High diffraction efficiency in crystals curved by surface damage

2013 ◽  
Vol 46 (6) ◽  
pp. 1576-1581 ◽  
Author(s):  
Claudio Ferrari ◽  
Elisa Buffagni ◽  
Elisa Bonnini ◽  
Dusan Korytar
Keyword(s):  
Surface Damage ◽  
Curvature Radius ◽  
Optical Elements ◽  
X Ray ◽  
Integrated Intensity ◽  
Damage Process ◽  
Extinction Length ◽  
Lattice Planes ◽  
Bent Crystals ◽  
Strong Curvature

Diffraction profiles of curved Si and GaAs crystals obtained by a controlled damage process on one side of planar crystals have been investigated at X-ray energiesE= 17, 59 and 120 keV. AtE= 17 and 59 keV in the condition of slight curvature, that is when the diffracting plane bending over the extinction length is lower than the Darwin width, the Laue diffraction profiles with lattice planes parallel or inclined with respect to the curvature radiusRshow an enhancement of integrated intensity proportional to 1/R, much larger than in the corresponding perfect bent crystals. AtE= 120 keV, in the condition of strong curvature, the crystals behave as bent perfect crystals with integrated intensity corresponding to that of a mosaic crystal. These crystals are proposed as optical elements for focusing hard X-ray beams.

Preparation of bent crystals as high-efficiency optical elements for hard x-ray astronomy

2011 ◽  
Author(s):  
Elisa Buffagni ◽  
Claudio Ferrari ◽  
Francesca Rossi ◽  
Laura Marchini ◽  
Andrea Zappettini
Keyword(s):  
High Efficiency ◽  
Optical Elements ◽  
X Ray ◽  
Bent Crystals

scholarly journals X-ray diffraction from strongly bent crystals and spectroscopy of X-ray free-electron laser pulses

2020 ◽  
Vol 76 (1) ◽  
pp. 55-69 ◽  
Author(s):  
Vladimir M. Kaganer ◽  
Ilia Petrov ◽  
Liubov Samoylova
Keyword(s):  
Free Electron ◽  
Free Electron Laser ◽  
Laser Pulses ◽  
Crystal Thickness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bending Radius ◽  
Extinction Length ◽  
Bent Crystals ◽  
Better Than

The use of strongly bent crystals in spectrometers for pulses of a hard X-ray free-electron laser is explored theoretically. Diffraction is calculated in both dynamical and kinematical theories. It is shown that diffraction can be treated kinematically when the bending radius is small compared with the critical radius given by the ratio of the Bragg-case extinction length for the actual reflection to the Darwin width of this reflection. As a result, the spectral resolution is limited by the crystal thickness, rather than the extinction length, and can become better than the resolution of a planar dynamically diffracting crystal. As an example, it is demonstrated that spectra of the 12 keV pulses can be resolved in the 440 reflection from a 20 µm-thick diamond crystal bent to a radius of 10 cm.

scholarly journals General method to calculate the elastic deformation and X-ray diffraction properties of bent crystal wafers

IUCrJ ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 102-115
Author(s):  
Ari-Pekka Honkanen ◽  
Simo Huotari
Keyword(s):  
Stress And Strain ◽  
Light Sources ◽  
X Ray Diffraction ◽  
Optical Elements ◽  
Theoretical Understanding ◽  
Strain Fields ◽  
X Ray ◽  
Bent Crystal ◽  
Bent Crystals ◽  
General Method

Toroidally and spherically bent single crystals are widely employed as optical elements in hard X-ray spectrometry at synchrotron and free-electron laser light sources, and in laboratory-scale instruments. To achieve optimal spectrometer performance, a solid theoretical understanding of the diffraction properties of such crystals is essential. In this work, a general method to calculate the internal stress and strain fields of toroidally bent crystals and how to apply it to predict their diffraction properties is presented. Solutions are derived and discussed for circular and rectangular spherically bent wafers due to their prevalence in contemporary instrumentation.

scholarly journals Correction factors in the photographic measurements of x-ray intensities in crystal analysis

