Pulse cathodo- and thermoluminescence of alumina ceramic with manganese

Alumina ceramics with manganese in concentration range 0.001-18 wt. % are synthesized. Luminescent properties of obtained ceramics at temperatures 1500-1700°C of sintering in vacuum are investigated. An increase in the manganese concentration leads to quenching of the pulse cathodoluminescence band at 420 nm and the main dosimetric peak at 460 K. The intensity of luminescence in the 676 nm band at manganese concentrations of more than 1 wt. % and the TL yield for all the observed peaks increase when annealing temperature rises. Sublinear increase in TL intensity with a growing dose is observed in the range of 3-1000 Gy in 460 and 620 K peaks. © Published under licence by IOP Publishing Ltd.The reported study was funded by RFBR according to the research project № 18-33-00085

Synthesis, Characterization and Luminescent Properties of Mg- and Cr-Doped Alumina Ceramics

The reported study was funded by RFBR according to the research project No 18-33-00085

Synthesis, characterization and luminescent properties of Mg- A nd Cr-doped alumina ceramics

Alumina ceramic doped with Mg and Cr is produced at high-temperature sintering under vacuum at varying annealing temperature and dopant concentration. A differential thermal analysis, X-ray fluorescence, and X-ray diffraction methods are used for sample characterization. The effect of the characteristics described above on the formation of different defects and luminescence centers in the samples was studied with a thermoluminescence method. An increase in the dopant concentration leads to an increase in the pulsed cathodoluminescence intensity of the dopant center in Mg-doped alumina ceramics and a decrease in Cr-doped alumina ceramics. The thermoluminescence intensity for Al2O3:Mg ceramics increases with magnesium concentration growth. The highest thermoluminescence intensity under a pulsed electron beam was obtained for ceramics with chromium (0.1 wt. %) annealed under vacuum at the temperature of 1500 °C for 2 hours. On thermoluminescence curves, one isolated peak at a temperature in the range of 645-665K was registered. © 2020 Author(s).The reported study was funded by RFBR according to the research project No 18-33-00085

Laminar-turbulent transition in Raman fiber lasers:a first passage statistics based analysis

Loss of coherence with increasing excitation amplitudes and spatial size modulation is a fundamental problem in designing Raman fiber lasers. While it is known that ramping up laser pump power increases the amplitude of stochastic excitations, such higher energy inputs can also lead to a transition from a linearly stable coherent laminar regime to a non-desirable disordered turbulent state. This report presents a new statistical methodology, based on first passage statistics, that classifies lasing regimes in Raman fiber lasers, thereby leading to a fast and highly accurate identification of a strong instability leading to a laminar-turbulent phase transition through a self-consistently defined order parameter. The results have been consistent across a wide range of pump power values, heralding a breakthrough in the non-invasive analysis of fiber laser dynamics

OPTICAL PROPERTIES OF ALUMINA CERAMIC DOPED BY YTTRIUM

The luminescence glow curves of ceramics based on aluminum oxide with impurities yttrium were investigated. A position and a shape of cathodo- and thermoluminescence peaks depend on the annealing temperature and the concentration of dopants.Исследование выполнено за счет гранта Российского научного фонда (проект № 18-72-10082)

THERMOLUMINESCENCE OF ALUMINA CERAMIC DOPING METAL IMPURITIES

Thermoluminescence of ceramic samples of aluminum oxide doped with chromium, magnesium and manganese impurities was measured. It is established that three luminescence bands appear in ceramics with impurity of manganese in the thermolumines-cence curve in comparison with two bands in a pure sample. It is shown that the lower the impurity concentration, the more intense the bands with maxima at 120 and 160 ºC.Работа выполнена при поддержке стипендии Президента Российской Федерации молодым ученым и аспирантам, осуществляющих перспективные научные исследования и разработки по приоритетным направлениям модернизации российской экономики (№ СП-3858.2018.2)

THE CALCULATION OF PRESURE PARAMETERS OF NANOSTRUCTURED ALUMINIA POWDER

The relative densities for different densities of compacts are calculated. The corresponding values of the pressing pressure are found. The optimal values of pressing parameters for compact creation of a given size and density are determined

STUDY OF OPTICAL PROPERTIES OF YTTRIUM OXIDE DOPED BY LITHIUM

Samples of yttrium oxide doped by lithium were synthesized in air at tem-peratures of 1200-1600оС. The spectra of thermoluminescence and cathodoluminescence were measured.Исследование выполнено за счет гранта Российского научного фонда (проект № 18-72-10082)

THE SYNTHESIS OF THE LUMINESCENT ALUMINA CERAMIC DOPED WITH MAGNESIUM

Samples of alumina ceramic doped with magnesium are manufactured at different temperature. An increase in the annealing temperature to 1200 ° C leads to the appearance of a luminescence peak at 520 nm, corresponding to the emission of magnesium spinel. The effect of annealing temperature and impurity concentration on the luminescence of alumina ceramics