Ion bombardment of alkali halides, IV: Production of f centers by positive ions and x-rays in KC1 and KCl(Tl)

This paper reports experiments on the suppression of F-center creation by thallium impurity in KC1 for irradiation by X-rays, protons, and alphas. It is found that impurity centers have a much smaller effect for charged-particle irradiation than for X-rays. This behavior is attributed to the high transient concentration of electrons and holes in the infratrack of a positive ion. This interpretation is supported by the observation of nearly equal F-center suppressions for different ions having the same initial velocity. In addition, the high F-center saturation concentration observed in pure KG by ion bombardment (∼1019 cm−3) is attributed to the high F-center production efficiency in the ion infratrack.