A New Direct Point Flux Monte Carlo Estimator Using Compensated Rotational Symmetry

We describe a new formulation of the Monte Carlo approach to particle transport problems by defining a direct point flux estimator that extracts information from “passage” points rather than “collision” points. The approach leads directly to the radically new concept of track rotation and provides a statistical framework in which it is possible to prove the validity of the track rotation concept in spherically symmetric configurations and the validity of the compensated track rotation concept in nonspherically symmetric configurations. The approach can lead to essentially infinite gains in efficiency over conventional analog Monte Carlo methods that cannot directly estimate the flux at a point.