Radiation Transport Methods for Determining the Radiation Response from General Anisotropic Sources

摘要

Two radiation transport calculational techniques were developed which permit the study of radiation fields resulting from a broad class of source anisotropies important in weapon effects without having to perform transport calculations for each specific angle-energy dependent source. One method, limited to homogeneous air, uses adjoint one-dimensional ciscrete ordinated to calculate the importance of a particle's contribution to the fluence at various field points as a function of source emission angle. The radiation field is calculated, using this method, by integrating the product of the source function and the importance function over the 4 pi solid angle. The other, more general, method which can be used for air-over-ground, variable air density configurations and can include time and angular dependent flux, employs Monte Carlo to calculate moments of the fluence with respect to the polar angle of emission from the source. The coefficients of the power series expansion of a particular source anisotropy can then be folded with the moments to give the flux field for that source. (Author)