Penetration of High-Energy Electron Beams in Water

Abstract

The penetration, scattering, and absorption of electron beams of energy 10 to 20 MeV in water has been mathematically investigated by solving the Lewis equation by the moment method under the continuous slowing-down approximation. Two beam geometries were considered: plane infinite monodirectional beam and point monodirectional beam, both incident on an infinite water medium. For the former, expressions were obtained for the flux, current, rate of energy deposition, rate of charge accumulation, and angular distribution as a function of depth, taking into account not only the incoming primary electrons, but also the contribution of the secondaries. For the latter geometry, expressions were obtained for the root-mean-square average of the flux and energy deposition as a function of depth.