Influence of lattice structure on the transport of thermal neutrons in beryllium

Transport of thermal neutrons in solid moderators is strongly influenced by the crystal structure. The case of neutron diffusion in finite blocks of beryllium is considered to bring out this dependence. It is shown that there is a strong build-up of cold neutrons as one moves away from the source and this is even larger in smaller assemblies. The angular distribution of neutrons scattered from beryllium slabs is also discussed. (author)