Cross-section model for cold neutron scattering in solid and liquid methane. II: group-constant generation

A set of energy-averaged cross-sections (group constants) for neutron scattering in solid and liquid CH4 is generated: 80 groups between 0.1 μeV and 10 eV at 20.4, 50, 90.7 and 111.7 K. Use is made of the double-differential scattering cross-section model developed by the authors, which includes molecular translations and rotations as well as intramolecular vibrations. In view of the computed results on scattering and slowing-down properties, it is expected that the group constants may serve as a powerful tool for design of an advanced cold neutron source.