The transport of heavy charged particles produced by the 10B (n,α) nuclear reaction is predicted using a mean-range straight-flight model. The slowing down of these particles in a gas adjacent to the coating where they are born is described in terms of their flux energy spectrum, scalar flux, average energy, and energy-loss rate. These results are used in a plasma kinetics model which is compared to measurements of metastable excited state densities in helium and neon plasmas created by the heavy charged particles. The space-dependent fast primary electron (δ ray) energy spectrum produced by the heavy charged particles in helium is calculated, as well as the total number of fast primary electrons and their average kinetic energy.