Resonant X-ray scattering from a rotating medium: The Nuclear Lighthouse Effect

A coherently excited nuclear state is carried with a rotating sample so tha t its radiative decay is redirected by the rotation angle that has develope d during its lifetime. As a result, the time spectrum of the nuclear decay is mapped to an angular scale. This effect has been observed in nuclear res onant scattering of synchrotron radiation from a rotating Fe-57 metal foil. Applications with respect to elastic and inelastic nuclear resonant scatte ring are discussed.