Energy Dissipation near an Interface: A More Realistic Approach to Electron Range and Stopping Power

Spencer's (1) treatment of the energy dissipated near point isotropic electron sources is incorporated into the convenient formalism introduced by Charlton and Cormack (2) in their treatment of the interface problem. This approach leads to functions which are dependent both upon the initial electron energy and the medium in which the energy is being dissipated-factors not introduced into prior treatments (2-4). Dose distributions based on the functions derived in this paper are compared to distributions calculated from data presented by other authors. These comparisons suggest that dose distributions predicted by some of the simpler models of electron passage through matter are remarkably good and that one of the frequently-referred-to models must be rejected as a basis for dosage calculation. Functions are presented in tabular and graphical form for plane and spherical interfaces for electrons with high and low initial energies traveling through various media.