The nuclear lighthouse effect: a new tool for high-resolution X-ray spectroscopy

Synchrotron radiation that is coherently scattered from a rotating ensemble of resonant nuclei acquires an angular deflection proportional to the nuclear decay time. At sufficiently high rotational frequencies, the delayed radiation is well separated from the direct beam so that its time spectrum can be recorded with a position sensitive detector. This has been demonstrated employing nuclear resonant scattering of synchrotron radiation at the 23.8-keV resonance of 119Sn. Further spectroscopic applications employing high-energy nuclear resonances around 80 keV are discussed.