Placzek-Type Oscillations in General Neutron Slowing Down

Placzek proved that the collision density of neutrons coming from an energy point source and slowing down by isotropic elastic scattering in an infinite one-isotope nonabsorbing medium oscillates in a certain typical manner. It is proved in this paper that Placzek-type oscillations occur in one-isotope infinite media under the most general elastic scattering law and most general absorption law. In particular, the scattering need not be isotropic nor the absorption small or constant.