DISCRETE DEPOSITION OF ENERGY BY ELECTRONS IN GASES

Much previous work on the energy deposition of electrons in gases has centered on the continuous-slowing-down approximation, the key element being the loss function -(1n)dEdx. Calculations generally reduce to energy integrals involving cross sections and this loss function. The limits of the continuous approximation are now examined by comparing it over various energy intervals with a method which takes into account the discrete nature of the energy lost in each collision. The calculation at each stage considers how an electron at a particular energy will redistribute itself on average at all lower energies, with the distribution depending on cross sections and transition energies. Results of the present work for He and N2, and comparisons to the continuous approximation, are given. © 1969 The American Physical Society.