A new approach to the study of nuclear Bragg scattering using synchrotron radiation.

Nuclear Bragg scattering of synchrotron radiation from isotopically enriched sup (57) Fe sub 2 O sub 3 has been observed without need for delayed coincidence techniques. The use of a high resolution premonochromator providing a 5 meV energy spread and 0.4 arc sec collimation allows for high resolution studies of dynamical diffraction effects. In particular, the observed intensity of the pure nuclear (7,7,7) reflection implies a dramatic decrease of the effective lifetime due to coherent scattering.