On the Behavior of Interstitials Produced by Ionizing Radiation in Alkali Halides

The reactions occurring among radiation‐produced defects after the primary production step are the subject of this paper. For KCl, at liquid nitrogen temperature, the interstitial members of the radiation‐produced Frenkel defects are known to be mobile. A model that has been mentioned repeatedly in the literature is compared with experimental data. In the model, rate equations are used to describe radiation‐produced mobile interstitials which can either recombine with vacancies or can be trapped at other defect sites, causing the corresponding vacancies (F‐centers) to be stabilized. Asymptotic forms and analog computer solutions of simple forms of the equations are obtained. The experimental results include F‐center growth curves which are approximately linear with irradiation dose and which demonstrate that for a wide range of radiation intensities the F‐center production rate is proportional to the dose rate. The predictions of the model are in accord with experimental results only for a rather extreme asymptotic case, for which a different description, which does not require the solution of rate equations, may be equally valid.