NRS

[DMauricio34]

Nuclear Resonant Scattering is a spectroscopic technique which exploits synchrotron radiation and the resonant absorption and re-emission of X-rays by atomic nuclei. It is an extension of Mössbauer spectroscopy to the time domain and uses the extremely narrow nuclear transitions of certain isotopes to study their hyperfine interactions, dynamics, and environments in materials with a high energy resolution and temporal precision.
In an NRS experiment, a very monochromatic and pulsed synchrotron radiation beam excites a sample containing Mössbauer-compatible nuclei. The nuclei absorb photons when the beam energy matches their nuclear transition energy. Since the excited nuclear state has a finite lifetime (on the order of nanoseconds), the re-emission is delayed compared to electronic scattering. This delayed response is then registered in time using a fast detector, which allows for background-free measurement of nuclear effects.
The technique is a particularly good option for investigating thin films and multilayers, where the grazing incidence geometry allows for surface sensitivity. Also, the time spectra contain oscillatory patterns (quantum beats) that reflect the hyperfine structure of the excited state and can be analyzed to obtain information on magnetic and electric interactions at the nuclear site.

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