The Time Decay Constants in Neutron Thermalization

We examine herein the decay constants,λ_k which appear in the modal expansion of the neutron density in a study of the time-dependent thermalization of neutrons. A study of the proton gas moderator indicates the existence of an infinite number of discrete λ_k in the range . The upper limit is a limit point for the eigenvalue sequence. Consideration of more general models indicates the existence of a discrete spectrum in the range 0 min and max and a continuous spectrum in .