On the buckling approximation for the angular distribution of neutrons in a slab lattice

Sn-calculations have been performed on a plane lattice with 13 cells, assuming one-speed neutrons scattering isotropically. Several orders of Legendre moments of the angular distribution have been evaluated at the cell centres and cell boundaries. The results agree with the buckling approximation, except close to the outer boundary of the system. The lowest asymmetric cell function has been calculated, both directly from the So data and through solving a transport equation. There is a slight difference between the results of the two methods, possibly caused by neglection of higher order buckling terms