A New Angular Biasing Scheme for Deep-Penetration Problem in 3-D by Monte Carlo

Abstract

A new biasing scheme for scattering kernel has been developed for three dimensional thick shield problem based on the zero-variance biasing scheme for reaction rate calculations. This scheme along with biasing of the space transition kernel results in reduction of variance by an order of magnitude over the standard exponential biasing scheme. Only one biasing parameter is involved for biasing both the space trcnsition, as well as the scattering kernel. A smiple recipe has been provided for obtaining this biasing parameter with the help of an estimated reaction rate integral. Calculations have been perfonned for a 20 m .f .p. thick shield with two different cross-section areas. Three different values of scattering probabilities have been considered in these calculations. A comparison between the present scheme aid the exponential biasing scheme has been presented.