We propose to employ the NCS in the mass-selective mode to search for microscopic origins of high H- ionic conductivity in barium hydride and deuteride. This will allow us to assess the role of the nuclear quantum effects in the conductance mechanism proposed in the literature, as well as the possible magnitude and anisotropy of the H/D isotope effect. We propose to tap onto the full potential of the Vesuvio beamline by concurrently measuring Compton recoil peaks of H/D and Be, neutron transmission and diffraction, as well as, neutron-gamma resonances across the Orthorhombic (P n m a) → hexagonal (P 63 / m m c) phase transition at 500C: