TIME-LETHARGY EQUIVALENCE RELATIONS IN NEUTRON TRANSPORT THEORY.

The equivalent roles of the time and lethargy variables for the following infinite plane geometry transport problems are shown: (1) monoenergetic time-dependent neutron transport in an isotropically scattering homogeneous medium; (2) neutrons slowing down assuming a particular scattering kernel in a medium with constant cross section. This relationship is used to generate an analytic benchmark solution to which the S//N multigroup transport code ANISN can be compared. These results are relevant to nuclear reactors.