Optically Induced Effects in the Thermoluminescence of Dosimetric Anion-Defective Corundum Crystals

Кортов, В. С.; Milman, I. I.; Moiseikin, E. V.; Nikiforov, S. V.

doi:10.1023/b:japs.0000032883.63709.e5

Cited by 3 publications

(9 citation statements)

References 5 publications

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“…We see that with an increase in the UV exposure time, the intensity of thermoluminescence at the dosimetric peak increases. This result is quite consistent, since as the deep traps are filled, there is an increase in the number of charge carriers captured by the dosimetric traps, which confirms that interaction occurs between the dosimetric and deep traps [5,9].…”

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Characteristic features of thermoluminescence kinetics in dosimetric aluminum oxide crystals

Кортов¹,

uulu²,

Vainshtein³

2006

J Appl Spectrosc

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We have studied the thermoluminescence curves in the 420 nm band (F centers) and the 330 nm band (F + centers) within the temperature range of the dosimetric peak (T max = 450 K) in anion-deficient aluminum oxide crystals. Assuming general-order kinetics, we have analyzed the thermoluminescence decay curves on the rising and falling sides of the dosimetric peak, in samples with different degrees of deep trap filling. We have established differences in the order of the kinetics within different temperature ranges of the dosimetric peak.Introduction. The thermoluminescence and kinetic properties of anion-deficient aluminum oxide single crystals have been studied in connection with their application for ionizing radiation dosimetry [1][2][3][4]. However, so far there has been insufficient study of the nature of the active centers and the mechanism for thermoluminescence (TL) at the dosimetric peak at 450 K. We know [1, 2, 5] that within this peak we observe mainly luminescence of F centers (oxygen vacancies with two trapped electrons) and also a number of thermoluminescence features: a dependence of the intensity of luminescence for the F centers (420 nm) on the heating rate, a decrease in the average activation energy, superlinearity of the dose curve. Establishment of the role played in the indicated processes by deep trapping centers, the thermal ionization of which occurs at 730 K and 880 K, represents important progress. Deep trap filling is connected with the above-indicated characteristics, since it determines the competition for capture of charge carriers in the trap, which are responsible for the dosimetric peak. Data are available [6] indicating that this peak is not an elemental peak and that different luminescence mechanisms can be realized within its temperature range.We also know [2] that in the TL spectrum of the dosimetric peak there is a 330 nm component due to luminescence of F + centers (oxygen vacancies with one trapped electron). The concentration of F + centers can be varied by exciting the studied crystals with UV light in the absorption band for F centers (210 nm). In this case, the conversion F center → F + center occurs and the free electrons generated occupy traps, including deep traps [7,8].The aim of this work was to analyze the kinetic parameters of thermoluminescence within the temperature range of the dosimetric peak for irradiated crystals of anion-deficient α-Al 2 O 3 , taking into account the noted characteristics.Samples and experimental procedure. Samples (diameter 5 mm and thickness 1 mm) of nominally pure anion-deficient single crystals of α-Al 2 O 3 were grown under strong reducing conditions [1]. For the irradiation, we used a β radiation source based on the 90 Sr/ 90 Y isotopes, providing a test dose of 64 mGy at the sample location for 2 min.The TL curves were recorded using an MUM grating monochromator and an FÉU-39A photomultiplier. The monochromator was used to isolate the luminescence bands of the F and F + centers. The original samples were preannealed up to a tempera...

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confidence: 70%

Characteristic features of thermoluminescence kinetics in dosimetric aluminum oxide crystals

Кортов¹,

uulu²,

Vainshtein³

2006

J Appl Spectrosc

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“…The present work is a continuation of the investigations carried out in [5] and is devoted to the study of the relationship between OSL and TSL in crystals of anion-defective corundum.…”

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confidence: 88%

“…In [5], optically induced destruction of the thermal luminescence of a signal in dosimetric crystals of aniondefective corundum was investigated; however, the radiative channel of relaxation of the carriers released by light was not investigated.…”

