Some Results on the Energy-Dependent Milne Problem for Thermal Neutrons and Light Gases

We have studied the thermal-neutron flux near the boundary of a semi-infinite non-absorbing gas which scatters neutrons isotropically. The THERMOS code was used to obtain numerical solutions to the integral transport equation. The properties of the flux, integrated over all energies, at the surface of the semi-infinite medium were found to be very insensitive to variations in the scattering properties of the medium.