Neutron direct-geometry time-of-flight chopper spectroscopy is instrumental in studying fundamental excitations of vibrational and/or magnetic origin. We report here that techniques in super-resolution optical imagery (which is in real-space) can be adapted to enhance resolution and reduce noise for a neutron spectroscopy (an instrument for mapping excitations in reciprocal space). The procedure to reconstruct super-resolution energy spectra of phonon density of states relies on a realization of multiframe registration, accurate determination of the energy-dependent point spread function, asymmetric nature of instrument resolution broadening, and iterative reconstructions. Applying these methods to phonon density of states data for a graphite sample demonstrates contrast enhancement, noise reduction, and ∼5-fold improvement over nominal energy resolution. The data were collected at three different incident energies measured at the wide angular-range chopper spectrometer at the Spallation Neutron Source.
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In DGS spectra, single peak widths have an important meaning as a measure of lifetimes of excitations.
Sample defects may also cause differences.
A series of Gaussian resolution functions with different widths were convolved with the DFT DOS curve and compared to the reconstructed DOS. The width of the Gaussian function with the best match is regarded the effective resolution.