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  • 1
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Outlined are design features of a versatile high-resolution two-axis diffractometer that is being constructed for operation at the Photon Factory as an Australian national facility. The instrument features optional use of multiple-imaging plates on a translating cassette to allow rapid recording of an almost complete range of data covering both the high-angle and small-angle scattering regime or alternatively the use of electronic detectors. The instrument will be capable of operation in various modes including the following: (i) high-resolution powder diffraction with single-channel counter and crystal analyzer, (ii) high-resolution, high-speed powder diffraction in the Debye–Scherrer mode with imaging plates as recording medium, either stationary or translating (for time-dependent studies), (iii) small-angle x-ray scattering with imaging plates as recording medium, (iv) protein crystallography in screenless Weissenberg mode, and (v) two- or three-axis single-crystal diffractometry. The salient features of the instrument are the use of a double-crystal sagittal focusing monochromator as primary monochromator together with the optional use of a condensing–collimating channel-cut (CCCC) monochromator or other channel-cut monochromator as secondary monochromator. The use of a CCCC monochromator enables fine tuning of beam position on sample, harmonic suppression, beam-condensation, and variation of wavelength bandpass. Further features include the use of high-precision incremental encoders on both axes, together with the capability of operating the whole diffractometer, including secondary monochromator and detectors, in vacuum of order 10−3 Torr in order to reduce absorption and parasitic scattering, and the use of a large camera radius (approximately 0.57 m) for the imaging plate cassette in order to increase angular resolution and signal to noise.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The x-ray-diffraction results reported here are from the first high-resolution triple-crystal experiments to be performed at the Australian National Beamline Facility at the Photon Factory. The heart of the facility is a multipurpose two-axis high-resolution vacuum diffractometer (BIGDIFF) Z. Barnea et al., Rev. Sci. Instrum. 63, 1069 (1992) capable of use for high-resolution powder diffraction (using both conventional scintillation detectors and imaging plates), protein crystallography, reflectometry, as well as single-crystal diffractometry. The present experiments were conducted on BIGDIFF in triple-crystal diffraction mode with a monolithic channel-cut Si monochromator (supplied by Professor M. Hart), a single-crystal Si sample, and a four-reflection monolithic channel-cut Si analyzer crystal. The Si(111) sample is a part of a wafer which had been implanted with 100 keV B+ ions (doses 1×1015 and 5×1015 cm−2) through a one-dimensional 0.5 μm thick oxide strip pattern with a 5.83 μm period and 4 μm open region. The triple-crystal data were collected in the form of two-dimensional intensity maps in the vicinity of the 111 Bragg peak, varying the sample rotation (ω) and the analyzer/scintillation detector rotation (2θ). The first results were collected in air both with the as-described sample and after the oxide layer had been removed. Certain slice scans (one-dimensional sections of the two-dimensional intensity maps) were also collected with a vacuum of 1 Torr and reveal considerable improvement in signal to background.The data will be compared with a recent similar study A. Yu. Nikulin et al., J. Appl. Cryst. 27, 338 (1994) performed on BL-14B at the Photon Factory. The new data collected in air indicate that lattice distortion may be mapped with a resolution of approximately 160 A(ring), to a depth of approximately 1.0 μm, providing valuable quantitative information on ion diffusion in such implanted materials. The slice scans collected in vacuum indicate that a depth resolution of 50 A(ring) is certainly achievable using BIGDIFF. The data show the excellent potential of BIGDIFF for extremely good signal to noise and very high resolution in such experiments, and the advantages of working entirely in vacuum. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Design features of a proposed high-resolution, high-speed powder diffractometer for operation at a synchrotron source are described. A key feature of the design is the use of imaging plates to record an almost complete range of data including both the high-angle and the small-angle scattering regime. The x-ray optics involve the use of a condensing-collimating channel-cut monochromator (CCCC) to achieve narrow parallel beams with cross sections of the order of 50 μm in the plane of diffraction, so that geometrical aberrations are very low and the beam cross section is well matched to the spatial resolution of the imaging plate detector. Angular resolution in 2θ of the diffractometer is easily variable, and designed to range from 0.01° upwards. Optional translation of the detector