Diffraction of a focused x-ray beam from La_3Ga_5SiO_(14) crystal modulated by surface acoustic waves

摘要

X-ray Bragg diffraction on an acoustically modulated La_3Ga_5SiO_(14) crystal (langasite, LGS) was studied in the saggital geometry where a surface acoustic wave (SAW) serves as diffraction grating of normal incidence. A set of parabolic compound Be refracting lenses was used to focus x-ray radiation in order to obtain good angular and spatial resolution of diffraction satellites. X-ray diffraction spectra analysis provided information on the acoustic properties of the LGS crystal and enabled the determination of SAW amplitudes and wavelengths.