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Abstract New Al 2 O 3 -BeO ceramics were synthesized from alumina nanopowder in BeO crucibles by high-temperature treatment in reducing conditions. It was found that the TL curve of these ceramics is characterized by a dosimetric peak at 520–530 K for a heating rate of 2 K/s. The integrated TL of the peak is not influenced by the heating rate of the samples, unlike that in anion-defective alumina and beryllia crystals. The presence of an energy distribution of the traps which cause dosimetric TL peak is verified by Tm-Tstop and initial rise methods. Linear dependence on dose of the intensity of TL peak at 520–530 K is observed in the 10–300 Gy gamma-dose range. The diversity of TL sensitivity of the ceramic samples synthesized in one cycle does not exceed 10%. The results obtained show that the newly synthesized Al 2 O 3 -BeO ceramics are promising materials for TL dosimetry of high doses of ionizing radiation. Highlights • New Al 2 O 3 -BeO ceramics were synthesized in vacuum in reducing conditions. • Dosimetric TL peak at 520 K is associated with trap depth distribution. • TL thermal quenching is not observed in Al 2 O 3 -BeO samples. • TL dose response in 520 K peak is linear from 10 to 300 Gy. [ABSTRACT FROM AUTHOR]

The influence of high-temperature annealing (900-1700 оС) on the morphological features, luminescent and dosimetric properties of ultrafine α-Al 2 O 3 ceramics obtained from nanopowder by its compaction has been studied. In contrast to previously published papers, for more reliable and unambiguous determining of the relationship between the nanocrystallite size and luminescent properties, the samples were annealed in air without a reducing agent. It has been established that at Т>1500 оС there is a significant increase in the intensity of thermoluminescence (TL) of the peak at 170 оС, which coincides with the temperature range of the most significant increase in the size of nanocrystallite. Another reason for the increase in the TL response may be the formation of luminescence centers during annealing, which is proved by the appearance of a new cathodoluminescence band at 2.2–3.4 eV of unknown nature. The analysis of the dose dependences of TL of nanostructured ceramics irradiated with a high-dose pulsed electron beam (130 keV, 1.5 kGy per pulse) reveals their sublinear nature. Moreover, anomalous TL fading has been found, the magnitude of which increases with a crystallite size. • The effect of annealing in air on TL of ultrafine α-Al 2 O 3 ceramics was studied. • TL intensity increases with the growth of the nanocrystallite size. • TL dose dependences in ceramics irradiated with pulsed electron beam are sublinear. • The anomalous TL fading was found, which increases with a crystallite size. [ABSTRACT FROM AUTHOR]

The luminescent and dosimetric properties of ultrafine MgO ≿eramics synthesized in strongly reducing conditions at Т = 1100–1400 °С are investigated. The growth of photo- and cathodoluminescence output at 2.0–3.5 eV (400–600 nm) is found. It is due to an increase in concentration of single oxygen vacancies and their aggregates. It was established that thermal treatment leads to TL intensity growth after high dose irradiation of the samples by a pulsed electron beam (130 keV). The tunneling mechanism of charge carriers' recombination occurs after this treatment as well. The presence of tunneling recombination is proved by the analysis of the shape and temperature dependence of TL isothermal decay curves. The possibility of using synthesized ceramics for high dose TL dosimetry of ionizing radiations is shown. [ABSTRACT FROM AUTHOR]

New Al 2 O 3 –BeO ceramics were synthesized by using high-temperature treatment of the initial compacts of nanostructured alumina in BeO crucible. The decomposition of the pulsed cathodoluminescence spectra into Gaussians revealed the luminescence bands related to oxygen vacancies and their aggregates in the ceramics. TL of the synthesized ceramics exposed to high-dose irradiation contained three peaks at 360 (A), 525 (B) and 730 K (C). It was found that optical stimulation at the wavelength of 470 nm causes optical bleaching of the traps responsible for peaks A and B, in contrast to the deep traps of the peak C, and gives rise to OSL. At the same time, there was a shift of the position of peaks A and B to the high-temperature region. This result shows the presence of the energy distribution of the traps responsible for TL peak A. It was found that the range of linearity of the TL dose response after gamma-irradiation is from 0.01 to 1.0 kGy. After irradiation with a pulsed electron beam (130 keV), the linear behavior of the OSL dose response was observed from 3 to 30 kGy. • The synthesis conditions affects the content, TL and PCL of Al 2 O 3 –BeO ceramics. • Emission centers in ceramics are formed by oxygen vacancies and their aggregates. • Irradiation with light at 470 nm causes optical bleaching of traps and OSL. • The traps of TL peak at 525 K are distributed along the energy depth. • TL and OSL of ceramics can be used for high-dose dosimetry (0.01–30 kGy). [ABSTRACT FROM AUTHOR]

A temperature growth and a decrease in impurity ion concentration result in a sensitivity increase of Al 2 O 3 :Mn ceramics to the ionizing radiation. The highest sensitivity to the ionizing radiation for Mn-doped alumina ceramics is observed for minimum dopant concentration and a maximum of temperature sintering (maximum sintering temperature). A sublinear increase in a thermoluminescence intensity with a growing dose is observed in the range of 1–400 Gy for the peak at 460 K and in the range of 1–100 Gy for the peak at 620 K for the Mn-doped alumina ceramic (1 wt % of Mn in a solution) annealed under vacuum at the temperature of 1700°С for 2 h. • PCL intensity in 678 nm band (Mn4+) is the highest at 1700°С and 10 wt % of Mn at doping. • The sintering temperature growth is result in a sensitivity increase to irradiation. • The highest TL intensity is observed for Al 2 O 3 :Mn ceramics with a minimum Mn content. • A sublinear dose response is observed in the range of 1–400 Gy (β-source) at 460 K peak. [ABSTRACT FROM AUTHOR]