Coherent scattering of a synchrotron radiation pulse by nuclei in vibrating crystals

A theory describing the time evolution of coherent scattering of a synchrotron radiation pulse by a nuclear ensemble in a crystal subjected to acoustic vibrations is presented for the case where the nuclei are vibrated in unison. A general multiple-diffraction scattering is considered which involves scattering in the forward direction as well as the two-beam Bragg or Laue diffraction as particular cases. The vibrations cause only the phase shift of the resonantly scattered radiation field which depends on the positions of nuclei at the moments of excitation and de-excitation. The time evolution as a result turns out to be insensitive to vibrations. It is shown that the time evolution of scattering from two vibrating crystals contains information on their relative motion

Nuclear resonant scattering of synchrotron radiation from

Nuclear resonant scattering of synchrotron radiation from the 25.6 keV level of 161Dy is studied with two techniques: nuclear forward scattering (NFS) and nuclear incoherent scattering (NIS). NFS time spectra of Dy metal are measured at temperatures ranging from 15 K to 80 K. They reveal electron spin relaxation in ferromagnetic dysprosium with long relaxation times of $\simeq 10{--}30$ ns. NIS energy spectra of Dy2O3 at room temperature are measured with meV resolution. Scattering accompanied by phonon excitation is observed