A new experimental scheme for nuclear γ-resonance time-domain interferometry.

Abstract

Time-domain interferometry (TDI) based on nuclear resonant scattering of synchrotron radiation by Mössbauer nuclei is a promising technique to study slow dynamics at the interatomic length scale. In order to improve the efficiency of this technique, a new TDI scheme is developed involving the use of a nuclear absorber with a two-line energy spectrum combined with a single-line spectrum. Different from other TDI setups, the issue of external vibrations is much reduced since the two absorbers are at rest and no velocity transducer is used. This allows measuring beating patterns with satisfying statistical accuracy and contrast up to 350 ns. We report here the characterization of the experimental setup necessary for the implementation of this new scheme. The model required for the description of the beating pattern produced by a three-line spectrum system is also discussed in detail. Finally, we report some results for the dynamics of the prototypical glass-former ortho-terphenyl to demonstrate the possibilities offered by this new scheme.