scholarly journals Suppressing Diffraction-Related Intensity Losses in Transmissive Single-Crystal X-ray Optics

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1561
Author(s):  
Nataliya Klimova ◽  
Irina Snigireva ◽  
Anatoly Snigirev ◽  
Oleksandr Yefanov
Keyword(s):  
Single Crystal ◽  
Silicon Germanium ◽  
Optical Element ◽  
X Rays ◽  
Ray Optics ◽  
Transmitted Beam ◽  
X Ray ◽  
Diffraction Condition

The highest-quality X-ray optics can be made of single-crystal materials such as silicon, germanium, or, even better, diamond. Unfortunately, such X-ray optics have one drawback: diffraction losses or the “glitch effect”. This effect manifests itself as follows: at some energies of X-rays, the intensity of the transmitted beam drops due to the fact that some crystalline planes have satisfied the diffraction condition. Diffraction losses are usually observed in spectroscopic experiments when the energy of the X-rays changes in a certain range. However, this effect might also influence any experiment using X-rays, especially at higher energies. In this paper, we propose a method to overcome the glitch problem in transmissive optics. This is achieved using small rotations of the optical element. We describe the algorithm for “glitch-free” measurements in detail and the theory behind it.

scholarly journals Lower resolution Laue neutron data yield correct nanocluster formulations

2014 ◽  
Vol 70 (a1) ◽  
pp. C187-C187
Author(s):  
Alison Edwards
Keyword(s):  
Neutron Diffraction ◽  
Single Crystal ◽  
Diffraction Pattern ◽  
Precise Determination ◽  
Data Sets ◽  
X Rays ◽  
Low Resolution ◽  
Neutron Data ◽  
X Ray ◽  
Product Formulation

"The renaissance in Laue studies - at neutron sources - provides us with access to single crystal neutron diffraction data for synthetic compounds without requiring synthesis of prohibitively large amounts of compound or improbably large crystals. Such neutron diffraction studies provide vital data where proof of the presence or absence of hydrogen in particular locations is required and which cannot validly be proved by X-ray studies. Since the commissioning of KOALA at OPAL in 2009[1] we have obtained numerous data sets which demonstrate the vital importance of measuring data even where the extent of the diffraction pattern is at relatively low resolution - especially when compared to that obtainable for the same compound with X-rays. In the Laue experiment performed with a fixed radius detector, data reduction is only feasible for crystals in the ""goldilocks"" zone – where the unit cell is relatively large for the detector, a correspondingly low resolution diffraction pattern in which adjacent spots are less affected by overlap will yield more data against which a structure can be refined than a pattern of higher resolution – one where neighbouring spots overlap rendering both unusable (in our current methodology). Analogous application of powder neutron diffraction in such determinations is also considered. Single crystal neutron diffraction studies of several important compounds (up to 5KDa see figure below)[2] in which precise determination of hydride content by neutron diffraction was pivotal to the final formulation will be presented. The neutron data sets typically possess 20% or fewer unique data at substantially "lower resolution" than the corresponding X-ray data sets. Careful refinement clearly reveals chemical detail which is typically unexplored in related X-ray diffraction studies reporting high profile chemistry despite the synthetic route being one which hydride ought to be considered/excluded in product formulation."

Diamond channel-cut crystals for high-heat-load beam-multiplexing narrow-band X-ray monochromators

2021 ◽  
Vol 28 (6) ◽  
Author(s):  
Yuri Shvyd'ko ◽  
Sergey Terentyev ◽  
Vladimir Blank ◽  
Tomasz Kolodziej
Keyword(s):  
Heat Load ◽  
Narrow Band ◽  
Bragg Reflection ◽  
High Heat ◽  
High Repetition Rate ◽  
X Rays ◽  
Ray Optics ◽  
X Ray ◽  
Load Beam ◽  
High Heat Load

Next-generation high-brilliance X-ray photon sources call for new X-ray optics. Here we demonstrate the possibility of using monolithic diamond channel-cut crystals as high-heat-load beam-multiplexing narrow-band mechanically stable X-ray monochromators with high-power X-ray beams at cutting-edge high-repetition-rate X-ray free-electron laser (XFEL) facilities. The diamond channel-cut crystals fabricated and characterized in these studies are designed as two-bounce Bragg reflection monochromators directing 14.4 or 12.4 keV X-rays within a 15 meV bandwidth to 57Fe or 45Sc nuclear resonant scattering experiments, respectively. The crystal design allows out-of-band X-rays transmitted with minimal losses to alternative simultaneous experiments. Only ≲2% of the incident ∼100 W X-ray beam is absorbed in the 50 µm-thick first diamond crystal reflector, ensuring that the monochromator crystal is highly stable. Other X-ray optics applications of diamond channel-cut crystals are anticipated.

