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ABSTRACT: 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.
Journal of Synchrotron Radiation 01/2012; 19(Pt 1):101-5. · 2.73 Impact Factor
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ABSTRACT: A novel two-beam X-ray interferometer using two multiple Bragg--Laue
(MBL) mode interferometers has been developed. The first MBL
interferometer was utilized not only as a monochromator to generate a
highly coherent beam but also as a beam splitter. The second MBL
interferometer was used as an analyzer. By using this two-beam X-ray
interferometer, interference fringes were observed as a function of the
thickness of a phase plate inserted in one path of incident X-rays. The
visibility of the measured fringes is approximately 25%. Some advantages
of this MBL interferometer are pointed out.
Journal of the Physical Society of Japan 07/2011; 80(8):3001. · 2.36 Impact Factor
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ABSTRACT: Interference fringes in multiple Bragg-Laue mode have been measured from the lateral surface of an Si plane-parallel crystal by changing the distance L between the incident point of X-rays and the crystal edge for two sample crystals with different thicknesses H. The period of the interference fringes becomes large when the distance L becomes large or the thickness H becomes small. When the ratio L/H is larger than 15, a shorter period of oscillation appears in addition to the interference fringes. These variations are explained by considering the beams in multiple Bragg-Laue modes based on the dynamical theory of diffraction. When L/H is less than 15, the measured fringes are well reproduced by taking account of interference between beams in the Bragg-Laue and the Bragg-Bragg-Laue modes. The short period of the oscillations observed for L/H > 15 is reproduced by adding the intensities of the beams in higher-order Bragg-Laue mode. The interference fringes calculated by taking the visibility into account show good agreement with the measured ones.
Acta crystallographica. Section A, Foundations of crystallography 03/2011; 67(Pt 2):154-9. · 49.93 Impact Factor
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ABSTRACT: Interference fringes are measured in the diffraction from the surface as well as from the lateral surface of an Si single-crystal strip which is deformed in cantilever bending as a function of the tip displacement. The interference fringes are observed only when the bending strain is applied. Both interference fringes change conspicuously by increasing the bending strain. The number of the interference fringes changes, and the positions and heights of the peaks in the fringes change. These variations can be explained by the change of the interference between the beams in multiple Bragg-Laue modes and those of mirage diffraction based on the dynamical theory of diffraction.
Acta crystallographica. Section A, Foundations of crystallography 05/2010; 66(Pt 3):421-6. · 49.93 Impact Factor
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ABSTRACT: X-ray interference fringes in the beams diffracted from a lateral surface of a thin plane-parallel crystal are measured and analyzed using Wagner's approach [Wagner (1956), Z. Phys. 146, 127-168]. It is found that the fringes are caused by the interference between the internal waves excited by the incident beam in both the Bragg-Laue case and the Bragg-Bragg-Laue case. The period of the interference fringes is shown to be proportional to the distance between the incident point of the X-ray and the crystal edge, and to be inversely proportional to the crystal thickness.
Acta crystallographica. Section A, Foundations of crystallography 08/2009; 65(Pt 4):253-8. · 49.93 Impact Factor
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ABSTRACT: By using X-rays from synchrotron radiation, we measured the rocking curves due to only the imaginary part of the atomic scattering factor in Laue case. The interference fringes are observed which are totally different from the Pendellösung fringe. The fringes of the diffracted and transmitted rocking curves are in-phase with each other. We studied the origin of the in-phase fringes by using the complex dispersion surface and the electric field in the crystal, and also the relation with a coupled pendulum.
Physica Status Solidi (A) Applications and Materials 06/2009; 206(8):1865 - 1869. · 1.46 Impact Factor
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ABSTRACT: X-Ray rocking curves from side surface of a thin plane-parallel Ge crystal are measured under the condition where the dispersion of the refracted angle is quite large. In the diffracted beams from side surface are observed, which are analysed by using Wagner's approach for Bragg–(Bragg)m–Laue case. The origin of the fringes is explained by the interference between diffraction beams in Bragg–Laue case and that in Bragg–Bragg–Laue case.
