Dynamical neutron diffraction on perfect crystals

Abov, Yu. G.; Elyutin, N. O.; Tyulyusov, A. N.

doi:10.1134/1.1522085

Cited by 16 publications

(13 citation statements)

References 33 publications

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“…This QI approach is a quantum version of a Galton's board, which is one form of a discrete time quantum walk [18][19][20]. The model is also related to the original proposal of DD by Darwin [6,21] that involves breaking down the scattering media into layers in conformation to the invariance principle [10,22].…”

Section: Quantum Information Model For Dynamical Diffractionmentioning

confidence: 99%

Quantum-information approach to dynamical diffraction theory

et al. 2016

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We present a simplified model for dynamical diffraction of particles through a periodic thick perfect crystal based on repeated application of a coherent beam splitting unitary at coarse-grained lattice sites. By demanding translational invariance and a computationally tractable number of sites in the coarse-graining we show how this approach reproduces many results typical of dynamical diffraction theory and experiments. This approach has the benefit of being applicable in the thick, thin, and intermediate crystal regimes. The method is applied to a three-blade neutron interferometer to predict the output beam profiles, interference patterns, and contrast variation.

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Section: Quantum Information Model For Dynamical Diffractionmentioning

confidence: 99%

Quantum-information approach to dynamical diffraction theory

et al. 2016

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“…One of them used an analysing slit B (Fig. 1), similar to the classic experiments but with a width of 0.5 mm -different to the 0.1 mm slits used by Shull (1973) and Abov et al (2002) for intensity oscillation observations -to avoid 'non-sound' intensity oscillations (Shull fringes). In the other method an analysing slit was not used.…”

Section: Experimental Layoutmentioning

confidence: 99%

“…One of the most important effects of dynamical diffraction is the strongly limited intensity diffracted by an ideal crystal in the Bragg position. In the case of Laue diffraction, the distribution of the diffracted intensities has an oscillating form within a Borrmann fan (Rauch & Petrashek, 1979;Abov et al, 2002). However, the interference effects disappear very quickly if the translation symmetry in a perfect crystal is violated due to any disturbance, such as static deformation strain or lowfrequency sound excitations (Entin, 1979).…”

Section: Introductionmentioning

confidence: 97%

“…However, our experiments were carried out with monochromatic neutrons and a perfect crystal disturbed by ultrasound, instead of Shull's 'imperfect' neutrons (a white beam with high collimation) and perfect crystals. Another distinction from Shull's classical experiments is the use of position-sensitive detectors (PSDs) instead of very narrow analysing slits [0.13 mm (Shull, 1973) or 0.1 mm (Abov et al, 2002)]. …”

Section: Introductionmentioning

confidence: 99%

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Propagation of neutron spherical waves through a thick, vibrating Ge single crystal

et al. 2013

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The results of experimental and theoretical studies into the influence of ultrasound on the propagation of neutron waves in a thick Ge crystal are presented. The neutron intensity profiles were measured for the case of Laue diffraction inside the Borrmann fan. At low amplitudes of ultrasonic waves interference effects (diffraction intensity beatings) were observed. The observations were possible because of the uniform acoustic-field distribution through the whole bulk of the crystal. As distinct from the classical Shull experiments, wide analysing slits or position-sensitive detectors were used. To explain the results obtained, a modified theory for the spatial distribution of neutron diffraction intensities in the presence of acoustic excitation of the crystal is proposed. A good agreement between experiment and theory is obtained. At high amplitudes of ultrasonic waves the transition to kinematic scattering was not observed, despite the large strains in the crystalline lattice created by ultrasound. This could be connected with the formation of a superlattice having a standing wave period. A strong rise in the diffraction intensity and a sharp constriction of the neutron beam at the centre of the Borrmann fan were observed. This new effect could be used for the creation of ultrasound-controlled monochromators.

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“…Expression (7) is valid for the diffraction of a plane monochromatic wave in the symmetrical Laue case. A more rigorous expression for the shape of the reflected beam distribution can be obtained with the help of spherical neutron waves [40,41]:…”

Section: Spatial Intensity Distribution Of Diffracted Neutron Beammentioning

confidence: 99%