Section: Introductionmentioning

confidence: 99%

“…The jist of the method of OSL is the optical ionization of the levels of capturing the charge carriers occupied during exposure to ionizing radiation and registration of the luminescence caused by recombination of released carriers at the luminescence centers. The OSL yield appears to be proportional to the absorbed radiation dose.The OSL and TSL properties of detectors based on anion-defective corundum crystals are closely interrelated, and therefore the mutual study of these properties is useful for developing the theory, technique, and practice of registration of radiations that use these phenomena.In [5], optically induced destruction of the thermal luminescence of a signal in dosimetric crystals of aniondefective corundum was investigated; however, the radiative channel of relaxation of the carriers released by light was not investigated.The present work is a continuation of the investigations carried out in [5] and is devoted to the study of the relationship between OSL and TSL in crystals of anion-defective corundum.Experimental. We used samples of standard TLD-500 detectors that were developed at the Ural State Technical University-UPI [6]; the equipment employed is of Russian production.…”

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confidence: 99%

“…In studying the spectral-temporal dependences of optically stimulated depletion of the traps responsible for the main peak of TSL at 450 K in crystals of anion-defective corundum, it has been established that the maximum of the losses of the light sums stored in TSL is attained in the wavelength range 425-470 nm [5]. Here, the charge carriers (electrons) released into the conduction band generally can participate in the following events: capturing at shallow or deep traps and transitions to nonradiative or radiative recombination centers.…”

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Optically stimulated luminescence of dosimetric anion-defective corundum crystals

Milman¹,

Moiseikin²,

Nikiforov³

2005

J Appl Spectrosc

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The relationship between the characteristics of optically stimulated luminescence (OSL) and thermally stimulated luminescence (TSL) of dosimetric crystals based on nominally pure single-crystal, ion-defective corundum is considered. It is established that the TSL and OSL characteristics of these crystals are closely interrelated and are caused by the same active traps. It is shown that the OSL of deep traps has a form difficult to interpret, which can be due to the effect of both more shallow and deeper traps. Introduction.Optically stimulated luminescence (OSL) of the detectors of ionizing radiations (TLD-500) based on nominally pure single crystals of corundum with nonstoichiometric composition as to the oxygen sublattice (anion-defective corundum) has become an increasingly widespread method of registering ionizing radiations, whereas its physical and instrumental aspects are being actively investigated in the leading dosimetric laboratories of many countries [1, 2]. The basic advantage of the OSL-dosimetry over the traditional thermally stimulated luminescent (TSL) is the absence of heating and the associated problems of ensuring various and reproducible laws of raising the temperature and thermal quenching of luminescence that leads to the dependence of the TSL yield on the rate of heating of a detector [3,4]. The jist of the method of OSL is the optical ionization of the levels of capturing the charge carriers occupied during exposure to ionizing radiation and registration of the luminescence caused by recombination of released carriers at the luminescence centers. The OSL yield appears to be proportional to the absorbed radiation dose.The OSL and TSL properties of detectors based on anion-defective corundum crystals are closely interrelated, and therefore the mutual study of these properties is useful for developing the theory, technique, and practice of registration of radiations that use these phenomena.In [5], optically induced destruction of the thermal luminescence of a signal in dosimetric crystals of aniondefective corundum was investigated; however, the radiative channel of relaxation of the carriers released by light was not investigated.The present work is a continuation of the investigations carried out in [5] and is devoted to the study of the relationship between OSL and TSL in crystals of anion-defective corundum.Experimental. We used samples of standard TLD-500 detectors that were developed at the Ural State Technical University-UPI [6]; the equipment employed is of Russian production. OSL was measured by an FE ′ U-142 photoelectronic multiplier. To separate the stimulating light with the wavelength 470 nm from the luminescence in the 420-nm region a UFS-2 glass optical filter was installed between the sample and the photoreceiver.An SDK-S469-5-10 "superluminous" diode with a light strength from 3500 to 5000 mcd with a radiation wavelength of 470 nm and a halfwidth of about 10 nm was the source of optical stimulation. A continuous regime of stimulation at the selected geometry "in transmitte...

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Effects of neutron irradiation and subsequent annealing on the optical characteristics of sapphire

Zhang¹,

Zhang²,

Han³

et al. 2011

Physica B: Condensed Matter

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Optically Induced Effects in the Thermoluminescence of Dosimetric Anion-Defective Corundum Crystals

Cited by 3 publications

References 5 publications

Characteristic features of thermoluminescence kinetics in dosimetric aluminum oxide crystals

Characteristic features of thermoluminescence kinetics in dosimetric aluminum oxide crystals

Optically stimulated luminescence of dosimetric anion-defective corundum crystals

Effects of neutron irradiation and subsequent annealing on the optical characteristics of sapphire

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