Synchrotron radiation effectively allows one to perform the Fourier transform of Mössbauer spectroscopy from the energy domain into the time domain: The radiation is energetically broad (in contrast to the monoenergetic γ-radiation emitted by a radioactive source), and it comes in pulses with a duration of 50 – 100 ps (in contrast to the continuously emitting radioactive source). Thus, these pulses excite all hyperfine-split resonances in the sample at the same time. In the subsequent coherent decay the interference of the emitted waves leads to a temporal beat pattern, very similar to the temporal acoustic beats of slightly-detuned tuning forks. From such a beat pattern the hyperfine interaction parameters of the nuclei in the sample can be deduced. Within the natural linewidth of the Mössbauer transition, the brilliance of synchrotron radiation sources exceeds that of radioactive sources by several orders of magnitude.
Due to the narrow nuclear resonance width in the range of neV – μeV, the scattering process takes place on time scales ranging from !s to ns. This allows for a discrimination of the resonantly scattered radiation from the non-resonant charge scattering and fluorescence that proceeds on time scales below 10−15 s.