0000000000354276
AUTHOR
Ch. Lushchik
showing 5 related works from this author
Influence of complex impurity centres on radiation damage in wide-gap metal oxides
2016
Different mechanisms of radiation damage of wide-gap metal oxides as well as a dual influence of impurity ions on the efficiency of radiation damage have been considered on the example of binary ionic MgO and complex ionic–covalent $Lu_{3}Al_{5}O_{12}$ single crystals. Particular emphasis has been placed on irradiation with $\sim$2 GeV heavy ions ($^{197}Au, ^{209}Bi, ^{238}U$, fluence of 10$^{12}$ ions/cm$^{2}$) providing extremely high density of electronic excitations within ion tracks. Besides knock-out mechanism for Frenkel pair formation, the additional mechanism through the collapse of mobile discrete breathers at certain lattice places (e.g., complex impurity centres) leads to the c…
Radiation creation of cation defects in alkali halide crystals: Review and today's concept (Review Article)
2018
Irradiation of alkali halide crystals creates pairs of Frenkel defects both in anion and cation sublattices. However, the particular nonimpact creation mechanisms (related to the decay of different electronic excitations) of cation Frenkel pairs are still unclear. At helium temperatures, there is yet no direct evidences of the creation of stable (long-lived) elemental cation defects. On the other hand, a number of complex structural defects containing cation vacancies and/or interstitials, were detected after irradiation of alkali halides at higher temperatures. Besides already proved mechanism related to the association of H and VK centers into trihalide molecules, the following possibilit…
Luminescence and EPR spectroscopy of neutron-irradiated single crystals of magnesium aluminium spinel
2016
Abstract Neutron irradiated single crystals of stoichiometric MgAl 2 O 4 and MgAl 2 O 4 :Mn 2+ (0.15 wt. %) were studied using the methods of luminescence spectroscopy and versions of electron paramagnetic resonance. In stoichiometric MgAl 2 O 4 :Mn 2+ single crystals, the transition of a part of manganese impurity ions from tetrahedral to octahedral coordination, caused by irradiation with fast fission neutrons, is detected using photoluminescence spectra. This fact confirms the partial inversion of a normal spinel due to neutron-irradiation. Using pulse EPR technique it is shown that an electron in the field of oxygen vacancy (i.e. from neutron-irradiation induced F + centres, which are s…
Luminescence of γ-radiation-induced defects in α-quartz
2004
Optical transitions associated with γ-radiation-induced defects in crystalline α-quartz were investigated by photoluminescence excited by both pulsed synchrotron radiation and steady-state light. After a 10 MGy γ-dose we observed two emissions at 4.9 eV (ultraviolet band) and 2.7 eV (blue band) excitable in the range of the induced absorption band at 7.6 eV. These two luminescence bands show a different temperature dependence: the ultraviolet band becomes bright below 80 K; the blue band increases below 180 K, but drops down below 80 K. Both emissions decay in a timescale of a few ns under pulsed excitation, however the blue band could also be observed in slow recombination processes and it…
UV cathodoluminescence of crystalline α-quartz at low temperatures
2004
Two luminescence bands in the UV range were detected in crystalline a-quartzunder electron beam excitation (6 kV, 3–5mA). One band is situated at 5 eV and could be observed in pure samples. Its intensity increases with cooling below 100 K and undergoes saturation below 40 K alongside a slow growth with the time of irradiation at 9 K. The decay curve of the band at 5 eV contains two components, a fast (o10 ns) and a slow one in the range of 200ms. The photoluminescence band at 5 eV with a similar temperature dependence was found in previously neutron-irradiated crystalline a-quartz. Therefore, the band at 5 eV was attributed to host material defects in both irradiation cases. The creation me…