DEFECT CREATION IN ALKALI-HALIDES UNDER DENSE ELECTRONIC EXCITATIONS - EXPERIMENTAL RESULTS ON NACL AND KBR

We present the results of simultaneous in situ luminescence and optical absorption studies of alkali-halides, submitted to very dense electronic excitations induced by swift heavy ion irradiations at low temperatures (15-200 K). X-ray irradiations performed in the same experimental conditions permit the necessary comparison with ion irradiations. The luminescence of the self-trapped excitons is only slightly modified by increasing the electronic stopping power, while new features appear for the point defect creation. For instance, in NaCl at 15 Y, F centres are efficiently created by Ne, Zn and Xe irradiations and F2 centres only by Zn and Xe irradiations. We discuss the evolution of the yields of defect Creation as a function of the temperature and of the electronic stopping power.