Speaker
Anatoli Popov
(Institute of Solid State Physics)
Description
The radiation-resistant insulators (MgO, Al2O3, MgAl2O4, BeO etc) are important key materials for fusion reactors. It is very important to predict/simulate not only the kinetics of diffusion-controlled defect accumulation under neutron irradiation, but also a long-time defect structure evolution including thermal defect annealing. Here we developed and applied the advanced theoretical approach based on the formalism of the correlation functions suited much better for the study of defect kinetics and aggregation than generally accepted rate equations.
On the basis of our calculations, we estimated the migration energy of the F centers and interstitial oxygen defects Oi, their interaction energies and metal colloid size upon annealing. We simulated the F-type center annealing after electron, heavy ions or neutron irradiation as a bimolecular process with equal concentrations of the complementary F and Oi defects. It is controlled by the interstitial oxygen ion mobility, which is much higher than that of the F centers. The F center annealing begins at temperatures 500-700 K, when both F and F++ centers are practically immobile, due to the recombination with mobile Oi defects. It is demonstrated how the shape of the F-annealing curves is determined by two control parameters: Ea and effective pre-exponential factor and strongly depends on irradiation conditions.
The appropriate migration energies were obtained from available in literature annealing kinetics for electron, neutron and ion- irradiated oxide crystals (MgO, Al2O3, MgAl2O4, BeO, ZnO, PLZT etc). The results obtained are also compared with recent ab initio calculations of interstitial oxygen migration (MgO and Al2O4).
Co-authors
Aleksandr Lushchik
(Institute of Physics, University of Tartu, Tartu, Estonia)
Anatoli Popov
(Institute of Solid State Physics, University of Latvia, Riga, Latvia)
Eugene Kotomin
(Institute of Solid State Physics, University of Latvia, Riga, Latvia)
Rafael Vila
(CIEMAT, Avda. Complutense 40, 28040 Madrid, Spain)
Vladimir Kuzovkov
(Institute of Solid State Physics, University of Latvia, Riga, Latvia)