Recent diamond single-crystal x-ray optics developments at the European Synchrotron Radiation Facility

1998 ◽  
Author(s):  
Andreas K. Freund ◽  
Jacques P. Sellschop ◽  
Konrad Lieb ◽  
Sylvain Rony ◽  
Clemens Schulze-Briese ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Single Crystal ◽  
European Synchrotron Radiation Facility ◽  
Diamond Single Crystal ◽  
Ray Optics ◽  
X Ray

A single crystal, linearly polarized Fe 2p X-ray absorption study of gillespite

1998 ◽  
Vol 62 (1) ◽  
pp. 65-75 ◽  
Author(s):  
P. F. Schofield ◽  
G. van der Laan ◽  
C. M. B. Henderson ◽  
G. Cressey
Keyword(s):  
Single Crystal ◽  
Ground State ◽  
Branching Ratio ◽  
Linear Dichroism ◽  
Electronic Charge ◽  
Magic Angle ◽  
X Rays ◽  
X Ray ◽  
Peak Structure ◽  
X Ray Absorption

AbstractThe Fe 2p X-ray absorption spectra of single crystal gillespite, BaFeSi4O10, show a strong linear dichroism, i.e. a large difference in the absorption when measured with the polarization of the X-rays either parallel or perpendicular to the plane of the FeO4 group. The isotropic spectrum, obtained from measurement at the ‘magic angle’, and the polarization dependent spectra have been compared to atomic multiplet calculations and show an excellent agreement with theory. Analysis of the branching ratio, the linear dichroism, and the detailed peak structure confirms that the 5A1 level is the ground state at room temperature and pressure. The 5B2 level is sufficiently low in energy that a distortion of the electronic charge density, induced by increased pressure, may result in a 5B2 ground state.

SURFACE SEGREGATION STUDIES OF SOFC CATHODES: COMBINING SOFT X-RAYS AND ELECTROCHEMICAL IMPEDENCE SPECTROSCOPY

2009 ◽  
Vol 1217 ◽  
Author(s):  
Lincoln Miara ◽  
Louis Piper ◽  
Jacob Nathan Davis ◽  
Laxmikant Saraf ◽  
Tiffany Kaspar ◽  
...  
Keyword(s):  
Single Crystal ◽  
Surface Segregation ◽  
Elevated Temperatures ◽  
Electrochemical Impedance ◽  
Lanthanum Manganite ◽  
X Rays ◽  
Two Phase ◽  
X Ray ◽  
Cation Migration ◽  
X Ray Absorption

AbstractA system to grow heteroepitaxial thin-films of solid oxide fuel cell (SOFC) cathodes on single crystal substrates was developed. The cathode composition investigated was 20% strontium-doped lanthanum manganite (LSM) grown by pulsed laser deposition (PLD) on single crystal (111) yttria-stabilized zirconia (YSZ) substrates. By combining electrochemical impedance spectroscopy (EIS) with x-ray photoemission spectroscopy (XPS) and x-ray absorption spectroscopy XAS measurements, we conclude that electrically driven cation migration away from the two-phase gas-cathode interface results in improved electrochemical performance. Our results provide support to the premise that the removal of surface passivating phases containing Sr2+ and Mn2+, which readily form at elevated temperatures even in O2 atmospheric pressures, is responsible for the improved cathodic performance upon application of a bias.

A rocket payload using focusing X-ray optics for the observation of soft cosmic X-rays

1971 ◽  
Vol 91 (3) ◽  
pp. 451-459 ◽  
Author(s):  
P. Gorenstein ◽  
B. Harris ◽  
H. Gursky ◽  
R. Giacconi
Keyword(s):  
X Rays ◽  
Ray Optics ◽  
X Ray

Development of an Ultraprecise Piezoelectric Deformable Mirror for Adaptive X-Ray Optics

2012 ◽  
Vol 523-524 ◽  
pp. 50-53
Author(s):  
Hiroki Nakamori ◽  
Satoshi Matsuyama ◽  
Shota Imai ◽  
Takashi Kimura ◽  
Yasuhisa Sano ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
High Spatial Frequency ◽  
Deformable Mirror ◽  
Optical Parameters ◽  
X Rays ◽  
Fizeau Interferometer ◽  
Ray Optics ◽  
Wavefront Correction ◽  
X Ray ◽  
Kirchhoff Integral

Ultraprecise piezoelectric deformable mirrors have been developed to construct adaptive X-ray focusing optics whose optical parameters can be varied while simultaneously performing wavefront correction. We designed and developed a deformable mirror that did not have high-spatial-frequency deformation errors. Using a Fizeau interferometer, we demonstrated that the mirror could be deformed with a peak-to-valley figure accuracy of 5 nm. In addition, wave-optical simulations based on the Fresnel–Kirchhoff integral revealed that the mirror could focus hard X-rays to 90 nm under diffraction-limited conditions.

Bragg and Fresnel Diffraction Imaging Using Highly Coherent X-Rays

1998 ◽  
Vol 4 (S2) ◽  
pp. 376-377
Author(s):  
P. Cloetens ◽  
J. Baruchel ◽  
J.P. Guigay ◽  
W. Ludwig ◽  
L. Mancini ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Optical Path Length ◽  
Fresnel Diffraction ◽  
Crystal Defects ◽  
Bragg Diffraction ◽  
X Rays ◽  
Transmitted Beam ◽  
X Ray ◽  
Diffraction Imaging ◽  
Phase Variations

X-ray imaging started over a century ago. For several decades its only form was absorption radiography, in which contrast is due to local variations in beam attenuation. About forty years ago, a new form of X-ray imagery, Bragg-diffraction imaging or X-ray topography, developed into practical use. It directly reveals crystal defects in the bulk of large single crystals, and paved the way to microelectronics by leading to the growth of large, practically perfect, crystals. The advent of third-generation synchrotron radiation sources of X-rays such as ESRF and APS is now making possible, through the coherence of the X-ray beams, a novel form of radiography, in which contrast arises from phase variations across the transmitted beam, associated with optical path length differences, through Fresnel diffraction. Phase radiography and its three-dimensional companion, X-ray phase tomography, are providing new information on the mechanics of composites as well as on biological materials.

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