EVALUATION OF NEUTRON CROSS-SECTIONS FOR LIQUID HYDROGEN AND DEUTERIUM FOR THE DESIGN OF COLD NEUTRON SOURCES
Institut für Kernenergetik und Energiesysteme, University of Stuttgart,
Pfaffenwaldring 31, D-7000 Stuttgart 80, West Germany
Cross-sections for slow neutron scattering from H2 and D2 have been calculated taking into account the liquid state. The ability of the model is demonstrated by comparison with experimental results for differential and total cross-sections. For applications the scattering law S(α,β) has been prepared in the ENDF-5-format for different temperatures as a basis for the generation of scattering matrices. From calculations of neutron spectra with different scattering models it turns out that the gain factor for cold neutrons is sensitive to the liquid state. Below 1 meV the frequently used Young-Koppel model for a molecular H2-gas overestimates the gain factor by about 50 %.
KEYWORDS: cold neutrons, liquid hydrogen, liquid deuterium, intermolecular interference, double differential cross-sections, total cross-sections, gain factors