Characterization and on-line adjustment of the sagittal-bent Laue crystal profile

2018 ◽  
Vol 25 (5) ◽  
pp. 1346-1353
Author(s):  
Weiwei Dong ◽  
Quan Cai ◽  
Fugui Yang ◽  
Xu Liu ◽  
Jiaowang Yang ◽  
...  
Keyword(s):  
Ray Tracing ◽  
Crystal Surface ◽  
Great Influence ◽  
High Energy ◽  
Double Crystal ◽  
X Ray ◽  
Bent Crystal ◽  
On Line ◽  
Condition Adjustment ◽  
Anticlastic Curvature

The sagittal-bent Laue monochromator can provide an ideal way to focus high-energy X-ray beams. However, the anticlastic curvature induced by sagittal bending has a great influence on the crystal performance. Thus, characterizing the bent-crystal shape is very important for predicting the performance of the bent-crystal monochromator. In this paper the crystal profile is measured by off-line optical metrology and on-line X-ray experiments. The off-line results showed that the bent-crystal surface could be well fitted to a saddle surface apart from a redundant cubic term which was related to the different couples applied on the crystal. On-line characterization of the meridional and the sagittal radius of the bent crystal includes double-crystal topography and ray-tracing measurement. In addition, the double-crystal topography experiment could be used as a quick diagnostic method for the bending condition adjustment. The sagittal radius of the bent crystal was characterized through a ray-tracing experiment by using a particularly designed tungsten mask. Moreover, rocking curves under different bending conditions were measured as well. The results were highly consistent with analytical results derived from the elastic theory. Furthermore, radii along different vertical positions under various bending conditions were measured and showed a quadratic relationship between the vertical positions and the meridional radii.

scholarly journals Highly efficient, easily spectrally tunable X-ray backlighting for the study of extreme matter states

2009 ◽  
Vol 27 (4) ◽  
pp. 601-609 ◽  
Author(s):  
B. Loupias ◽  
F. Perez ◽  
A. Benuzzi-Mounaix ◽  
N. Ozaki ◽  
M. Rabec ◽  
...  
Keyword(s):  
Energy Density ◽  
Ray Tracing ◽  
Spatial Resolution ◽  
Normal Incidence ◽  
High Energy ◽  
High Energy Density ◽  
High Luminosity ◽  
X Ray ◽  
High Energy Density Physics ◽  
Bent Crystal

AbstractAn improved high luminosity, easily spectrally tunable backlighting scheme based on a spherically bent crystal is considered in this paper. Contrary to the traditional backlighting scheme, we used crystal far from normal incidence, and the backlighter source was inside the Rowland circle. With the presented configuration, we obtained a spatial resolution up to 8 µm in the desired direction with an X-ray backlighting energy close to 5 keV. Detailed discussions and ray-tracing calculations show that with this convenient scheme resolution down to 5 µm can be achieved. A dedicated application to high energy density physics is presented: the radiography of shock compressed matter.

Sagittal focusing of high-energy synchrotron X-rays with asymmetric Laue crystals. II. Experimental studies

2001 ◽  
Vol 34 (5) ◽  
pp. 646-653 ◽  
Author(s):  
Z. Zhong ◽  
C. C. Kao ◽  
D. P. Siddons ◽  
J. B. Hastings
Keyword(s):  
Focal Length ◽  
Experimental Studies ◽  
High Energy ◽  
X Rays ◽  
Horizontal Position ◽  
Double Crystal ◽  
X Ray ◽  
Bent Crystal ◽  
Planar Crystal ◽  
Diffraction Angle

The use of bent asymmetric Laue crystals to focus synchrotron X-rays sagittally from 15 to 50 keV is described. A four-bar bender, bending a rectangular planar crystal, produced the necessary sagittal and meridional bending for this unique application. Adjustments of the tilt angle and height of the bent crystal resulted in first- and second-order corrections, respectively, to the dependence of the angle of diffraction on the horizontal position on the crystal. After these corrections, the remaining variation of the diffraction angle was of the order of 10 µrad. The theoretical sagittal focal length was verified. A prototype of a double-crystal sagittally focusing monochromator was constructed and tested, using two identical Laue crystals. A horizontal divergence of 3 mrad was focused to a horizontal dimension of about 0.4 mm. The X-ray flux density at the focus was a few hundred times larger than that of unfocused X-rays.

Investigation on Large-Sized Sapphire Crystalline Perfection by X-Ray Double-Crystal Diffraction Method

2007 ◽  
Vol 353-358 ◽  
pp. 1521-1524 ◽  
Author(s):  
Gui Gen Wang ◽  
Ming Fu Zhang ◽  
Hong Bo Zuo ◽  
Xiao Dong He ◽  
Jie Cai Han ◽  
...  
Keyword(s):  
Simulation Analysis ◽  
Crystal Surface ◽  
Diffraction Method ◽  
Sapphire Crystal ◽  
Crystalline Perfection ◽  
Double Crystal ◽  
X Ray ◽  
Infrared Spectral ◽  
Growth Method ◽  
Small Temperature Gradient

The large-sized sapphire (Ø225×205 mm, 27.5 kg) was grown successfully by SAPMAC method (sapphire growth technique with micro-pulling and shoulder-expanding at cooled center). The surface quality of the specimens was characterized by micro-Raman spectroscopy, and double crystal X-ray diffractometry (DCD) was utilized to investigate its crystalline perfection. The measurement of rocking curves was performed on various specimens from different region of large sapphire boule. The experimental results showed that CMP (chemo-mechanical polishing) with subsequent suitable chemically etching can develop the best-quality sapphire crystal surface and the values of FWHM obtained by conventional DCD were in the range from 27” to 58”. The infrared spectral transmission (2.0-4.5 5m) of sapphire crystal exceeded 82%. It is confirmed of SAPMAC growth method characteristics with in-situ annealing, small temperature gradient and low residual stress level by numerical simulation analysis.

scholarly journals Performance of bent-crystal x-ray microscopes for high energy density physics research

2015 ◽  
Vol 54 (16) ◽  
pp. 5147 ◽  
Author(s):  
Marius S. Schollmeier ◽  
Matthias Geissel ◽  
Jonathon E. Shores ◽  
Ian C. Smith ◽  
John L. Porter
Keyword(s):  
Energy Density ◽  
High Energy ◽  
High Energy Density ◽  
X Ray ◽  
High Energy Density Physics ◽  
Bent Crystal

Dislocations Nucleating Growth in Liquid Phase Epitaxy of Gallium Arsenide

1993 ◽  
Vol 312 ◽  
Author(s):  
Werner Möhling ◽  
H. Weishart ◽  
E. Bauser
Keyword(s):  
Gallium Arsenide ◽  
Liquid Phase ◽  
Liquid Phase Epitaxy ◽  
Crystal Surface ◽  
Double Crystal ◽  
Growth Interface ◽  
Growth Step ◽  
Burgers Vector ◽  
X Ray ◽  
Back Reflection

AbstractDislocations in GaAs are analysed by X-ray topography in order to relate their nature to their efficiency in generating growth steps. The analysis is mainly based on comparing double crystal back reflection images of the defects to calculated misorientations of the crystal surface which are caused at the outcrop. All types of dislocations are equally effective provided their Burgers vector has a component normal to the growth interface. Concentric growth step patterns, which develop in varying numbers on different samples are not caused by substrate dislocations.

scholarly journals Ray-tracing simulations of a bent crystal X-ray optics for imaging using laser–plasma X-ray sources

2004 ◽  
Vol 22 (3) ◽  
pp. 253-259 ◽  
Author(s):  
L. LABATE ◽  
M. GALIMBERTI ◽  
A. GIULIETTI ◽  
D. GIULIETTI ◽  
L.A. GIZZI ◽  
...  
Keyword(s):  
Ray Tracing ◽  
Spatial Resolution ◽  
Laser Plasma ◽  
Imaging System ◽  
Complex Pattern ◽  
Careful Study ◽  
Ray Optics ◽  
X Ray ◽  
Bent Crystal ◽  
Laser Produced Plasma

Ray-tracing simulations of an optical X-ray system based on a spherically bent crystal operating in Bragg configuration for monochromatic projection imaging of thin samples are presented, obtained using a code developed for that purpose. The code is particularly suited for characterizing experimental arrangements routinely used with laser-produced plasma X-ray sources. In particular, the spatial resolution of the imaging system was investigated and a careful study of the complex pattern of the X-ray backlighting beam was performed.

