  The newest neutron scattering applications are highly intensity-limited
techniques that demand reducing the neutron losses between source and
detectors. In addition, the nuclear industry demands more accurate data and
procedures for the design and optimization of advanced fission reactors,
especially for the treatment of fuel and moderator materials. To meet these
demands, it is necessary to improve the existing calculation tools, through the
generation of better models that describe the interaction of neutrons with the
systems of interest. The Neutron Physics Department at Centro Atomico Bariloche
(CNEA, Argentina) has been developing over the time new models for the
interaction of slow neutrons with materials, to produce scattering kernels and
cross section data in the thermal and cold neutron energy region. Besides the
studies carried out on neutron moderators, we have recently begun looking at
materials that could serve as efficient neutron reflectors over those energy
ranges. In this work we present the results of transmission and scattering
experiments on diamond nanopowder and magnesium hydride, carried out
simultaneously at the VESUVIO spectrometer (ISIS, UK), and compare them with
newly generated cross-section libraries.
