On the condensed history technique for electron transport

Abstract In this report we discuss the theory of the “condensed history technique”, an approximate solution to the Boltzmann transport equation that sums the effect of up to thousands of discrete, small momentum transfer elastic and inelastic collisions into single larger-effect quasi-events. This technique saves much calculational effort at the expense of introducing errors that are now understood quantitatively in terms of the development presented herein. We apply our analysis to modern realizations of the condensed history method, namely those of EGS/PRESTA, ETRAN/TLC, FLUKA, PENELOPE, and LLCA. We have also constructed an algorithm that exhibits smaller large step size instabilities than all of these methods and give several examples.