Application of the ivon-mertens method to the solution of albedo problems in neutron diffusion theory

Abstract

Approximate albedo equations are formulated in which, in contrast to the diffusion approximation normally used, the approximate Ivon-Mertens method is applied, which involves an expansion of the angular dependence of the neutron flux at the boundary of two media for neutrons passing into and out of the medium. The results of these calculations indicate that this method gives a significantly higher accuracy than does the diffusion approximation. The albedo equations are formulated for a spectrum of slow neutrons reflected from media containing heavy atoms and formulae are obtained for the albedo and for the `temperature' of the reflected neutrons.