scholarly journals Moiré pattern from a multiple Bragg–Laue interferometer

2011 ◽  
Vol 19 (1) ◽  
pp. 101-105 ◽  
Author(s):  
Kenji Hirano ◽  
Tomoe Fukamachi ◽  
Yoshinobu Kanematsu ◽  
Sukswat Jongsukswat ◽  
Riichirou Negishi ◽  
...  
Keyword(s):  
Incident Beam ◽  
Platinum Wire ◽  
X Rays ◽  
X Ray ◽  
Moire Pattern ◽  
Moiré Pattern ◽  
Interference Fringes ◽  
Section Topography ◽  
Mode A

In X-ray section topography of Si 220 diffraction in a multiple Bragg–Laue mode, a moiré pattern is observed when the incident beam is divided into two parts by inserting a platinum wire in the middle of the beam. The moiré pattern can be explained by the summation of two interference fringes corresponding to the two incident beams. The coherency of the X-rays from the bending-magnet beamline is estimated using the moiré pattern.

Collimating Montel mirror as part of a multi-crystal analyzer system for resonant inelastic X-ray scattering

2016 ◽  
Vol 23 (4) ◽  
pp. 880-886 ◽  
Author(s):  
Jungho Kim ◽  
Xianbo Shi ◽  
Diego Casa ◽  
Jun Qian ◽  
XianRong Huang ◽  
...  
Keyword(s):  
Energy Resolution ◽  
Incident Beam ◽  
X Rays ◽  
X Ray ◽  
X Ray Scattering ◽  
Angular Acceptance ◽  
Crystal Analyzer ◽  
Present Design ◽  
Photon Source ◽  
Ray Scattering

Advances in resonant inelastic X-ray scattering (RIXS) have come in lockstep with improvements in energy resolution. Currently, the best energy resolution at the IrL3-edge stands at ∼25 meV, which is achieved using a diced Si(844) spherical crystal analyzer. However, spherical analyzers are limited by their intrinsic reflection width. A novel analyzer system using multiple flat crystals provides a promising way to overcome this limitation. For the present design, an energy resolution at or below 10 meV was selected. Recognizing that the angular acceptance of flat crystals is severely limited, a collimating element is essential to achieve the necessary solid-angle acceptance. For this purpose, a laterally graded, parabolic, multilayer Montel mirror was designed for use at the IrL3-absorption edge. It provides an acceptance larger than 10 mrad, collimating the reflected X-ray beam to smaller than 100 µrad, in both vertical and horizontal directions. The performance of this mirror was studied at beamline 27-ID at the Advanced Photon Source. X-rays from a diamond (111) monochromator illuminated a scattering source of diameter 5 µm, generating an incident beam on the mirror with a well determined divergence of 40 mrad. A flat Si(111) crystal after the mirror served as the divergence analyzer. From X-ray measurements, ray-tracing simulations and optical metrology results, it was established that the Montel mirror satisfied the specifications of angular acceptance and collimation quality necessary for a high-resolution RIXS multi-crystal analyzer system.

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.

Probing the spatial coherence of wide X-ray beams with Fresnel mirrors at BL25SU of SPring-8

2019 ◽  
Vol 26 (3) ◽  
pp. 756-761
Author(s):  
Yoko Takeo ◽  
Hiroto Motoyama ◽  
Yasunori Senba ◽  
Hikaru Kishimoto ◽  
Haruhiko Ohashi ◽  
...  
Keyword(s):  
Optical System ◽  
Spatial Coherence ◽  
Optical Systems ◽  
X Rays ◽  
X Ray ◽  
Interference Fringes ◽  
Radiation Sources ◽  
Wide Wavelength Range ◽  
Valuable Method ◽  
The Relationship

Probing the spatial coherence of X-rays has become increasingly important when designing advanced optical systems for beamlines at synchrotron radiation sources and free-electron lasers. Double-slit experiments at various slit widths are a typical method of quantitatively measuring the spatial coherence over a wide wavelength range including the X-ray region. However, this method cannot be used for the analysis of spatial coherence when the two evaluation points are separated by a large distance of the order of millimetres owing to the extremely narrow spacing between the interference fringes. A Fresnel-mirror-based optical system can produce interference patterns by crossing two beams from two small mirrors separated in the transverse direction to the X-ray beam. The fringe spacing can be controlled via the incidence angles on the mirrors. In this study, a Fresnel-mirror-based optical system was constructed at the soft X-ray beamline (BL25SU) of SPring-8. The relationship between the coherence and size of the virtual source was quantitatively measured at 300 eV in both the vertical and horizontal directions using the beam. The results obtained indicate that this is a valuable method for the optimization of optical systems along beamlines.

