Radiation field from a rectangular source

Abstract

Many radiation shielding problems involve calculations of the response of an isotropic detector to radiation of arbitrary angular distribution from uniform rectangular sources. In calculations of this type the family of integrals integral /sub s/(cos theta dS/r/sup 2/)P/sub 1/(cos theta ) and the integral integral /sub s/ (dS/r/s up 2/)exp(-- mu t/ cos theta ) are frequently encountered, where theta is obliquity with respect to an axis perpendicular to the plane containing the rectangular radiant surface. S, r is the distance from an element source area, dS, to the detector, mu is the attenuation coefficient, and t is the barrier thickness. Solutions of the first type of integral facilitate use of Regendre expansion representations of radiation directional distributions, and may also have application in other radiant surface studies, such as illumination and heat exchange engineering. The second integral relates to exponentially attenuated radiation from a plane isotropic rectangular source sepanated from the detector by a layer of material of thickness t. Formulas, expansions, and numerical results are presented. (autu)