Slowing-down spectra of neutrons in heavy water and light water mixtures

Abstract

The slowing down spectra of neutrons are obtained for heavy water, light water, and mixtures of heavy water and light water. It is assumed that fission neutrons are produced uniformly throughout an infinite moderator and the only process considered is elastic scattering, spherically symmetric in the centre of mass system. The (n, 2n) reaction with the deuterium nucleus and absorption are assumed negligible. The average transfer cross section, fast diffusion coefficient, the slowing down area, and average velocity ratio are obtained for two—group calculations using the epi — thermal spectra.