentiating two qualities of polycrystalline nickel plating. A unique instrument based upon a position-sensitive scintillation X-ray detector was used to apply all of the techniques commonly applied to X-ray stress analysis in this investigation. It was concluded that residual stress measurements did not provide a clear distinction between the two specimens, but comparison of the relative intensities diffracted from crystallographic planes at certain orientations with the surface did provide a distinction.

Application of a multichannel position-sensitive X-ray detector to protein crystallography

1981 ◽  
Vol 14 (1) ◽  
pp. 33-37 ◽  
Author(s):  
T. D. Mokulskaya ◽  
S. V. Kuzev ◽  
G. E. Myshko ◽  
A. A. Khrenov ◽  
M. A. Mokulskii ◽  
...  
Keyword(s):  
Protein Crystallography ◽  
X Ray ◽  
Position Sensitive

X-ray position-sensitive detectors

1986 ◽  
Vol 19 (3) ◽  
pp. 145-163 ◽  
Author(s):  
U. W. Arndt
Keyword(s):  
X Rays ◽  
Two Dimensional ◽  
Physical Processes ◽  
X Ray ◽  
General Terms ◽  
Position Sensitive ◽  
Position Sensitive Detectors

The physical processes are examined which can be used for the detection of X-rays in the range between about 3 and about 20 keV and for the positional localization of the incident photons. The criteria for choosing a detector for particular purposes are discussed in general terms. Specific examples of one- and two-dimensional detectors are then considered with particular emphasis on devices which are still in a state of development, and an attempt is made to summarize the nature, performance and suitability for different experiments of available detectors.

Micro Diffraction Imaging of Bulk Polycrystalline Materials

2006 ◽  
Vol 524-525 ◽  
pp. 273-278
Author(s):  
Thomas Wroblewski ◽  
A. Bjeoumikhov ◽  
Bernd Hasse
Keyword(s):  
High Spatial Resolution ◽  
Polycrystalline Materials ◽  
X Rays ◽  
X Ray Diffraction ◽  
Short Sample ◽  
X Ray ◽  
Detector Distance ◽  
Transmission Geometry ◽  
Diffraction Imaging ◽  
Position Sensitive

X-ray diffraction imaging applies an array of parallel capillaries in front of a position sensitive detector. Conventional micro channel plates of a few millimetre thickness have successfully been used as collimator arrays but require short sample to detector distances to achieve high spatial resolution. Furthermore, their limited absorption restricts their applications to low energy X-rays of around 10 keV. Progress in the fabrication of long polycapillaries allows an increase in the sample to detector distance without decreasing resolution and the use of high X-ray energies enables bulk investigations in transmission geometry.

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