AP19178510 "Experimental and theoretical investigations of radiation-induced defects in BaFBr and BaF2 crystals"

- Oxygen impurities were observed in the studied BaFBr crystals irradiated with 147 MeV 84Kr ions and 25.5 MeV 14N ions and stored in the dark for a long time.

- it is shown that a wide complex band of radiation from 1.5 to 3.5 eV is present in the PL spectrum, which is also present in an unirradiated crystal, but with a lower intensity;

- with an increase in fluence to 1011 ions/cm2, an increase in the luminescence intensity of the centers of the first type (2.5 eV), the second type (2.05 eV) and the third (2.3 eV) was observed. The creation of the third type leads to a displacement of the maximum of the other two types of centers.;

- it was found that oxygen vacancy centers are formed not only during crystal growth, but also during BTI irradiation.

- macrodefects (hillocks and tracks) and aggregates significantly affect the luminescence of oxygen vacancy defects. The formation of hillocks and tracks in BaFBr crystals under irradiation with 147 MeV 84Kr ions has been shown for the first time. Hillocks can contribute to a decrease in luminescence intensity, especially with increased fluence, due to light scattering.;

- significant amorphization of BaFBr crystals irradiated with high-energy krypton ions has been established from the RS analysis. PC analysis confirmed that BaFBr crystals were amorphized by 147 MeV 84Kr ions due to track overlap, in contrast to samples irradiated with 24.5 MeV 14N ions.

- Analysis of the absorption and Raman spectra of light samples irradiated with fast Kr ions showed the formation of electron and hole aggregates of point defects. Comparing with the results of the study of aggregate hole point defects in KBr, it can be assumed that the absorption band with a maximum of 4.5 eV is associated with the centers of 〖Br〗_3^- , and 5.5 eV with the di-H centers;

- The use of the PBE and HSE06 functionals, as well as the GW0 calculations in our DFT calculations, provided the basis for fast and accurate modeling of defects and their effect on the optical properties of the crystal.

Based on the analysis of the research results, it is possible to predict radiation resistance and degradation of materials. Modern IP is a material that contains BaFBr crystals, an inert base to irradiation, on which detecting particles are applied. Our research has made it possible for the first time to consider the mechanisms of radiation damage by optical and Raman spectroscopy and to investigate surface defects.