Theoretical considerations in the construction of hard X-ray resonators at inclined incidence with ultra-high efficiency and resolution

2016 ◽  
Vol 49 (5) ◽  
pp. 1653-1658 ◽  
Author(s):  
Y.-H. Wu ◽  
Y.-Y. Chang ◽  
Y.-W. Tsai ◽  
S.-L. Chang
Keyword(s):  
High Efficiency ◽  
Incident Beam ◽  
Normal Incidence ◽  
Dynamical Theory ◽  
X Ray ◽  
Multiple Beam ◽  
Back Reflection ◽  
Diffraction Geometry ◽  
Fabry Perot ◽  
Beam Diffraction

Detailed considerations of how to construct inclined-incidence hard X-ray resonators are presented. Owing to the symmetry of the crystals used, the Bragg back reflection usually employed in normal-incidence two- and multi-plate resonators to reflect the X-ray beam is often accompanied by unavoidable multiple-beam diffraction, and thus the reflectivity and cavity finesse are quite low. In contrast, crystal-based Fabry–Perot (FP) resonators at inclined incidence utilize multiple-beam diffraction to excite the back reflection inside the resonator to generate FP resonance with high efficiency, while avoiding the incident beam suffering from crystal absorption. The useful characteristics of inclined-incidence resonators are derived from numerical calculations based on the inclined-incidence diffraction geometry and the dynamical theory. Experimental results with Laue inclined incidence are in accordance with the simulation. The sub-millielectronvolt energy resolution and ultra-high efficiency of the transmission spectrum of the proposed resonators are also described.

A polarization-switch effect of silicon crystals under multiple-beam diffraction geometry

2021 ◽  
Vol 54 (3) ◽  
Author(s):  
Zheng Tang ◽  
Lirong Zheng ◽  
Shengqi Chu ◽  
Pengfei An ◽  
Xianrong Huang ◽  
...  
Keyword(s):  
Dynamical Theory ◽  
Destructive Interference ◽  
Polarization Rotation ◽  
Multiple Wave ◽  
X Ray ◽  
Multiple Beam ◽  
Silicon Crystals ◽  
Diffraction Geometry ◽  
Polarization Switch ◽  
Beam Diffraction

On the basis of rigorous dynamical-theory calculations, a complete X-ray polarization-switch effect of silicon crystals at the exact multiple-beam diffraction condition is demonstrated. The underlying physical mechanism of this unique phenomenon can be revealed using a simple multiple-wave propagation and interference model. The constructive and destructive interference of the multiple detoured-diffraction beams along the direction of the primary diffracted beam directly leads to the complete polarization switch. This phenomenon can be realized using both synchrotron and laboratory X-ray sources at many discrete wavelengths, and used to design a novel crystal-based polarizer to achieve a 90° polarization rotation.

Coherent Interaction of Multiple Diffracted X-Rays in Crystals

1982 ◽  
Vol 37 (5) ◽  
pp. 501-504 ◽  
Author(s):  
Shih-Lin Chang
Keyword(s):  
Synchrotron Radiation ◽  
Incident Beam ◽  
Dynamical Theory ◽  
X Rays ◽  
Diffraction Experiment ◽  
Dynamical Interaction ◽  
X Ray ◽  
Coherent Interaction ◽  
Beam Diffraction ◽  
Intensity Spot

Coherent dynamical interaction in a 6-beam Borrmann diffraction experiment leading to an unusual intensity enhancement of X-ray transmission in crystals is investigated by using a synchrotron radiation source. A sharp enhanced intensity spot of two seconds of arc beam- divergence is observe 1 on the direct beam at the exact 6-beam diffraction position. The plane- wave dynamical theory is employed to account for the experimental results. The polarization dependence of the crystal excitation by the incident beam is discussed.

