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.

Micro-X-Ray Fluorescence Analysis on a Synchrotron Radiation Wiggler Beam Line

1991 ◽  
Vol 35 (B) ◽  
pp. 995-1000
Author(s):  
J.V. Gilfrich ◽  
E.F. Skelton ◽  
S.B. Qadri ◽  
N.E. Moulton ◽  
D.J. Nagel ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
National Laboratory ◽  
Incident Beam ◽  
Fluorescence Analysis ◽  
High Energy ◽  
Brookhaven National Laboratory ◽  
Beam Line ◽  
X Rays ◽  
X Ray ◽  
Electron Orbit

AbstractIt has been well established over recent years that synchrotron radiation possesses some unique features as a source of primary x-rays for x-ray fluorescence analysis. Advantage has been taken of the high intensity emanating from the bending magnets of storage rings to develop x-ray microprobes utilizing apertures or focussing optics, or both, to provide a beam spot at the specimen of the order of micrometers. The use of insertion devices wigglers and undulatora, can further increase the available intensity, especially for the high energy photons. Beam Line X-17C at the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory, accepts the unmodified continuum radiation from a superconducting wiggler in the storage ring. Some initial XRF measurements have been made on this beam line using apertures in the 10 to 100 micrometer range. The fluorescent radiation was measured by an intrinsic Ge detector having an energy resolution of 300 eV at 15 kev, and located at 90° to the incident beam in the plane of the electron orbit. In samples containing many elements, detection limits of a few ppm were achieved with 100 μm beams.

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.

Investigation of the phase shift in X-ray forward diffraction using an X-ray interferometer

1998 ◽  
Vol 5 (3) ◽  
pp. 967-968 ◽  
Author(s):  
Keiichi Hirano ◽  
Atsushi Momose
Keyword(s):  
Phase Shift ◽  
Silicon Crystal ◽  
Dynamical Theory ◽  
Perfect Crystal ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bragg Geometry

The phase shift of forward-diffracted X-rays by a perfect crystal is discussed on the basis of the dynamical theory of X-ray diffraction. By means of a triple Laue-case X-ray interferometer, the phase shift of forward-diffracted X-rays by a silicon crystal in the Bragg geometry was investigated.

Applications of High-Resolution Powder X-Ray Diffraction

2007 ◽  
Vol 130 ◽  
pp. 7-14 ◽  
Author(s):  
Andrew N. Fitch
Keyword(s):  
High Resolution ◽  
Synchrotron Radiation ◽  
Powder Diffraction ◽  
X Rays ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
X Ray ◽  
Structural Characterisation ◽  
Pdf Analysis

The highly-collimated, intense X-rays produced by a synchrotron radiation source can be harnessed to build high-resolution powder diffraction instruments with a wide variety of applications. The general advantages of using synchrotron radiation for powder diffraction are discussed and illustrated with reference to the structural characterisation of crystalline materials, atomic PDF analysis, in-situ and high-throughput studies where the structure is evolving between successive scans, and the measurement of residual strain in engineering components.

An algorithm for calculating diffraction profiles of 2θ scans for multiple diffraction from crystals and thin films

2014 ◽  
Vol 70 (6) ◽  
pp. 572-582
Author(s):  
Hsin-Yi Chen ◽  
Mau-Sen Chiu ◽  
Chia-Hung Chu ◽  
Shih-Lin Chang
Keyword(s):  
Initial Phase ◽  
Atomic Layer ◽  
Dynamical Theory ◽  
Far Field ◽  
X Rays ◽  
X Ray Diffraction ◽  
Multiple Diffraction ◽  
X Ray ◽  
Beam Surface ◽  
Surface Diffraction

An algorithm is developed based on the dynamical theory of X-ray diffraction for calculating the profiles of the diffracted beam,i.e.the diagrams of the intensity distributionversus2θ when a crystal is fixed at an angle of its maximum diffracted intensity. Similar to Fraunhofer (far-field) diffraction for a single-slit case, in the proposed algorithm the diffracted beam from one atomic layer excited by X-rays is described by the composition of (N+ 1) coherent point oscillators in the crystal. The amplitude and the initial phase of the electric field for each oscillator can be calculated based on the dynamical theory with given boundary conditions. This algorithm not only gives diffraction profiles but also provides the contribution of the excitation of modes when extremely asymmetric diffraction is involved in the diffraction process. Examples such as extremely asymmetric two-beam surface diffraction and three-beam surface diffraction are presented and discussed in detail.

