Behavior of Ion Spurs and Tracks in Irradiated Dipolar Systems

Abstract

The problem of electron moderation and subsequent recapture or escape in irradiated dipolar substances is investigated theoretically. By considering the dielectric relaxation, the electric energy of a spur or track consisting of positive ions and diffusing electrons is evaluated. The moderation being fast as compared with the dielectric relaxation time, the energy content of the spur or track decreases due to an increase in the dielectric constant after the moderation has been completed. At the expense of this energy decrease, some thermalized electrons may diffuse away from the field of the positive ions if they are slow enough not to increase the spur energy faster than it is decreased by dielectric relaxation. The theory is tentatively applied to γ and α-irradiated water and ice and, while a substantial fraction of electrons is found capable of escaping in the liquid state, for the crystalline state complete recapture is predicted.