Absorption and secondary scattering of X-rays with an off-axis small beam for a cylindrical sample geometry

2019 ◽  
Vol 75 (2) ◽  
pp. 362-369
Author(s):  
Daniel C. Van Hoesen ◽  
James C. Bendert ◽  
Kenneth F. Kelton
Keyword(s):  
Multiple Scattering ◽  
Incident Beam ◽  
Cylindrical Sample ◽  
X Rays ◽  
Beam Size ◽  
X Ray ◽  
Sample Geometry ◽  
Integral Forms ◽  
Secondary Scattering ◽  
X Ray Absorption

Expressions for X-ray absorption and secondary scattering are developed for cylindrical sample geometries. The incident-beam size is assumed to be smaller than the sample and in general directed off-axis onto the cylindrical sample. It is shown that an offset beam has a non-negligible effect on both the absorption and multiple scattering terms, resulting in an asymmetric correction that must be applied to the measured scattering intensities. The integral forms of the corrections are first presented. A small-beam limit is then developed for easier computation.

scholarly journals X-ray analysis of the crystal-structure of rutile and cassiterite

1917 ◽  
Vol 93 (653) ◽  
pp. 418-427 ◽  
Keyword(s):  
Crystal Structure ◽  
Royal Society ◽  
Incident Beam ◽  
X Rays ◽  
Narrow Beam ◽  
X Ray ◽  
Axis Of Rotation ◽  
Ordinary Light ◽  
The Face ◽  
Ionisation Chamber

The present paper deals with the results obtained in the investigation of the atomic structure of rutile and cassiterite by the X-ray spectrometer. A detailed account of the method has been given by Prof. Bragg and his son, W. L. Bragg, in a series of papers communicated to the Royal Society. It consists essentially in allowing a narrow beam of monochromatic X-rays—in this case the rhodium rays—to fall on the face of the crystals, mounted on a spectrometer table, the axis of rotation of which passes through the face of the crystal. The beam is “reflected” by the atom planes parallel to this face, and thence passes into an ionisation chamber, containing methyl bromide in order to increase the ionisation current. The setting of crystal and chamber with regard to the incident beam corresponds to that for which ordinary light is reflected.

Generalized grazing-incidence-angle X-ray diffraction (G-GIXD) using image plates

1998 ◽  
Vol 5 (3) ◽  
pp. 488-490 ◽  
Author(s):  
Yasuo Takagi ◽  
Masao Kimura
Keyword(s):  
Incidence Angle ◽  
Incident Beam ◽  
Grazing Incidence ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface And Interface ◽  
Out Of Plane ◽  
Grazing Incidence Angle ◽  
Interface Layers

A new and more `generalized' grazing-incidence-angle X-ray diffraction (G-GIXD) method which enables simultaneous measurements both of in- and out-of-plane diffraction images from surface and interface structures has been developed. While the method uses grazing-incidence-angle X-rays like synchrotron radiation as an incident beam in the same manner as in `traditional' GIXD, two-dimensional (area) detectors like image plates and a spherical-type goniometer are used as the data-collection system. In this way, diffraction images both in the Seemann–Bohlin (out-of-plane) and GIXD geometry (in-plane) can be measured simultaneously without scanning the detectors. The method can be applied not only to the analysis of the in-plane crystal structure of epitaxically grown thin films, but also to more general research topics like the structural analysis of polycrystalline mixed phases of thin surface and interface layers.

A study of X-ray multiple diffraction by means of section topography

2015 ◽  
Vol 71 (5) ◽  
pp. 519-525 ◽  
Author(s):  
V. G. Kohn ◽  
I. A. Smirnova
Keyword(s):  
Computer Simulations ◽  
Azimuthal Angle ◽  
Silicon Single Crystal ◽  
Multiple Diffraction ◽  
X Ray ◽  
Interference Fringes ◽  
Laboratory Source ◽  
Diffraction Region ◽  
First Time ◽  
Section Topography

The results of theoretical and experimental study are presented for the question of how the X-ray multiple diffraction in a silicon single crystal influences the interference fringes of section topography for the 400 reflection in the Laue case. Two different cases of multiple diffraction are discovered for zero and very small values of the azimuthal angle for the sample in the form of a plate with the surface normal to the 001 direction. The cases are seen on the same topogram without rotation of the crystal. Accurate computer simulations of the section topogram for the case of X-ray multiple diffraction are performed for the first time. It is shown that the structure of interference fringes on the section topogram in the region of multiple diffraction becomes more complicated. It has a very sharp dependence on the azimuthal angle. The experiment is carried out using a laboratory source under conditions of low resolution over the azimuthal angle. Nevertheless, the characteristic inclination of the interference fringes on the tails of the multiple diffraction region is easily seen. This phenomenon corresponds completely to the computer simulations.

