Neutronic study of spherical cold-neutron sources composed of liquid hydrogen and liquid deuterium

Using the cross-section model for neutron scattering in liquid H2 and D2, a neutron transport analysis is performed for spherical cold-neutron sources composed of either para H2, normal H2 or normal D2. A special effort is made to generate a set of energy-averaged cross-sections (80 group constants between 0.1 μeV and 10 eV) for liquid H2 and D2 at melting and boiling points. A number of conclusions on the spherical cold-neutron source configurations are drawn. It is especially shown that the highest cold-neutron flux is obtainable from the normal D2 source with a radius of about 50 cm, while the normal- and para-H2 sources with radii around 3-4 cm produce maximum cold-neutron fluxes at the center