Straggling of moderately relativistic electrons

A simple analytical model for computing range-energy straggling of moderately relativistic electrons is set up. Both inelastic scattering and bremsstrahlung are considered as sources of straggling. The model gives overestimates for radiative straggling, but it is indicated how this overestimation may be removed. The simple (overestimating) model is used to compute range straggling for electrons up to kinetic energies of 4 MeV in uranium and up to 30 MeV in aluminium. The occurrence of the infinities in Eyges' radiative straggling treatment are explained and removed. The results justify the neglect of straggling in electron transport when applied to photon production as done by Brown, Ogilvie, Wittry, Kyser, Ehrman, dePackh, and others.