On-line monitoring of the spatial properties of hard X-ray free-electron lasers based on a grating splitter

2019 ◽  
Vol 26 (3) ◽  
pp. 619-628 ◽  
Author(s):  
Wenqiang Hua ◽  
Guangzhao Zhou ◽  
Zhe Hu ◽  
Shumin Yang ◽  
Keliang Liao ◽  
...  
Keyword(s):  
Free Electron ◽  
Incident Beam ◽  
Single Pulse ◽  
X Rays ◽  
Free Electron Lasers ◽  
Spatial Characteristics ◽  
X Ray ◽  
First Order ◽  
Spatial Properties ◽  
On Line

X-ray free-electron lasers (XFELs) play an increasingly important role in addressing the new scientific challenges relating to their high brightness, high coherence and femtosecond time structure. As a result of pulse-by-pulse fluctuations, the pulses of an XFEL beam may demonstrate subtle differences in intensity, energy spectrum, coherence, wavefront, etc., and thus on-line monitoring and diagnosis of a single pulse are required for many XFEL experiments. Here a new method is presented, based on a grating splitter and bending-crystal analyser, for single-pulse on-line monitoring of the spatial characteristics including the intensity profile, coherence and wavefront, which was suggested and applied experimentally to the temporal diagnosis of an XFEL single pulse. This simulation testifies that the intensity distribution, coherence and wavefront of the first-order diffracted beam of a grating preserve the properties of the incident beam, by using the coherent mode decomposition of the Gaussian–Schell model and Fourier optics. Indicatively, the first-order diffraction of appropriate gratings can be used as an alternative for on-line monitoring of the spatial properties of a single pulse without any characteristic deformation of the principal diffracted beam. However, an interesting simulation result suggests that the surface roughness of gratings will degrade the spatial characteristics in the case of a partially coherent incident beam. So, there exists a suitable roughness value for non-destructive monitoring of the spatial properties of the downstream beam, which depends on the specific optical path. Here, experiments based on synchrotron radiation X-rays are carried out in order to verify this method in principle. The experimental results are consistent with the theoretical calculations.

scholarly journals On the ionization of light gases by X-rays. II.—The ionization of hydrogen by recoil electrons

1933 ◽  
Vol 141 (845) ◽  
pp. 686-696 ◽  
Keyword(s):  
Total Energy ◽  
Wave Length ◽  
Practical Importance ◽  
Incident Beam ◽  
Direct Methods ◽  
X Rays ◽  
Recoil Electron ◽  
X Ray ◽  
Experimental Errors

In Part I, p. 669, a technique has been described for determining the ratio of the ionization in a light gas (hydrogen or helium) to that in air when ionized by the same X-ray beam, homogeneous rays of medium wave-length and soft heterogeneous rays being available for the measurement. The ionization ratio can be converted into the ratio of the energies absorbed by the two gases by making use of the known value of the ratio of the energies required to form a pair of ions in the two gases; and since the ionization in air is due almost entirely to photoelectrons and the absorption coefficient is known, the energy in the incident beam can be obtained from the energy absorbed by air; thus the energy absorbed by the light gas can be correlated with the energy in the incident beam. The radiation of medium wave-length (about ½ A.) ionizes the light gas chiefly through the agency of recoil electrons, so that after applying a correction (obtained from the soft ray ratio) for the ionization due to photoelectrons, the fraction of the energy in the incident beam converted into recoil electron energy by the gas may be obtained, and compared with the predictions of the quantum theory of recoil scattering. In this paper the comparison is carried out with measurements on hydrogen, and for convenience it will be made between the experimental and calculated values of the ionization ratios. Excluding the early work of Shearer already mentioned in I no experimental determination of the total energy associated with recoil electrons has hitherto been made by any method as direct as the present one, though less direct methods have been employed. In general, however, the experimental technique was open to criticism, and the interpretation of the measurements uncertain, so that it is not surprising that the results were inconsistent either with one another or with theory. It is also possible to calculate the total energy associated with recoil electrons from other experimental facts concerning recoil scattering, but the experimental errors involved combine to make the final result very unreliable. The energy associated with recoil electrons is, however, not only of theoretical interest but also of great practical importance, since all effects arising from scattering, in the scattering substance itself, are due to recoil electron emission.

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