Neutron diffraction from sound-excited crystals

A. Remhof, K. D. Liß, A. Magerl*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

A longitudinal sound wave modulates the regular arrangement of the atomic planes of a crystal in two ways: first, the spacing between the atomic planes is modified in the regions of compression and expansion introducing a macroscopic strain and, second, the lattice planes acquire a velocity in the oscillating strain field. Bragg reflection in a strained crystal maintains the energy of the radiation, whereas Bragg reflection by a moving lattice provokes a Doppler shift of the radiation. In a diffraction experiment both these effects lead to an enlarged bandwidth of the reflection curve. The relative importance of strain and Doppler depends mainly on the radiation used. For thermal neutron scattering the profile of the rocking curve of a Bragg reflection may permit to separate the two effects. Atomic amplitudes of the sound field of 136 Å peak to peak in the bulk of the crystal can be deduced from the rocking profile. The enlarged bandwidth of a sound-excited crystal opens a possibility for diffraction-based optical elements where the trade-off between resolution and intensity can be readily modified.

Original languageEnglish
Pages (from-to)485-491
Number of pages7
JournalNuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Volume391
Issue number3
DOIs
StatePublished - 11 Jun 1997
Externally publishedYes

Keywords

  • Diffraction
  • Neutron optics
  • Solid state dynamics
  • Ultrasound

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