Theoretical Analysis of Pencil Beams With Highly Forward Scattering

Abstract

A normally-incident and infinitely narrow beam of radiation impinges on a homogeneous material. As this beam penetrates the system, the particles in the beam undergo scattering and the beam broadens. Explicit expressions for the amplitude and the root-mean-squared radius of the beam, as a function of depth, are derived from the linear transport The analogous expressions are derived for the approximate diffusion solution, and the two results are compared.