Ultrasound effect on neutron Bragg diffraction in a perfect and deformed silicon single crystal

Raitman, E.; Gavrilov, V. N.; Mjasischev, D.; Brezgunov, M.

doi:10.1134/s1027451009060093

Cited by 4 publications

(3 citation statements)

References 6 publications

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“…1). The resonance frequency res is equal to 19.6 MHz for Ge(111) and, taking into account the DebyeWaller factor, its value does not depend on the observed reflection (Iolin et al, 1996;Raitman et al, 2009). For the case v s > v res a linear increase in the diffraction intensity should be observed depending on the AW amplitude w (Iolin et al, 1986).…”

Section: Figurementioning

confidence: 97%

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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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Section: Figurementioning

confidence: 97%

“…The neutron-acoustic resonance frequency res is determined by equation (2) (Iolin & Entin, 1983;Raitman et al, 2009):…”

Section: Figurementioning

confidence: 99%

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

et al. 2013

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“…This result-up to a numerical factor-coincides with that obtained using expressions (8)(9)(10)(11), taking into account the inelastic scattering of neutrons. However, when US is switched on, the neutron scattering inside a crystal has more complicated behavior and cannot be satisfactorily explained only by the appearance of a new "sonic" extinction length [21]. Pendellösung fringes appear, clearly manifested at measuring the relative changes in the diffraction intensity at each point of profile η = f(2Θ B ).…”

Section: Conclusion and Summarymentioning

confidence: 99%

Neutron Back- and Front-Face Bragg Diffraction on a Thin Si Single Crystal Excited by Ultrasound

Raitman¹,

Gavrilov²,

Mjasischev³

et al. 2015

JMP

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In this research project, we measured and analyzed the spatial distribution of neutron beam Bragg diffracted from the front-and back-faces of thin Si single crystal undergoing on ultrasound excitation. For the perfect crystal, it is shown that when the acoustic wave amplitude is increased, the front-face peak position remains unchanged and its value grows linearly. The values of ultrasound wave amplitude were determined. The back-face peak becomes asymmetric and tends to disappear. New types of Pendellösung fringes in the center of the diffraction profiles were observed at the first time. It is supposed that in the perfect crystal this effect may be due to the appearance of the new "sonic" extinction length, depending on the amplitude of the ultrasonic wave. Thus, it leads to the new interference interactions between neutron wave and ultrasonic phonons. It is established that within the framework of the dynamical theory of the neutron scattering, some asymptotic models valid for the case of Laue geometry as well as Kato's quasi-classical approximation can be applied in the case of Bragg geometry also. Good agreement between experimental data and the theory has been obtained.

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Ultrasound and hypersound generation of new-type solitons and bisolitons in crystals

Dubovsky

Орлов

2012

Jetp Lett.

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Ultrasound effect on neutron Bragg diffraction in a perfect and deformed silicon single crystal

Cited by 4 publications

References 6 publications

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

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

Neutron Back- and Front-Face Bragg Diffraction on a Thin Si Single Crystal Excited by Ultrasound

Ultrasound and hypersound generation of new-type solitons and bisolitons in crystals

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