EFFECT OF ABSORPTION ON DYNAMICAL BRAGG-DIFFRACTION OF X-RAYS ON A CRYSTAL MODULATED BY STRONG ULTRASOUND

A theory of x-ray diffraction in crystals with electron density modula ted due to acoustic wave propagation is developed for Bragg geometry o f scattering. Expressions, describing modifications of diffraction spe ctrum as well as an integrated diffraction intensity are derived and a nalysed in certain extreme cases. Special attention is paid to the beh aviour of diffraction intensity under a strong acoustic field applied to a crystal. The crucial role of x-ray absorption in acoustically ind uced diffraction effects is established. It was shown that acoustic mo dulation results in significant increase of diffraction intensity up t o a limiting value, which is inversely proportional to the x-ray absor ption coefficient.