A Monte Carlo investigation of electron backscattering

Kearsley's, Haider's and Frujinoiu's cavity expressions depend upon the existence of reliable data on electron backscattering in different media. These data are not available in the literature. By using MCNP, backscatter distributions and their saturation values were obtained for electron beams with energies between 0.1 MeV and 9 MeV traversing different materials such as polyethylene, 'solid water', lithium fluoride, aluminium, copper and lead. The data obtained using MCNP show that electron backscatter probability most strongly depends on the scatterer's effective atomic number and electron energy. Backscatter probability becomes less dependent on energy and is mostly a function of the effective atomic number of the scatterer for electron energies below 0.5 MeV. For low atomic number materials MCNP data suggest that the back-scatter saturation values are distributed linearly with the effective atomic number of tire scatterer for all energies investigated.