Dynamical effects in the integrated X-ray scattering intensity from imperfect crystals in Bragg diffraction geometry. II. Dynamical theory

2021 ◽  
Vol 77 (5) ◽  
Author(s):  
V. B. Molodkin ◽  
S. I. Olikhovskii ◽  
S. V. Dmitriev ◽  
V. V. Lizunov
Keyword(s):  
Reciprocal Lattice ◽  
Dynamical Theory ◽  
Bragg Diffraction ◽  
Three Dimensions ◽  
X Ray ◽  
X Ray Scattering ◽  
Diffraction Geometry ◽  
Lattice Space ◽  
Integrated Intensities ◽  
Ray Scattering

The analytical expressions for coherent and diffuse components of the integrated reflection coefficient are considered in the case of Bragg diffraction geometry for single crystals containing randomly distributed microdefects. These expressions are analyzed numerically for the cases when the instrumental integration of the diffracted X-ray intensity is performed on one, two or three dimensions in the reciprocal-lattice space. The influence of dynamical effects, i.e. primary extinction and anomalously weak and strong absorption, on the integrated intensities of X-ray scattering is investigated in relation to the crystal structure imperfections.

Study of dislocations in AlN single-crystal using bright-field synchrotron x-ray topography under a multiple-beam diffraction condition

2020 ◽  
Vol 117 (9) ◽  
pp. 092102 ◽  
Author(s):  
Yongzhao Yao ◽  
Yoshiyuki Tsusaka ◽  
Yukari Ishikawa ◽  
Yoshihiro Sugawara ◽  
Yu Fujita ◽  
...  
Keyword(s):  
Single Crystal ◽  
Bright Field ◽  
X Ray ◽  
Multiple Beam ◽  
Beam Diffraction ◽  
Diffraction Condition

Theory of bulk resonance diffraction in THEED

1993 ◽  
Vol 440 (1908) ◽  
pp. 95-115 ◽  
Keyword(s):  
Elastic Scattering ◽  
Incident Beam ◽  
Bloch Wave ◽  
Dynamical Theory ◽  
Zone Axis ◽  
Bloch Waves ◽  
Diffraction Geometry ◽  
Ewald Sphere ◽  
Lattice Images ◽  
New Type

A full dynamical theory has been developed for an off-axis diffraction geometry. A new type of resonance elastic scattering is found and discussed. This occurs when the Ewald sphere is almost tangential to one of the minus high order Laue zones, and is termed bulk resonance diffraction. It is shown that under certain diffraction conditions, i. e. bulk resonance diffraction conditions, effectively only a single distinct tightly bound Bloch wave localized around atom strings is excited within the crystal, and selection can be made of the particular bound Bloch waves by appropriately tilting the incident beam or the crystal. A new scheme for imaging individual tightly bound Bloch waves is proposed. Full dynamical calculations have been made for 1T–V Se 2 single crystals. It is demonstrated that chemical lattice images of V and Se atom strings can be obtained along the [0001] zone axis of a 1T–V Se 2 crystal for angles of incidence of 109.54 and 109.90 mrad respectively.

LauePt, a graphical-user-interface program for simulating and analyzing white-beam X-ray diffraction Laue patterns

2010 ◽  
Vol 43 (4) ◽  
pp. 926-928 ◽  
Author(s):  
X. R. Huang
Keyword(s):  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Crystallography ◽  
White Beam ◽  
Diffraction Geometry ◽  
Wide Range ◽  
User Friendly ◽  
Beam Diffraction ◽  
Laue Method

LauePtis a robust and extremely easy-to-use Windows application for accurately simulating, indexing and analyzing white-beam X-ray diffraction Laue patterns of any crystals under arbitrary diffraction geometry. This program has a user-friendly graphic interface and can be conveniently used by nonspecialists with little X-ray diffraction or crystallography knowledge. Its wide range of applications include (1) determination of single-crystal orientation with the Laue method, (2) white-beam topography, (3) white-beam microdiffraction, (4) X-ray studies of twinning, domains and heterostructures, (5) verification or determination of crystal structures from white-beam diffraction, and (6) teaching of X-ray crystallography.

