title: Accurate condensed history Monte Carlo simulation of electron transport. II. Application to ion chamber response simulations.
abstract: In this report the condensed history Monte Carlo simulation of electron transport and its application to the calculation of ion chamber response is discussed. It is shown that the strong step-size dependencies and lack of convergence to the correct answer previously observed are the combined effect of the following artifacts caused by the EGS4/PRESTA implementation of the condensed history technique: dose underprediction due to PRESTA'S pathlength correction and lateral correlation algorithm; dose overprediction due to the boundary crossing algorithm; dose overprediction due to the breakdown of the fictitious cross section method for sampling distances between discrete interaction and the inaccurate evaluation of energy-dependent quantities. These artifacts are now understood quantitatively and analytical expressions for their effect are given.
authors.affiliation: National Research Council, Ottawa, ON, Canada.
authors.forename: I
authors.initials: I
authors.lastname: Kawrakow
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D004579:Electron Transport; D008433:Mathematics; D008962:Models, Theoretical; D009010:Monte Carlo Method; D011874:Radiometry; D012542:Scattering, Radiation