Neutron diffraction on piezoelectric vibrating bars

Galociová, D.; Tichý, Jan; Zelenka, J.; Michalec, R.; Chalupa, B.

doi:10.1002/pssa.19700020204

Cited by 8 publications

(1 citation statement)

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“…The Doppler effect may also play an important role in the process of diffraction in vibrating crystals (e.g. Galociova et al, 1970;Buras, Giebuttowicz, Minor & Rajca, 1972;Mikula, Michalec, Chalupa, Sedl&kov& & Petr~ilka, 1975). As was noticed by Brockhouse (1961), the rotation of a crystal at considerable speed may cause a decrease in extinction.…”

Section: Introductionmentioning

confidence: 99%

Secondary extinction in rotating single-crystal slabs

Giebułtowicz¹,

Minor²,

Sosnowska³

1979

Acta Cryst Sect A

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Variation of the diffraction conditions for neutrons in a rotating crystal frame is discussed. It is shown that the angle of deviation from the Bragg position varies with a rate equal to double the angular velocity of the crystal. This makes it possible to calculate the diffraction power for type-I Zachariasen mosaic crystals and then to obtain a solution of the Darwin equation for a rotating crystal slab with zero absorption. Further considerations refer to the space distribution of diffracted beam intensity. It is shown that, if a suitable experimental configuration is adopted, the structure factor modules can be determined from the intensity dependence on the angular velocity, and the result is independent of the mosaic-spread distribution in the sample. Results of experiments are presented.

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Section: Introductionmentioning

confidence: 99%

Secondary extinction in rotating single-crystal slabs

Giebułtowicz¹,

Minor²,

Sosnowska³

1979

Acta Cryst Sect A

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Explanation of neutron diffraction phenomena observed in vibrating piezoelectric crystals

Buras

Giebułtowicz

Minor

et al. 1972

Phys. Stat. Sol. (a)

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The neutron diffraction phenomena observed in vibrating piezoelectric crystals are explained with the assumption that a perfect single crystal – when vibrating – becomes a mosaic single crystal. The mosaic “blocks” have the form of parallel layers perpendicular to the direction of propagation of longitudinal vibrations. They are not distinctly separated from each other (as in an ordinary mosaic crystal) and change in both time and space. Two methods of calculation were used: the analytical one and the Monte Carlo method. The modulation in time of the intensity of the diffracted neutron beam as well as the increase of the mean intensity observed by other authors were explained in a semiquantitative way.

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