An improved electron multiple-scattering distribution for Monte Carlo transport simulation

An improved electron multiple-scattering distribution is presented in the form of a composite function which combines three expressions valid over different scattering angle regions: a modified relativistic Mott single-scattering term for large angle scattering, a modified Moliere Gaussian term for small angle scattering, and an exponential term for the intermediate angle scattering region. The exponential term has two adjustable parameters which make possible the smooth transition from the large to the small scattering angle regions. The proposed distribution exhibits better agreement with experiment than other multiple-scattering distributions commonly used in Monte Carlo electron transport codes, is amenable to direct sampling over a continuous range of electron energies and step sizes, can be used for elements of any atomic number, and is particularly suitable for use on small memory computers.