No abstract

~eatron pulse die-away experiments for small graphite assemblies by using a pulsed "cold" neutron source technique were carried out for the purpose to measure the pseudodecay·constants of trapped neutrons at the lowest Bragg-peak energy E 8 of coherent scattering in graphite, and also to estimate the temperature dependence of inelastic scattering cross section of neutrons at E 8 . Experiments were carried out for 77 and 19-!"K graphite systems with dimensions from 40x40x40cm 3 to 30x30x20cm 3 • The experimentally determined pseudo-decay-constants showed distinct temperature dependence and good agreement with the theoretical inelastic scattering cross sections by Young-Koppel model of phonon frequency distribution of graphite at these low temperatures.