Book Description

Air-filled openings through weapons radiation shields (for example, ducts, passageways, etc.) can increase the total amount of radiation penetrating the shield, primarily as a result of radiation successively scattering from the walls of the openings. Most techniques that have been developed for estimating the transmission of radiation through such openings depend on the use of albedos, an albedo being the fraction of radiation incident on a surface that is reflected back out of the material, assuming that the radiation enters and emerges at the same point. This chapter of the Handbook surveys the work performed to date on the various types of nuclear radiation albedos and uses a consistent nomenclature which shows the relationship of the results obtained in the different studies. Since the material considered most often for weapons radiation shields is concrete, most of the albedo data are for this material, although some data have been obtained for other materials, particularly for soils. The data are reported as singly differential albedos (differential with respect to the emergent angle), doubly differential albedos (differential with respect to both the emergent energy and the emergent angle), and total albedos (albedos for which the data have been integrated over both the emergent energy and emergent angle). Three fundamental types of differential and total albedos are used: an albedo which represents an incident flux of particles and an emergent current of particles, an albedo which represents an incident current and an emergent current, and an albedo which represents an incident flux and an emergent flux. These fundamental albedos may be weighted by dose response functions or by energy.