perpendicular to the incident-beam direction makes it possible to obtain time-resolved data. Applications of the instrument include high-resolution powder data collection for Rietveld analysis, studies of dynamic phenomena such as chemical reactions and phase transformations, particle-size determination, texture analysis, residual-stress measurements, single-crystal studies of the truncation-rod effect and surface scattering, microdiffraction, combined high-angle and small-angle scattering measurements, and studies of multilayer structures. As an illustration of the sort of results attainable with the proposed system, we present an oscillation photograph of the crystal-truncation rod effect for a Si wafer which was recorded at a synchrotron source using an imaging plate as the detector.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 19 (1986), S. 143-143 
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: The synchrotron X-ray results reported here are from the first high-resolution triple-crystal diffraction experiments performed at the Australian National Beamline Facility (ANBF). At the centre of the ANBF is a multipurpose high-resolution two-axis vacuum X-ray diffractometer. The Si(111) sample studied has been implanted with B+ ions through a one-dimensional SiO2 strip pattern with a 5.83 μm period and 4 μm open region, to produce a sample with a periodic superstructure in the lateral direction. The triple-crystal data were collected in the form of two-dimensional intensity maps in the vicinity of the 111 Bragg peak. Results collected in both air and vacuum are compared, as are results with and without the oxide layer. The data collected in vacuum indicate that it is possible at the ANBF to measure lattice distortions perpendicular to the sample surface with a 50 Å depth resolution.
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  • 6
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 40 (1984), S. 521-530 
    ISSN: 1600-5740
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 40 (1984), S. 530-537 
    ISSN: 1600-5740
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 16 (1983), S. 154-156 
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: A computer program for calculating the one-phonon thermal diffuse scattering (TDS) contribution to observed integrated intensities of Bragg reflections from single crystals has been written. The program is based on a general formula [Harada & Sakata (1974). Acta Cryst. A30, 77–82; Sakata & Harada (1976). Acta Cryst. A35, 426–433] which is applicable to any crystal system if elastic constants are available. The volume integral with respect to the wavevector, over the region swept out around the reciprocal-lattice point by the counter in the course of a measurement, has been simplified by use of the spherical volume approximation (SVA). Use of the SVA greatly reduces computing time for the case of large data sets. Comparison of the results with those obtained without using the SVA is given and the limitations of the SVA are pointed out.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 28 (1995), S. 803-811 
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: The triple-crystal synchrotron X-ray diffractometry data described by Nikulin, Stevenson, Hashizume, Wilkins, Cookson, Foran & Garrett [J. Appl. Cryst. (1995), 28, 57–60] has been analyzed to map out two-dimensional (two-dimensional) lattice distortions in silicon (111) crystals implanted with B+ ions of 100 keV energy through a periodic SiO2 strip pattern. The lateral periodic structure produced a series of satellite reflections associated with the 111 Bragg peak. The 2D reconstruction incorporates the use of the Petrashen–Chukhovskii method, which retrieves the phases of the Bragg waves for these satellite reflections, together with that for the fundamental. The finite Fourier series is then synthesized with the relative phases determined. Localized distortions perpendicular to the surface arising from deposited B+ ions in near-surface layers of the crystal are clearly displayed with spatial resolutions of 0.016 and 0.265 μm in the depth and lateral directions, respectively. For a sample with the oxide layer removed from the surface, two equally plausible strain maps have been obtained by assigning relative phases to 11 satellites using a sequential trial method and a minimum-energy method. Failed map reconstructions for the oxide-covered sample are discussed in terms of the non-unique solutions of the Petrashen–Chukhovskii phase-recovery algorithm and the ambiguous phases determined for the satellites.
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  • 10
    Electronic Resource
    Electronic Resource
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 39 (1983), S. 202-207 
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: The importance of carrying out TDS corrections is emphasized. Their relative effect on the derived temperature parameter values is discussed and shown to rely primarily on the experimental conditions and not on the softness of the crystal.
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