HAXPES beamline PES-BL14 at the Indus-2 synchrotron radiation source

2018 ◽  
Vol 25 (5) ◽  
pp. 1541-1547 ◽  
Author(s):  
Jagannath ◽  
U. K. Goutam ◽  
R. K. Sharma ◽  
J. Singh ◽  
K. Dutta ◽  
...  
Keyword(s):  
Thin Film ◽  
High Resolution ◽  
Electron Spectroscopy ◽  
High Energy ◽  
Solid Samples ◽  
Double Crystal ◽  
X Ray ◽  
Double Crystal Monochromator ◽  
Ccd Detector ◽  
Scientific Results

The Hard X-ray Photo-Electron Spectroscopy (HAXPES) beamline (PES-BL14), installed at the 1.5 T bending-magnet port at the Indian synchrotron (Indus-2), is now available to users. The beamline can be used for X-ray photo-emission electron spectroscopy measurements on solid samples. The PES beamline has an excitation energy range from 3 keV to 15 keV for increased bulk sensitivity. An in-house-developed double-crystal monochromator [Si (111)] and a platinum-coated X-ray mirror are used for the beam monochromatization and manipulation, respectively. This beamline is equipped with a high-energy (up to 15 keV) high-resolution (meV) hemispherical analyzer with a microchannel plate and CCD detector system with SpecsLab Prodigy and CasaXPS software. Additional user facilities include a thin-film laboratory for sample preparation and a workstation for on-site data processing. In this article, the design details of the beamline, other facilities and some recent scientific results are described.

scholarly journals High energy-resolution x-ray spectroscopy at ultra-high dilution with spherically bent crystal analyzers of 0.5 m radius

2017 ◽  
Vol 88 (1) ◽  
pp. 013108 ◽  
Author(s):  
Mauro Rovezzi ◽  
Christophe Lapras ◽  
Alain Manceau ◽  
Pieter Glatzel ◽  
Roberto Verbeni
Keyword(s):  
Energy Resolution ◽  
High Energy ◽  
High Energy Resolution ◽  
High Dilution ◽  
X Ray ◽  
Bent Crystal

A Johann-type X-ray emission spectrometer at the Rossendorf beamline

2016 ◽  
Vol 23 (3) ◽  
pp. 836-841 ◽  
Author(s):  
Kristina O. Kvashnina ◽  
Andreas C. Scheinost
Keyword(s):  
Atmospheric Pressure ◽  
Environmental Samples ◽  
Avalanche Photodiode ◽  
High Energy ◽  
European Synchrotron Radiation Facility ◽  
High Energy Resolution ◽  
X Ray ◽  
Bent Crystal ◽  
Crystal Analyzer ◽  
X Ray Absorption

This paper gives a detailed description, including equations, of the Johann-type X-ray emission spectrometer which has been recently installed and tested at the Rossendorf beamline (ROBL) of the European Synchrotron Radiation Facility. The spectrometer consists of a single spherically bent crystal analyzer and an avalanche photodiode detector positioned on the vertical Rowland cycle of 1 m diameter. The hard X-ray emission spectrometer (∼3.5–25 keV) operates at atmospheric pressure and covers the Bragg angles of 65°–89°. The instrument has been tested at high and intermediate incident energies,i.e.at the ZrK-edge and at the AuL3-edge, in the second experimental hutch of ROBL. The spectrometer is dedicated for studying actinides in materials and environmental samples by high-energy-resolution X-ray absorption and X-ray emission spectroscopies.

IN SITU STUDIES OF EPITAXIAL GROWTH BY SYNCHROTRON X-RAY DIFFRACTION

2006 ◽  
Vol 13 (02n03) ◽  
pp. 155-166 ◽  
Author(s):  
WOLFGANG BRAUN ◽  
KLAUS H. PLOOG
Keyword(s):  
Ostwald Ripening ◽  
Crystal Surface ◽  
High Energy ◽  
Molecular Beam Epitaxy Growth ◽  
X Rays ◽  
Surface Kinetics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Kinetics Of

X-rays are ideal to study the structure of crystals due to their weak interaction with matter and in most cases allow a quantitative analysis using kinematical theory. To study the incorporation of atoms during crystal growth and to analyze the kinetics on the crystal surface high primary beam intensities available at synchrotrons are required. Our studies of the molecular beam epitaxy growth of III–V semiconductors reveal that, despite their similarity in crystal structure, the surface kinetics of GaAs (001), InAs (001) and GaSb (001) differ strongly. GaAs shows an unexpectedly large coarsening exponent outside the predicted range of Ostwald ripening models during recovery. GaSb exhibits dramatically different surface morphology variations during growth and recovery. Overgrowth of GaAs by epitaxial MnAs demonstrates the ability of X-ray diffraction to follow an interface as it is buried during heteroepitaxy, which is not possible by reflection high-energy electron diffraction.

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