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Title: Diffraction efficiency and diffraction bandwidth of thermal-gradient and composition-gradient crystals

Abstract

Measurements were made at the Advanced Photon Source at Argonne National Laboratory on the diffraction efficiency and diffraction bandwidth of a thermal-gradient crystal (Si) and a composition-gradient crystal (Si-Ge) to which a thermal gradient was applied. Gradient crystals are crystals in which the spacing between crystalline planes varies with the position in the crystal. This change in the crystal plane spacing is obtained by applying a thermal gradient to a single crystal or by growing a two-component crystal in which the ratio of the two components changes with position in the crystal. Measurements were made at two energies, 92.6 and 153 keV. Both crystals were 1-cm cubes. Laue diffraction (transmission diffraction) was used in all experiments. The thermal gradient was applied perpendicular to the [111] diffraction planes of the pure silicon crystal and perpendicular the [400] diffraction planes in the composition-gradient crystal (Si-Ge). The thermal gradient applied to the crystals was quite uniform. This resulted in nearly spherical surfaces for the crystalline planes. Changing the value of the thermal gradient applied to the crystals changed the radius of curvature of the spherical surface. The thermal gradients were varied between 0.0 and 114 deg. C/cm, resulting in radii of curvature frommore » near infinity down to 40 m. By adjusting the thermal gradient applied to the crystals, one obtained diffraction efficiencies between 0.90 and 0.95 and bandwidths of up to 100 arc sec. The diffraction efficiency in the Laue geometry is defined as the ratio of the intensity of the diffracted beam to the intensity of the undiffracted beam that passes through the crystal when there is no diffraction. The length of the crystal traversed by the x-ray beam was 1.0 cm in all cases.« less

Authors:
; ; ; ; ;  [1];  [2]
  1. Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)
  2. (Germany)
Publication Date:
OSTI Identifier:
20778482
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 76; Journal Issue: 12; Other Information: DOI: 10.1063/1.2130928; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ADVANCED PHOTON SOURCE; ANL; BEAMS; EFFICIENCY; GERMANIUM ALLOYS; KEV RANGE 10-100; KEV RANGE 100-1000; MONOCRYSTALS; SILICON; SILICON ALLOYS; SPHERICAL CONFIGURATION; TEMPERATURE GRADIENTS; X RADIATION; X-RAY DIFFRACTION

Citation Formats

Smither, R., Saleem, K. Abu, Beno, M., Kurtz, C., Khounsary, A., Abrosimov, N., and Institute for Crystal Growth, Max-Born-Strasse 2, D-12489 Berlin. Diffraction efficiency and diffraction bandwidth of thermal-gradient and composition-gradient crystals. United States: N. p., 2005. Web. doi:10.1063/1.2130928.
Smither, R., Saleem, K. Abu, Beno, M., Kurtz, C., Khounsary, A., Abrosimov, N., & Institute for Crystal Growth, Max-Born-Strasse 2, D-12489 Berlin. Diffraction efficiency and diffraction bandwidth of thermal-gradient and composition-gradient crystals. United States. doi:10.1063/1.2130928.
Smither, R., Saleem, K. Abu, Beno, M., Kurtz, C., Khounsary, A., Abrosimov, N., and Institute for Crystal Growth, Max-Born-Strasse 2, D-12489 Berlin. Thu . "Diffraction efficiency and diffraction bandwidth of thermal-gradient and composition-gradient crystals". United States. doi:10.1063/1.2130928.
@article{osti_20778482,
title = {Diffraction efficiency and diffraction bandwidth of thermal-gradient and composition-gradient crystals},
author = {Smither, R. and Saleem, K. Abu and Beno, M. and Kurtz, C. and Khounsary, A. and Abrosimov, N. and Institute for Crystal Growth, Max-Born-Strasse 2, D-12489 Berlin},
abstractNote = {Measurements were made at the Advanced Photon Source at Argonne National Laboratory on the diffraction efficiency and diffraction bandwidth of a thermal-gradient crystal (Si) and a composition-gradient crystal (Si-Ge) to which a thermal gradient was applied. Gradient crystals are crystals in which the spacing between crystalline planes varies with the position in the crystal. This change in the crystal plane spacing is obtained by applying a thermal gradient to a single crystal or by growing a two-component crystal in which the ratio of the two components changes with position in the crystal. Measurements were made at two energies, 92.6 and 153 keV. Both crystals were 1-cm cubes. Laue diffraction (transmission diffraction) was used in all experiments. The thermal gradient was applied perpendicular to the [111] diffraction planes of the pure silicon crystal and perpendicular the [400] diffraction planes in the composition-gradient crystal (Si-Ge). The thermal gradient applied to the crystals was quite uniform. This resulted in nearly spherical surfaces for the crystalline planes. Changing the value of the thermal gradient applied to the crystals changed the radius of curvature of the spherical surface. The thermal gradients were varied between 0.0 and 114 deg. C/cm, resulting in radii of curvature from near infinity down to 40 m. By adjusting the thermal gradient applied to the crystals, one obtained diffraction efficiencies between 0.90 and 0.95 and bandwidths of up to 100 arc sec. The diffraction efficiency in the Laue geometry is defined as the ratio of the intensity of the diffracted beam to the intensity of the undiffracted beam that passes through the crystal when there is no diffraction. The length of the crystal traversed by the x-ray beam was 1.0 cm in all cases.},
doi = {10.1063/1.2130928},
journal = {Review of Scientific Instruments},
number = 12,
volume = 76,
place = {United States},
year = {Thu Dec 15 00:00:00 EST 2005},
month = {Thu Dec 15 00:00:00 EST 2005}
}
  • No abstract prepared.
  • We report on design and performance of a high-resolution x-ray monochromator with a spectral bandwidth of {Delta}E{sub x} {approx_equal} 1.5 meV, which operates at x-ray energies in the vicinity of the backscattering (Bragg) energy E{sub H} = 13.903 keV of the (008) reflection in diamond. The monochromator is utilized for high-energy-resolution diffraction characterization of diamond crystals as elements of advanced x-ray crystal optics for synchrotrons and x-ray free-electron lasers. The monochromator and the related controls are made portable such that they can be installed and operated at any appropriate synchrotron beamline equipped with a pre-monochromator.
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  • An apparatus consisting of an optical microscope with a hot stage attachment capable of simultaneously nonuniformly heating and mechanically loading small single crystals of salt was used for this study to measure the velocities of all-liquid inclusions NaC1 and KC1 specimens under various conditions of temperature, temperature gradient, and uniaxial stress. The rate-controlling elementary step in the migration of the inclusions was found to be associated with interfacial processes, probably dissolution of the hot face. Dislocations are required for this step to take place. Furthermore, the small number of dislocation intersections with small inclusions in nearly perfect crystals causes substantialmore » variations in the velocity, a sensitivity of the velocity to mechanical loading of the crystal, and a velocity which varies approximately as the second power of the temperature gradient.« less