Penetration and Diffusion of X-Rays: Calculation of Spatial Distributions by Semi-Asymptotic Methods

Abstract

Methods are presented for calculating x-ray spectra in an infinite homogeneous medium. These methods are particularly useful for calculating spectra at great distances from the radiation source. The transport equation is solved numerically by characterizing angular and spatial distributions with a small number of suitable parameters. Attention is called to a mathematical technique which is extremely useful for this purpose, whereby a function may be approximated from a knowledge of moments, derivatives, or values. Sample numerical applications include spectral intensities at various distances from a plane monodirectional 10.22-Mev x-ray source in Pb and a plane monodirectional 5.11-Mev source in Fe.