Physica Status Solidi (A) Applications and Materials 06/2009; 206(8):1855 - 1859. · 1.46 Impact Factor
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ABSTRACT: X-ray rocking curves in the Bragg-Laue case diffracting from the side surface of a plane-parallel crystal have been measured using a high-resolution optical system. The full width at half-maximum of the rocking curves is approximately three times narrower than that measured from the top surface. The characteristics of the transmitted beam from the side surface are almost the same as those through a thin crystal in the Bragg case. The rocking curves and the direction of X-ray energy flow in the crystal observed in the experiment can be reproduced using Wagner's approach [Wagner (1956), Z. Phys. 146, 127-168].
Acta Crystallographica Section A Foundations of Crystallography 10/2008; 64(Pt 5):515-8. · 2.08 Impact Factor
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ABSTRACT: Variations of peak position of the rocking curve in the Bragg case are measured from a Ge thin crystal near the K-absorption edge. The variations are caused by a phase change of the real part of the atomic scattering factor. Based on the measurement, the values of the real part are determined with an accuracy of better than 1%. The values are the most reliable ones among those reported values so far as they are directly determined from the normal atomic scattering factors.
Acta Crystallographica Section A Foundations of Crystallography 04/2008; 64(Pt 2):321-5. · 2.08 Impact Factor
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ABSTRACT: The interference fringe caused by lattice distortion around a defect is observed in the resonant scattering X-ray topography for the GaAs 200 reflection in the Laue case. The amplitude of the fringe can be maximized when the Fourier transform of the imaginary part of X-ray polarizability χhi is zero. The fringe position relative to the defect shifts when the incident angle is varied, and the fringe spacing changes as a function of the distance from the defect. A kinematical image can be distinguished from a dynamical one by observing the image position when the incident angle is varied in the case of χhi = 0. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Physica Status Solidi (A) Applications and Materials 07/2007; 204(8):2694 - 2699. · 1.46 Impact Factor
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ABSTRACT: It is shown that the locus of the f' + if'' plot in the complex plane, f' being determined from measured f'' by using the dispersion relation, looks like a semicircle very near the absorption edge of Ge. The semicircular locus is derived from a quantum theory of X-ray resonant scattering when there is a sharp isolated peak in f'' just above the K-absorption edge. Using the semicircular behavior, an approach is proposed to determine the anomalous scattering factors in a crystal by fitting known calculated values based on an isolated-atom model to a semicircular focus. The determined anomalous scattering factors f' show excellent agreement with the measured values just below the absorption edge. In addition, the phase determination of a crystal structure factor has been considered by using the semicircular behavior.
Acta Crystallographica Section A Foundations of Crystallography 12/2005; 61(Pt 6):553-6. · 2.08 Impact Factor
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ABSTRACT: Plane-wave topographs of X-rays for the GaAs 200 reflection were recorded using synchrotron radiation near the K-absorption edges of Ga and As. The topographic contrasts caused by lattice defects were changed by tuning the X-ray energy to four typical resonant scattering conditions. A sharp image of a lattice defect was observed when the Borrmann effect disappeared. When the Borrmann effect was conspicuous, an image of lattice distortion around a dislocation was observed, and its contrast was reversed by changing the phase factor of the resonant scattering. The lattice distortion image and its contrast reversal are discussed based on the resonant scattering dynamical theory by introducing the edge-dislocation model. The results show that topographs using resonant scattering should be a new characteristic method in synchrotron topography.
Journal of Synchrotron Radiation 06/2004; 11(Pt 3):266-71. · 2.73 Impact Factor
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ABSTRACT: In the Bragg case, X-ray beams suffer from anomalous absorption due to extinction effects without photo-absorption and are localized in the surface when X-ray total reflection occurs around an exact Bragg angle from a perfect crystal. On the other hand, the Borrmann effect due to anomalous transmission occurs in a thin perfect crystal with photo-absorption under a proper condition. There is a clear distinction between the extinction effect and the Borrmann effect. It is found that it is possible to separate the Borrmann effect from the extinction effect when the real part of the atomic scattering factor is zero. The calculated rocking curves agree well with the measured ones around the Ge K-absorption edge of the Ge 844 reflection.
Acta Crystallographica Section A Foundations of Crystallography 12/2002; 58(Pt 6):552-8. · 2.08 Impact Factor
