Radiation-induced vacancy aggregation modes and radiation changes in optical and scintillation properties of insulator crystals

The mechanism of radiation changes involves both the formation of vacancy c lusters (pores) from photoproduced vacancies and the optical manifestations of pores. The growth of pores is controlled by dislocations (serving as si nks for interstitials generated simultaneously with vacancies). Depending o n dislocation density, the total surface of growing pores can vary with rad iation dose in quite different ways. This permits one to control crystal pr operties via a chosen regime of irradiation. Optically, radiation-produced pores manifest themselves as follows: 1) in excitonic absorption, which str ongly exceeds the absorption of usual color centers of the same concentrati on and can be used for estimating the concentration of pores and 2) via tra pping excitons inside the exciton band, thus enhancing intrinsic luminescen ce and diminishing the luminescence of the dope impurity. This paper presents a joint review of the above aspects of the vacancy clus ter physics which were developed separately in recent publications of the a uthors.