scholarly journals Focusing of hard X-ray beams in quartz crystal under the temperature gradient

2014 ◽  
Vol 70 (a1) ◽  
pp. C1137-C1137
Author(s):  
Vahan Kocharyan ◽  
Sargis Khlopuzyan ◽  
Poghos Grigoryan ◽  
Edik Baghdasaryan ◽  
Ruben Amiraghyan
Keyword(s):  
Temperature Gradient ◽  
Plane Wave ◽  
Quartz Crystal ◽  
Spectral Width ◽  
X Rays ◽  
Ultrasonic Vibrations ◽  
Diffraction Vector ◽  
Wave Fronts ◽  
X Ray ◽  
Focus Point

The research of the focusing and defocusing of the diffracted X-rays with different wave fronts in crystals under the influences of the temperature gradient and the ultrasonic vibrations is given in the works [1,2]. This work is dedicated experimentally investigation of Laue diffraction of the hard X-rays in quartz single crystals under the influence of the temperature gradient. It is shown that the reflected beams under the influence of the temperature gradient are focused. When the vector of the temperature gradient is anti parallel to the diffraction vector, in accordance to the increasing value of the temperature gradient the focus point continuously approaches the crystal. When the vector of the temperature gradient is parallel to the diffraction vector, in accordance with the increasing value of the temperature gradient the focus point continuously distances itself from the crystal, and at a certain value of the temperature gradient it becomes a plane wave. Parallel to the further increasing of the temperature gradient we see an imaginary focus, which continuously approaches the entry surface of the crystal. It is shown that by using a thicker single crystal it is possible to focus and pump a larger angular and spectral width of X-rays in the direction of diffraction.

X-Ray Absorption Coefficient Behavior Depending on Disposition of Diffraction Vector and Temperature Gradient Vector

2015 ◽  
Vol 1084 ◽  
pp. 342-345 ◽  
Author(s):  
Karlen Hayrapetyan ◽  
Serob Noreyan ◽  
Vardan Margaryan ◽  
Vahan Kocharyan
Keyword(s):  
Temperature Gradient ◽  
Absorption Coefficient ◽  
X Rays ◽  
Gradient Vector ◽  
Diffraction Vector ◽  
Physical Explanation ◽  
Good Correspondence ◽  
X Ray ◽  
X Ray Absorption ◽  
Laue Geometry

The behavior of the interference absorption coefficient of X-rays in Laue geometry depending upon the disposition of diffraction vector and temperature gradient vector in the perpendicular direction to the reflecting atomic planes family was experimentally studied. The study was carried out for the different thicknesses of quartz single crystal for atomic planes. It was shown that in the case of anti-parallel disposition of the diffraction vector and temperature gradient vector the absorption coefficient of X-rays sharply decreases with the increase of temperature gradient and in the case of the parallel disposition of the diffraction vector and the temperature gradient vector the absorption coefficient firstly increases and then decreases. The theoretical calculation corresponding to the experiment conditions have been done. The physical explanation of the obtained experimental results has been made. The obtained results are in good correspondence with the experiment.

Plane-wave X-ray images of dislocations parallel to the diffraction vector

1984 ◽  
Vol 83 (1) ◽  
pp. 195-205 ◽  
Author(s):  
V. L. Indenbom ◽  
V. M. Kaganer ◽  
W. Möhling ◽  
E. V. Suvorov
Keyword(s):  
Plane Wave ◽  
Diffraction Vector ◽  
X Ray

scholarly journals The anisotropy in the optical constants of quartz crystals for soft X-rays

2021 ◽  
Vol 54 (2) ◽  
Author(s):  
A. Andrle ◽  
P. Hönicke ◽  
J. Vinson ◽  
R. Quintanilha ◽  
Q. Saadeh ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Experimental Data ◽  
Refractive Index ◽  
Optical Constants ◽  
Quartz Crystal ◽  
Crystal Surface ◽  
X Rays ◽  
Data Set ◽  
Quartz Crystals ◽  
X Ray

The refractive index of a y-cut SiO2 crystal surface is reconstructed from orientation-dependent soft X-ray reflectometry measurements in the energy range from 45 to 620 eV. Owing to the anisotropy of the crystal structure in the (100) and (001) directions, a significant deviation of the measured reflectance at the Si L 2,3 and O K absorption edges is observed. The anisotropy in the optical constants reconstructed from these data is also confirmed by ab initio Bethe–Salpeter equation calculations for the O K edge. This new experimental data set expands the existing literature data for quartz crystal optical constants significantly, particularly in the near-edge regions.

scholarly journals Texture and Lamellae Distribution Functions in Lamellar Eutectics