Residual Stress Measurement around the Interface of Copper Bicrystal Deformed by Uniaxial Extension

2010 ◽  
Vol 64 ◽  
pp. 125-134
Author(s):  
Hanabusa Takao ◽  
Ayumi Shiro ◽  
Tatsuya Okada
Keyword(s):  
Residual Stress ◽  
Synchrotron Radiation ◽  
Grain Boundary ◽  
Residual Stresses ◽  
Uniaxial Extension ◽  
Kink Band ◽  
X Rays ◽  
X Ray ◽  
Kink Bands ◽  
Crystal Orientations

Residual stresses of a copper bicrystal were measured by X-ray diffraction and synchrotron radiation. A copper bicrystal specimen with a 90-degree tilt boundary was fabricated by the Brigdman technique. After the plastic extension of 30%, kink bands developed in a deformed matrix along the grain boundary. In this study, we focused on the residual stress distribution along the transverse direction of the specimen surface and the residual stresses in deformed matrix and kink band near the grain boundary. Residual stresses were evaluated by the X-ray single crystal measurement method. Stereographic projections were used to determine crystal orientations of deformed regions. It was found that crystal orientations were different between the deformed matrix and the kink band. Residual stresses in the direction along the grain boundary were compressive in the vicinity of the boundary and tensile in the region apart from the boundary. Residual stresses in the kink band were large in compression in compared with those in the deformation matrix. The difference in the results between X-rays and synchrotron radiation suggests that there is a depth variation in the deformation and therefore the residual stress development.

scholarly journals Experimentally obtained and computer-simulated X-ray non-coplanar 18-beam pinhole topographs for a silicon crystal

2019 ◽  
Vol 75 (3) ◽  
pp. 483-488 ◽  
Author(s):  
Kouhei Okitsu ◽  
Yasuhiko Imai ◽  
Yoshitaka Yoda
Keyword(s):  
Silicon Crystal ◽  
Dynamical Theory ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Good Agreement

Non-coplanar 18-beam X-ray pinhole topographs for a silicon crystal were computer simulated by fast Fourier transforming the X-ray rocking amplitudes that were obtained by solving the n-beam (n = 18) Ewald–Laue dynamical theory (E-L&FFT method). They were in good agreement with the experimentally obtained images captured using synchrotron X-rays. From this result and further consideration based on it, it has been clarified that the X-ray diffraction intensities when n X-ray waves are simultaneously strong in the crystal can be computed for any n by using the E-L&FFT method.

scholarly journals Synchrotron radiation X-ray tomographic microscopy (SRXTM) of brachiopod shell interiors for taxonomy: Preliminary report

2010 ◽  
pp. 109-117 ◽  
Author(s):  
Neda Motchurova-Dekova ◽  
David Harper
Keyword(s):  
Synchrotron Radiation ◽  
Three Dimensional ◽  
X Rays ◽  
X Ray ◽  
Fine Grained ◽  
Internal Structures ◽  
Efficient Alternative ◽  
Micro Tomography ◽  
Light Beams ◽  
Non Destructive

Synchrotron radiation X-ray tomographic microscopy (SRXTM) is a non-destructive technique for the investigation and visualization of the internal features of solid opaque objects, which allows reconstruction of a complete three-dimensional image of internal structures by recording of the differences in the effects on the passage of waves of energy reacting with those structures. Contrary to X-rays, produced in a conventional X-ray tube, the intense synchrotron light beams are sharply focused like a laser beam. We report encouraging results from the use of SRXTM for purely taxonomic purposes in brachiopods: an attempt to find a non-destructive and more efficient alternative to serial sectioning and several other methods of dissection together with the non-destructive method of X-ray computerised micro-tomography. Two brachiopod samples were investigated using SRXTM. In ?Rhynchonella? flustracea it was possible to visualise the 3D shape of the crura and dental plates. In Terebratulina imbricata it was possible to reveal the form of the brachidium. It is encouraging that we have obtained such promising results using SRXTM with our very first two fortuitous samples, which had respectively fine-grained limestone and marl as infilling sediment, in contrast to the discouraging results communicated to us by some colleagues who have tested specimens with such infillings using X-ray micro-tomography. In future the holotypes, rare museum specimens or delicate Recent material may be preferentially subjected to this mode of analysis.

Accelerator-based X-ray sources: synchrotron radiation, X-ray free electron lasers and beyond

2019 ◽  
Vol 377 (2147) ◽  
pp. 20180231 ◽  
Author(s):  
Tetsuya Ishikawa
Keyword(s):  
Synchrotron Radiation ◽  
Storage Ring ◽  
Free Electron ◽  
Continuous Wave ◽  
Transitional Period ◽  
Light Sources ◽  
X Rays ◽  
Free Electron Lasers ◽  
Beam Emittance ◽  
X Ray

The evolution of synchrotron radiation (SR) sources and related sciences is discussed to explain the ‘generation’ of the SR sources. Most of the contemporary SR sources belong to the third generation, where the storage rings are optimized for the use of undulator radiation. The undulator development allowed to reduction of the electron energy of the storage ring necessary for delivering 10 keV X-rays from the initial 6–8 GeV to the current 3 Gev. Now is the transitional period from the double-bend-achromat lattice-based storage ring to the multi-bend-achromat lattice to achieve much smaller electron beam emittance. Free electron lasers are the other important accelerator-based light sources which recently reached hard X-ray regime by using self-amplified spontaneous emission scheme. Future accelerator-based X-ray sources should be continuous wave X-ray free electron lasers and pulsed X-ray free electron lasers. Some pathways to reach the future case are discussed. This article is part of the theme issue ‘Fifty years of synchrotron science: achievements and opportunities’.

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