1930 ◽  
Vol 127 (804) ◽  
pp. 71-88 ◽  
Keyword(s):  
Background Radiation ◽  
Complete Solution ◽  
Special Technique ◽  
X Rays ◽  
X Ray ◽  
Intensity Measurements ◽  
Integrated Intensity ◽  
Lattice Planes ◽  
Complex Crystals ◽  
Lengthy Operation

For the complete solution of the structures of complex crystals, and in particular of organic substances, it is essential to be able to measure at least the relative intensities of reflexion of homogeneous X-rays from the more important lattice planes with some degree of accuracy. In most crystal problems a number of parameters governing the positions of the atoms in the lattice remain to be found after the geometrical requirements of the symmetry have been satisfied. These can only be determined from intensity measurements, so that in general, the greater the number of reflexions measured, the more closely will the deduced structure approach to the truth. Until comparatively recently the only instrument of precision available for X-ray intensity work has been the Bragg ionisation spectrometer. It has, however, three disadvantages when used for this purpose, which may be briefly summarised:— (1) Only the strongest planes are measurable with any degree of accuracy, owing to the “swamping” effect of the unremovable background radiation in the case of the weaker reflexions. (2) It is clearly impossible to use it, without very special technique, in the case of crystals which are volatile or even liquid at normal temperatures. (3) The measurement of the true integrated intensity is a somewhat lengthy operation in practice, with the result that experimenters are tempted to determine the peak values of the intensities instead; these, in general, are not in the same ratio as the integrated reflexions, so that a false idea of the reflexions may be obtained.

Automatic measurement of SAED patterns from asbestos minerals

1988 ◽  
Vol 46 ◽  
pp. 846-847
Author(s):  
J. C. Russ ◽  
T. Taguchi ◽  
P. M. Peters ◽  
E. Chatfield ◽  
J. C. Russ ◽  
...  
Keyword(s):  
Diffraction Pattern ◽  
High Precision ◽  
Diffraction Data ◽  
Automatic Measurement ◽  
Automatic Method ◽  
Important Method ◽  
X Ray ◽  
Integrated Intensity ◽  
Asbestiform Minerals ◽  
True Center

Conventional SAD patterns as obtained in the TEM present difficulties for identification of materials such as asbestiform minerals, although diffraction data is considered to be an important method for making this purpose. The preferred orientation of the fibers and the spotty patterns that are obtained do not readily lend themselves to measurement of the integrated intensity values for each d-spacing, and even the d-spacings may be hard to determine precisely because the true center location for the broken rings requires estimation. We have implemented an automatic method for diffraction pattern measurement to overcome these problems. It automatically locates the center of patterns with high precision, measures the radius of each ring of spots in the pattern, and integrates the density of spots in that ring. The resulting spectrum of intensity vs. radius is then used just as a conventional X-ray diffractometer scan would be, to locate peaks and produce a list of d,I values suitable for search/match comparison to known or expected phases.

Electromagnetic-matter interactions and devices

2017 ◽  
Author(s):  
Sandip Tiwari
Keyword(s):  
Optical Tweezers ◽  
Quantum Cascade Lasers ◽  
Accelerator Physics ◽  
X Ray ◽  
Quantum Cascade ◽  
Inorganic Systems ◽  
Charge Cloud ◽  
Atomic Distance ◽  
Extinction Length ◽  
Cascade Lasers

This chapter explores electromagnetic-matter interactions from photon to extinction length scales, i.e., nanometer of X-ray and above. Starting with Casimir-Polder effect to understand interactions of metals and dielectrics at near-atomic distance scale, it stretches to larger wavelengths to explore optomechanics and its ability for energy exchange and signal transduction between PHz and GHz. This range is explored with near-quantum sensitivity limits. The chapter also develops the understanding phononic bandgaps, and for photons, it explores the use of energetic coupling for useful devices such as optical tweezers, confocal microscopes and atomic clocks. It also explores miniature accelerators as a frontier area in accelerator physics. Plasmonics—the electromagnetic interaction with electron charge cloud—is explored for propagating and confined conditions together with the approaches’ possible uses. Optoelectronic energy conversion is analyzed in organic and inorganic systems, with their underlying interaction physics through solar cells and its thermodynamic limit, and quantum cascade lasers.

scholarly journals Structural and Enhanced Optical Properties of Stabilized γ‒Bi2O3 Nanoparticles: Effect of Oxygen Ion Vacancies

