TIME SPECTRA OF A NEARLY-SINGLE-LINE PURE NUCLEAR REFLECTION EXCITED BY SYNCHROTRON RADIATION

The time dependence of the coherent response of a FeBO357 single crystal excited by synchrotron-radiation (SR) pulses was studied in the pure nuclear (333) Bragg reflection near the Néel temperature, where the Mössbauer reflection spectrum consists of nearly a single line of almost natural linewidth. The time spectra revealed a delayed reemission of quanta into the Bragg direction starting at zero intensity. This behavior was determined by two factors: the coherent decay of the nuclear excited state and the interference of two nearly coinciding hyperfine components. © 1990 The American Physical Society.