OPTICAL STUDY OF DEFECTS IN RBI AND KI BOMBARDED WITH HIGH-ENERGY ARGON IONS AT TEMPERATURES BETWEEN 20 K AND 300 K

RbI and KI crystals have been bombarded with high energy argon ions at temperatures between 20 K and 300 K followed by an in situ measuremen t of the optical absorption. The defect inventory at each temperature has been studied. The efficiency of F centre production in its broad f eatures follows that observed using X-irradiation; the rate is low at 20 K and rises to a maximum at 200 K followed by a decrease at 300 K. The 20 K results for RbI also show the relatively small presence of H centres and di-interstitial halogen aggregates but also significant co ncentrations of alpha-centres and the complementary I-centres. The res ults are discussed in the light of the excitonic mechanism and the cur rent ideas concerning the deposition and dissipation of energy in the ion tracks. Micro-Raman spectroscopy has been used to study the concen tration profile of halogen aggregates along the ion tracks in samples bombarded at 300 K.