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1023 ◽  
Author(s):  
Ashish Chhaganlal Gandhi ◽  
Chia-Liang Cheng ◽  
Sheng Yun Wu
Keyword(s):  
Room Temperature ◽  
Excess Oxygen ◽  
Ambient Atmosphere ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Band Emission ◽  
Oxygen Ion ◽  
Integrated Intensity ◽  
Effect Of Oxygen

We report the synthesis of room temperature (RT) stabilized γ–Bi2O3 nanoparticles (NPs) at the expense of metallic Bi NPs through annealing in an ambient atmosphere. RT stability of the metastable γ–Bi2O3 NPs is confirmed using synchrotron radiation powder X-ray diffraction and Raman spectroscopy. γ–Bi2O3 NPs exhibited a strong red-band emission peaking at ~701 nm, covering 81% integrated intensity of photoluminescence spectra. Our findings suggest that the RT stabilization and enhanced red-band emission of γ‒Bi2O3 is mediated by excess oxygen ion vacancies generated at the octahedral O(2) sites during the annealing process.

scholarly journals Simultaneous Multi-Bragg Peak Coherent X-ray Diffraction Imaging

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 312
Author(s):  
Florian Lauraux ◽  
Stéphane Labat ◽  
Sarah Yehya ◽  
Marie-Ingrid Richard ◽  
Steven J. Leake ◽  
...  
Keyword(s):  
Bragg Reflection ◽  
Volume Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystal Substrate ◽  
In Series ◽  
Diffraction Imaging ◽  
Diffraction Patterns ◽  
Lattice Planes ◽  
Oriented Parallel

The simultaneous measurement of two Bragg reflections by Bragg coherent X-ray diffraction is demonstrated on a twinned Au crystal, which was prepared by the solid-state dewetting of a 30 nm thin gold film on a sapphire substrate. The crystal was oriented on a goniometer so that two lattice planes fulfill the Bragg condition at the same time. The Au 111 and Au 200 Bragg peaks were measured simultaneously by scanning the energy of the incident X-ray beam and recording the diffraction patterns with two two-dimensional detectors. While the former Bragg reflection is not sensitive to the twin boundary, which is oriented parallel to the crystal–substrate interface, the latter reflection is only sensitive to one part of the crystal. The volume ratio between the two parts of the twinned crystal is about 1:9, which is also confirmed by Laue microdiffraction of the same crystal. The parallel measurement of multiple Bragg reflections is essential for future in situ and operando studies, which are so far limited to either a single Bragg reflection or several in series, to facilitate the precise monitoring of both the strain field and defects during the application of external stimuli.

scholarly journals X-ray imaging of silicon die within fully packaged semiconductor devices

2021 ◽  
pp. 1-7
Author(s):  
Brian K. Tanner ◽  
Patrick J. McNally ◽  
Andreas N. Danilewsky
Keyword(s):  
Synchrotron Radiation ◽  
Feasibility Studies ◽  
Monochromatic Radiation ◽  
X Ray Diffraction ◽  
Divergent Beam ◽  
X Ray ◽  
X Ray Imaging ◽  
Setting Process ◽  
Diffraction Imaging ◽  
Lattice Planes

X-ray diffraction imaging (XRDI) (topography) measurements of silicon die warpage within fully packaged commercial quad-flat no-lead devices are described. Using synchrotron radiation, it has been shown that the tilt of the lattice planes in the Analog Devices AD9253 die initially falls, but after 100 °C, it rises again. The twist across the die wafer falls linearly with an increase in temperature. At 200 °C, the tilt varies approximately linearly with position, that is, displacement varies quadratically along the die. The warpage is approximately reversible on cooling, suggesting that it has a simple paraboloidal form prior to encapsulation; the complex tilt and twisting result from the polymer setting process. Feasibility studies are reported, which demonstrate that a divergent beam and quasi-monochromatic radiation from a sealed X-ray tube can be used to perform warpage measurements by XRDI in the laboratory. Existing tools have limitations because of the geometry of the X-ray optics, resulting in applicability only to simple warpage structures. The necessary modifications required for use in situations of complex warpage, for example, in multiple die interconnected packages are specified.

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