NRS

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Nuclear resonant scattering (NRS) is a type of scattering experiment related to Möbauer spectroscopy (effectively fourier-related). It can only be done at synchrotron facilities such as Grenoble, needing the extreme brilliance and specific radiation frequencies avaible at these facilities.
It can be seen as hyperfine spectroscopy in the “time domain”, i.e. an intensity pattern in function of time in stead of like Mösbauer an energy spectrum. It is done by exciting the nuclear hyperfine levels of an atom-electron system by a short (~ps to ns) pulse of radiation, of a frequency appropriate to the system. Also, the bandwidth is so that every hyperfine level is excited simultaneously (can be arranged at a synchrotron facility). This is the first stage. The second stage is the de-excitation of these energy levels back to the ground state, releasing radiation at slightly different frequencies. The emitted energy quanta/ photons from the very close energy levels will interfere, creating a ‘beat’ pattern (visualised as a longitudinal wave). In the temporal evolution of the intensity coming from the sample, a quantized pattern can be seen, with distinct peaks and valleys, created by this beating pattern. This is called a time spectrum. The analyzation of the spectrum allows to measure:
hyperfine magnetic field
quadrupole splitting
isomeric shift
Especially, the hyperfine field really uses the radiation time dependance
Also the magnization orientation can be described, since the quantized spectrum differs depending on the orientation relative to the incoming beam polarization.

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