Dynamical effects in the integrated X-ray scattering intensity from imperfect crystals in Bragg diffraction geometry. I. Semi-dynamical model

2020 ◽  
Vol 76 (1) ◽  
pp. 45-54
Author(s):  
V. B. Molodkin ◽  
S. I. Olikhovskii ◽  
S. V. Dmitriev ◽  
A. I. Nizkova ◽  
V. V. Lizunov
Keyword(s):  
Silicon Crystal ◽  
Azimuthal Angle ◽  
Dynamical Theory ◽  
Bragg Diffraction ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Diffraction Geometry ◽  
Coulomb Type ◽  
Analytical Expressions

The analytical expressions for the coherent and diffuse components of the integrated reflection coefficient are considered in the case of asymmetric Bragg diffraction geometry for a single crystal of arbitrary thickness, which contains randomly distributed Coulomb-type defects. The possibility to choose the combinations of diffraction conditions optimal for characterizing defects of several types by accounting for dynamical effects in the integrated coherent and diffuse scattering intensities, i.e. primary extinction and anomalous absorption, has been analysed based on the statistical dynamical theory of X-ray diffraction by imperfect crystals. The measured integrated reflectivity dependencies of the imperfect silicon crystal on azimuthal angle were fitted to determine the diffraction parameters characterizing defects in the sample using the proposed formulas in semi-dynamical and semi-kinematical approaches.

Theory of moiré fringes on X-ray diffraction topographs of bicrystals

1999 ◽  
Vol 55 (3) ◽  
pp. 413-422 ◽  
Author(s):  
Michael Ohler ◽  
Jürgen Härtwig
Keyword(s):  
Optical Properties ◽  
Dynamical Theory ◽  
Perfect Crystal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Moiré Fringes ◽  
Diffraction Geometry

The theory of moiré fringes on X-ray diffraction topographs of bicrystals is derived from the dynamical theory of X-ray diffraction for the reflection (Bragg) and the transmission (Laue) case. The influence on the moiré fringes of the diffraction geometry, of the geometry of the sample, of its optical properties and of the topographic method is investigated. The perfect-crystal theory is also expanded to weakly deformed bicrystals.

Imaging of the helical arrangement of cellulose fibrils in wood by synchrotron X-ray microdiffraction

1999 ◽  
Vol 32 (6) ◽  
pp. 1127-1133 ◽  
Author(s):  
H. Lichtenegger ◽  
M. Müller ◽  
O. Paris ◽  
Ch. Riekel ◽  
P. Fratzl
Keyword(s):  
Incident Beam ◽  
Special Choice ◽  
Local Orientation ◽  
Cell Axis ◽  
Beam Position ◽  
X Ray ◽  
Diffraction Geometry ◽  
Ewald Sphere ◽  
Cellulose Fibrils ◽  
Diffraction Patterns

A complete image of the helical arrangement of cellulose fibrils in the S2 layer of adjacent wood cells ofPicea abies(Norwegian spruce) was obtained by applying position-resolved synchrotron X-ray microdiffraction on cells in cross section. In contrast to conventional fiber diffraction studies, the incident beam was parallel to the longitudinal cell axis, resulting in a glancing angle μ far from 90° with respect to the cellulose fibrils. This special choice of diffraction geometry allowed us to take advantage of an asymmetry effect in the two-dimensional diffraction patterns arising from the curvature of the Ewald sphere to obtain information on the local orientation of the cellulose fibrils. The small size of the beam, smaller than the thickness of a single cell wall, allowed mesh scans over intact transverse sections of adjacent wood cells with a microscopic position resolution. The scan yielded a map of diffraction patterns that could readily serve as a microscopic image. Each of the diffraction patterns was then used to evaluate the local orientation of the cellulose fibrils at the actual beam position. The combination of these results gave an image of cellulose fibrils forming (Z) helices in several adjacent wood cells.

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