Quantum Beats from Nuclei Excited by Synchrotron Radiation

Abstract

We report the experimental observation of quantum beats in the coherently scattered radiation from nuclei excited by synchrotron-radiation pulses. The measurements were made with $^{57}\mathrm{Fe}$-enriched yttrium-iron-garnet crystals, by reflection from two parallel crystals using the pure nuclear (002) Bragg reflection. The resulting beat pattern gives a sensitive direct measure both of the hyperfine splittings of individual iron nuclei, and of the energy shifts between different nuclear sites.