A new thermal neutron scattering kernel for liquid hydrogen

We have used recent experimental data on the dynamics of liquid Hydrogen to produce a new description of the interaction of slow neutrons with this cryogenic moderator. The molecular translational motion, for both diffusive and collective degrees of freedom, has been reanalysed and represented by a different spectral frequency distribution compared to existing ones. We also included explicitely the molecular vibrations into the physical model. Recent structural studies on liquid deuterium were considered in the present work, to produce by a density-scaling procedure a realistic structure factor for the calculation of the scattering law at different temperatures within the range corresponding to the liquid phase of H-2. This model was employed as input data to, generate new scattering cross-section libraries using the NJOY code. The preliminary validation tests performed so far using the new library indicate that they are able to produce results in good agreement with the available experimental information. (C) 2003 Published by Elsevier B.V.