Penetration and Diffusion of Hard X-Rays through Thick Barriers. I. The Approach to Spectral Equilibrium

Abstract

When some of the secondary components of a complex radiation are barely softer than the primary, the process of formation and decay of these components alone governs the approach to equilibrium. It is then possible to determine the asymptotic trend of the total radiation intensity at great depths of penetration. Under broad assumptions, this trend is ${x}^{{K}_{0}}\mathrm{exp}(\ensuremath{-}{\ensuremath{\mu}}_{0}x)$.