1986 ◽  
Vol 6 (4) ◽  
pp. 265-287 ◽  
Author(s):  
H. J. Bunge
Keyword(s):  
Three Dimensional ◽  
Orientation Distribution ◽  
Distribution Functions ◽  
X Rays ◽  
Two Dimensional ◽  
Absorption Factor ◽  
X Ray Diffraction ◽  
Diffraction Vector ◽  
X Ray ◽  
Pole Figures

The crystallographic orientation distribution and the geometrical lamellae orientation distribution in lamellar eutectics are, in general, not independent of each other. The combined orientation-lamellae distribution function depends on five angular parameters. X-ray diffraction in such eutectics may exhibit an anisotropic macroscopic absorption factor if the penetration depth of the X-rays is large compared with their planar size. As a consequence, the reflected X-ray intensity may depend on a third angle γ, i.e. a rotation of the sample about the diffraction vector s additionally to the usual pole figure angles α, β which describe the orientation of the diffraction vector s with respect to the sample coordinate system. It is thus necessary to measure three-dimensional generalized pole figures instead of conventional two-dimensional ones.

scholarly journals Influence of temperature gradient on diffracted X-ray spectrum in quartz crystal

2016 ◽  
Vol 135 ◽  
pp. 012028
Author(s):  
A R Mkrtchyan ◽  
A P Potylitsyn ◽  
A V Vukolov ◽  
A I Novokshonov ◽  
A S Gogolev ◽  
...  
Keyword(s):  
Temperature Gradient ◽  
Quartz Crystal ◽  
Influence Of Temperature ◽  
X Ray

Effect of the Temperature Gradient on the X-ray Diffraction Spectrum of a Quartz Crystal

2017 ◽  
Vol 11 (6) ◽  
pp. 1109-1112
Author(s):  
A. R. Mkrtchyan ◽  
A. P. Potylitsyn ◽  
A. V. Vukolov ◽  
A. I. Novokshonov ◽  
A. S. Gogolev ◽  
...  
Keyword(s):  
Temperature Gradient ◽  
Quartz Crystal ◽  
Diffraction Spectrum ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Numerical Calculation of Anisotropic Absorption Factors for Lamellar Two-Phase Structures

1990 ◽  
Vol 12 (4) ◽  
pp. 199-217
Author(s):  
Y. S. Liu ◽  
H. J. Bunge
Keyword(s):  
Numerical Calculation ◽  
Sample Surface ◽  
X Rays ◽  
Absorption Factor ◽  
X Ray Diffraction ◽  
Diffraction Vector ◽  
Absorption Coefficients ◽  
Two Phase ◽  
X Ray ◽  
Phase Structures

X-ray diffraction in a lamellar two-phase material is considered. If the lamellae thicknesses are small compared with the penetration depth of the X-rays then the absorption factor depends on the whole path of incident and reflected beam in both phases. Particularly, it depends on a rotation γ about the diffraction vector s additional to the orientation (αβ) of this vector with respect to the sample. Numerical calculations of the absorption factor A(αβγ) have been carried out for different values of lamellae thicknesses D1D2, absorption coefficients μ1μ2 and lamellae orientations ωρ with respect to the sample surface.

Improvement of Compact X-Rays Source Using Uniaxially Polarized LiNbO3 Single Crystal

2010 ◽  
Vol 445 ◽  
pp. 43-46 ◽  
Author(s):  
Yang Guan ◽  
Shinji Fukao ◽  
Kazuyuki Ito ◽  
Yoshikazu Nakanishi ◽  
Yuuki Sato ◽  
...  
Keyword(s):  
Temperature Gradient ◽  
Electric Field ◽  
Single Crystal ◽  
Single Crystals ◽  
Field Intensity ◽  
Electric Field Intensity ◽  
X Rays ◽  
X Ray ◽  
Radiation Equipment ◽  
The Stability

X-ray radiation using pyroelectric crystal is intermittent and the X-ray intensity is low and unstable compared with a conventional X-ray radiation method, such as X-ray tube. It is expected that the X-ray intensity becomes stable if electric field intensity and supply of electron are stable. In this study, to use X-ray radiation equipment as an electron source, tandem-type X-ray radiation equipment which is composed of two LiNbO3 single crystals polarized in a z-axis is proposed. When the temperature gradient for each crystal was the same, the X-ray intensity became approximately 6 times higher at a maximum. When the temperature gradient for each crystal was reversed, the period of X-ray radiation became approximately two times longer and the X-ray intensity became approximately 20 times higher at a maximum. Moreover, the stability of X-ray radiation for the repetition of temperature could be improved.

Sign in / Sign up

Export Citation Format

Share Document