Neutron Wave Propagation Across a Temperature Discontinuity

Propagation of neutron waves across a temperature discontinuity in an infinite graphite assembly is investigated using a two-group approach. The first slab is assumed to be of finite width and the second is taken to be infinite. It is seen that the presence of the second medium is felt in the first medium at a larger distance from the interface for waves of smaller frequencies. In the second medium, equilibrium is established at a distance that depends on the frequency of the wave. It increases with the approach of critical frequency, becomes very large for frequencies greater than the critical frequency, and decreases with further increase in the frequency.