DOSE DEPENDENCES OF CREATION OF MAGNESIUM CENTERS IN LIF-MG CRYSTALS UNDER THERMAL-NEUTRONS

Dose dependences of the creation of F-, Mg+- and Mg-0-centres in LiF:M g crystals under thermal neutron irradiation have been studied experim entally and theoretically. Concentrations of the F- and Mg+-centres we re measured by optical absorption, and by photoluminescence for the Mg -0-centres. A model of a heavy charged particle track with a radial do se distribution generated by delta electrons was used for computing th e dose distributions in a thermal neutron track. The dose distribution in the irradiated crystal was calculated using convolutions of the do se distribution in single tracks. Mean concentrations of the centres w ere determined by integration of the yield at some point as a function of the local dose. The experimental dose dependences of the F- and Mg +-centres production are in good agreement with the calculations, but experimental points for the Mg-0-centres are regularly shifted from th e calculated curve. This effect, caused by the micromechanism of creat ion of this centre, is discussed.