Average depths of electron penetration (II): angular dependence and use to evaluate secondary-electron yield by photons

In our previous paper [V. Lazurik, V. Moskvin and T. Tabata, IEEE Trans. Nucl. Sci. 45, pp. 626-631 (1998)] the average depth of electron penetration, [R.sub.av], has been introduced as the average of the maximum depths on the trajectories of electrons passing through a target. In the present work the dependence of [R.sub.av] on the angle of incidence of an electron beam has been studied. A semi-empirical equation is derived to calculate [R.sub.av] as a function of angle of incidence. We extend the study of [R.sub.av] from using it to characterize the average behavior of electron beams in a target to describing the generation of secondary electrons by photon beams. It is shown that [R.sub.av] can be used in a wide variety of applications in which the characteristic size of the spatial region of electron production is important.