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40 results on '"Nikiforov, S.V."'

24. Luminescent and dosimetric properties of magnesium oxide ceramics synthesized by a high-energy electron beam

Author

null Ishchenko A.V., null Golkovski M.G., null Kasatkina Y.P., null Ananchenko D.V., null Lisitsyn V.M., and null Nikiforov S.V.

Abstract

For the first time, samples of magnesium oxide ceramics were obtained by a method based on irradiation of the oxide powders with a beam of fast electrons. Luminescence centers associated with intrinsic and impurity defects were found in the obtained samples. A comparative analysis of the thermoluminescence (TL) curves and dose dependencies of TL of MgO ceramics obtained by the radiation and thermochemical methods is carried out. The linear dose dependence of the TL peak at 370 K excited by a pulsed electron beam (130 keV, 1.5-30 kGy) is shown to be the main advantage of MgO ceramics for their use in TL dosimetry. Possible reasons for improving the linearity of the dose characteristics of the newly created ceramics in comparison with analogs are discussed. Keywords: magnesium oxide, thermoluminescent dosimetry, dose response, oxygen vacancies, pulsed cathodoluminescence.

Published
2022

30. Specific features of the thermoluminescence kinetics of shallow traps in anion-defective single crystals of aluminum oxide

Author

Kortov, V.S., Nikiforov, S.V., and Sadykova, E.Z.

Abstract

The kinetics of thermoluminescence (TL) arising from shallow traps in single crystals of anion-defective aluminum oxide has been considered. It has been shown that the TL peak at 320-350 К is characterized by identical kinetic parameters in samples containing various concentrations of shallow traps. Кinetic TL parameters for this peak have been calculated by analyzing of the luminescence isothermal decay curves, varying the heating rate, and the peak shape. An interactive relationship of shallow and dosimetric traps in the crystals under study has been supposed. Проведен анализ кинетики термолюминесценции (ТЛ), обусловленной мелкими ловушками в монокристаллах анион-дефектного оксида алюминия. Показано, что ТЛ пика при 320-350 К характеризуется идентичными кинетическими параметрами у образцов с различной концентрацией мелких ловушек. Рассчитаны кинетические параметры ТЛ этого пика методом анализа кривых изотермического затухания люминесценции, вариации скоростей нагрева и анализа формы пика. Высказано предположение о наличии интерактивной взаимосвязи мелких и дозиметрических ловушек в исследуемых кристаллах. Виконано аналiз кiнетики термолюмiнесценцiї (ТЛ), обумовленої мiлкими пастками в анiон-дефектних монокристалах оксиду алюмiнiю. Показано, що ТЛ пiка при 320- 350 К характеризується iдентичними кiнетичними параметрами для зразкiв з рiзними концентрацiями мiлких пасток. Обчислено кiнетичнi параметри цього пiка методами аналiзу кривих iзотермiчного згасання люмiнесценцiї, варiювання швидкостi нагрiвання та аналiзу форми пiка. Висловлено припущення про наявнiсть iнтерактивного взаємозв'язку мiлких та дозиметричних пасток у кристалах, що дослiджувалися.

Published
2005

38. DEEP-TRAP COMPETITION MODEL FOR TL IN α-Al2O3:C HEATING STAGE.

Author

Kortov, V.S., Milman, I. I., Moiseykin, E.V., Nikiforov, S.V., and Ovchinnikov, M. M.

Subjects
THERMOLUMINESCENCE, HOT carriers, ELECTRONS, HOLES (Electron deficiencies), ELECTRON transport, ALUMINUM oxide, CRYSTALS, HEATING, MATHEMATICAL models
Abstract

The present report deals with the experimental observations of the thermally stimulated migration of charge carriers from trapping centres responsible for the main thermoluminescence (TL) peak at 450 K to a deep trap and, also, the optically stimulated transport of carriers from the deep trap to the main trap, which gives rise to the phototransferred TL at 450 K, in anion-defective α-Al2O3 crystals. The obtained results provide an experimental proof to the adequacy of the assumptions made in the model of the mutual interaction of the main and deep traps in the crystals under study. [ABSTRACT FROM AUTHOR]

Published
2006
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39. Specific features of luminescence of radiation-colored <f>α</f>-<f>Al2O3</f> single crystals

Author

Kortov, V.S., Nikiforov, S.V., Milman, I.I., and Moiseykin, E.V.

Subjects
*LUMINESCENCE, *RADIATION, *CRYSTALS, *ALUMINUM oxide
Abstract

Results of a comparative study on specific features of luminescence of thermochemical and radiation-colored crystals of aluminum oxide have been described. It is shown that crystals containing oxygen vacancies of different origins have identical main optical properties. A vacancy or vacancy-impurity origin of deep traps has been assumed. Some specific features of thermoluminescence (TL), which are common for both types of crystals, such as the dependence of the TL output on the heating rate and the occupancy of deep traps described by the model of interactive trap system, have been established. [Copyright &y& Elsevier]

Published
2004
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40. Luminescence properties of <f>α</f>-<f>Al2O3</f> dosimetric crystals exposed to a high-current electron beam

Author

Milman, I.I., Moiseykin, E.V., Nikiforov, S.V., Mikhailov, S.G., and Solomonov, V.I.

Subjects
*LUMINESCENCE, *THERMAL dosimetry, *ELECTRON beams, *LIGHT sources
Abstract

The spectra of pulsed cathodoluminescence (PCL) and thermoluminescence (TL) in TLD-500 detectors, which were exposed to a strong beam from a pulsed electron accelerator, have been studied. Additional bands in the PCL spectrum and new peaks in the TL curves, which are due to impurity ions, have been revealed. Luminescence bands of F- and F+-centers cannot be used in the dosimetry of strong electron beams using TLD-500 detectors because of the saturation of dose dependence and the decrease in the TL yield. It is shown that high doses from these beams can be measured by recording TL in the luminescence band of impurity titanium ions. [Copyright &y& Elsevier]

Published
2004
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