The Kinematic Theory of Gamma‐Quantum Coherent Scattering in the Field of Ultrasonic Waves

Abstract

Papers /1, 2/ consider the possibility of Mossbauer gamma-quantum modulation by ultrasonic (US) coherent waves. They indicate that in the case of coherent excitation of US oscillations in the absorbers the intensities of the unshifted line and of the satellites oscillate depending on the excitation amplitude. In particular, at A / X w 2.4 (where A is the US wave amplitude, X is the gamma-quantum wavelength) the unshifted line intensity becomes of the order of the experimental error. The latter may possibly be used in separating the elastic Rayleigh scattering from the nuclear resonant one.The existence of these channels of scattering and their interference were theoretically predicted and experimentally proved in /3 to 8 / .The present paper considers the behaviour of the diffraction pattern when US waves are excited in the scatterer. With this aim the gamma-quantum scattering was investigated in single crystals with cubic symmetry affected by US oscillations. In /9/ the authors performed an analysis for the differential cross-section of the gamma-quantum recoilless scattering without US excitation. The account of US oscillations in the expression for the differential scattering cross-section (d d/dw dS1 ) is realized through the substitution of &(t) for %(t) + Acos(Qt -3 R . ), where R. = g!o) + fiT, hl and a a r e the frequency and wave vector of the acoustic oscillations, respectively.