Vi. Dubinko et al., Effect of dose rate, temperature and impurity content on the radiation damage in the electron irradiated NaCl crystals, NUCL INST B, 166, 2000, pp. 561-567
The dependencies of void formation and radiolytic sodium accumulation on th
e irradiation dose, dose rate, temperature and impurity content are analyze
d within a framework of a theoretical model, which is based on a new mechan
ism of dislocation climb. The mechanism involves the production of V-F cent
ers (self-trapped hole neighboring a cation vacancy) as a result of the abs
orption of excess H centers at dislocation lines. Voids are shown to arise
due to the reaction between F and V-F centers at the surface of halogen bub
bles. All reactions involved in the evolution of extended defects are contr
olled by the difference between the absorption of H centers and F centers.
This difference is determined by the material specific parameters responsib
le for the bias factors of extended defects and by the mean concentration o
f point defects. The latter depends on the temperature and dose rate as des
cribed in the present paper. Impurities can facilitate or suppress radiatio
n damage formation depending on their effect on the nucleation of extended
defects under irradiation. This is demonstrated by comparing theoretical re
sults obtained for dose dependence of colloid volume fraction at different
dislocation densities with experimental data obtained in crystals doped wit
h different impurities. (C) 2000 Elsevier Science B.V. All rights reserved.