Enhancement of counting statistics and noise reduction in the forward-scattering detectors on the VESUVIO spectrometer

New evidence of the increased count rate in deep inelastic neutron scattering spectra is provided. Experiments were performed using photon-sensitive yttrium-aluminum-perovskite detectors, installed on the VESUVIO spectrometer at the ISIS pulsed neutron and muon source. At present, these detectors work with a low-level discrimination threshold measuring photons with energy greater than 600 keV in order to avoid background photons from the boron in the beam stop, and other environmental sources. We discuss the advantage in reducing the level of the threshold so as to detect some high-intensity low-energy prompt-gamma rays emitted after the radiative capture of 4.9 eV neutrons by gold, used as energy analyser on the VESUVIO spectrometer. This work shows an improvement of the statistical poissonian error bars and noise on the difference of spectra recorded with and without the energy analyser. The application of such new acquisition strategy discussed here will improve the detection limit of hydrogen atoms in samples, as well as allow a more precise line-shape analysis of nuclear momentum distributions, mentioning just few applications of deep inelastic neutron scattering experiments on VESUVIO.