Related Experiment Video
Updated: Aug 29, 2026

Characterization of Ultra-fine Grained and Nanocrystalline Materials Using Transmission Kikuchi Diffraction
Published on: April 1, 2017
Secondary extinction and diffraction behaviors in cylindrical crystals
1China Institute of Atomic Energy, PO Box 275 (18), Beijing 102413, People's Republic of China. hchu@ht.rol.cn.net
Abstract:
The X-ray and neutron diffraction properties in absorbing cylindrical crystals are systematically explored within the framework of transfer equations and the kinematic diffraction approximation. The calculated power ratio distribution, the integrated reflection power ratio and the secondary-extinction factor y( micro ) are expressed as functions of the Bragg angle theta(B), the reduced radius sigma(0)rho = tau(0) and the ratio of absorption coefficient to diffraction cross section micro /sigma(0) = xi(0). Numerical solutions were obtained for all theta(B) (0-90 degrees ) and samples with tau(0) from 0 to 30, and xi(0) from 0 to 25. The relationship between the power ratio distribution curves, the integrated reflection power ratio and the diffraction geometry of cylindrical crystals is obtained for the first time and analyzed in detail. A dip was found in the curve of the extinction factor y( micro ) against tau(0) for given theta(B) and xi(0), and the position of this minimum shifts toward smaller tau(0) with increasing xi(0) or theta(B). A large decrease of y( micro ) with decreasing theta(B) at low angle appears when micro rho > 3.5 and 25 > xi(0) > 0.2. The rate of change of y( micro ) in this region increases with tau(0). All of this will be important for the refinement of diffraction data. The influence of different kinds of mosaic distributions on the integrated reflection power ratio and the extinction factor was also studied. The transmission coefficients A(*) were calculated using two different methods, and an inaccuracy of these numbers in Vol. II of International Tables for X-ray Crystallography (1972) in the range theta(B) < or = 15 degrees and micro rho > or = 15 was found by comparison.
More Related Videos
08:44Measurements of Long-range Electronic Correlations During Femtosecond Diffraction Experiments Performed on Nanocrystals of Buckminsterfullerene
Published on: August 22, 2017
11:48Microfluidic Chips for In Situ Crystal X-ray Diffraction and In Situ Dynamic Light Scattering for Serial Crystallography
Published on: April 24, 2018
Related Concept Videos
Interference and Diffraction
X-ray Crystallography
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
X-ray Diffraction of Biological Samples
According to Bragg's law, when X-rays strike the sample positioned on a stage, the rays are scattered by the electron clouds around the sample atoms. The X-ray diffraction or scattering is caused by constructive interference of the X-ray waves that reflect off the internal crystal...
Law of Rational Indices
Determination of Crystal Structures
Imperfections in Crystal Structure: Point, Line and Plane Defects