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1.
The results of a study of thermostimulated luminescence and recombination processes in pure and impure single crystals of BeO are reported. The origin of the trapping and recombination centers, their parameters (activation energies, frequency factors), the recombination schemes and the TL spectra were determined. It was shown that, in the BeO single crystals during electron and hole recombinations, the excitation of the intrinsic luminescence band at 4.9 eV proceeds and its characteristics inherit no properties from the recombination centers. 相似文献
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Optically Stimulated Luminescence (OSL) signals of BeO ceramics were investigated using continuous wave (CW) OSL and Linearly Modulated (LM) OSL. It was found that both curves can be approximated using a linear combination of two first-order components. Experiments on the measurement temperature dependence have shown that these two components have nearly the same thermal quenching energies around 0.57 eV. Dependences of the OSL signal on preheat temperature and radiation dose were also examined. Thermal annealing experiments have shown that OSL signals originate from traps which are unstable near 340 °C, thus proving the suitability of the signals for dosimetric purposes. Dose response was found to be linear and a minimum detectable dose of ~10 μGy was found. 相似文献
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B. V. Shul'gin A. V. Kruzhalov I. N. Ogorodnikov L. V. Viktorov V. A. Maslov C. Alexander D. W. Cooke 《Journal of Applied Spectroscopy》1988,49(2):848-852
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 49, No. 2, pp. 286–291, August, 1988. 相似文献
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The high-energy part of the blue fluorescence of-SiC(6H) is found to be dependent on the nitrogen (donor) concentration. The line fluorescence spectrum is found to include a new series of lines due to radiative transitions to A1 acceptor levels.We are indebted to J.G. Pichugin for providing the crystals. 相似文献
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The thermally stimulated currents (TSC) in InSe single crystals are investigated as a function of initial temperature T0 at which the samples examined are excited. In particular, experiments show that the peak at low temperature increases considerably in height and shifts markedly to lower temperatures as T0 is reduced. A kinetic model is proposed for the interpretation of the results. 相似文献
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Eduardo G. Yukihara 《Radiation measurements》2011,46(6-7):580-587
The objective of this work is to investigate basic luminescence properties of BeO optically stimulated luminescence (OSL) detectors, including the OSL emission and stimulation spectrum, the lifetime of the luminescence centers contributing to the OSL signal, and the temperature dependence of the luminescence lifetime and of the luminescence efficiency. The OSL stimulation spectrum shows a continuous increase in OSL intensity with decreasing stimulation wavelength. The emission spectrum indicates two OSL emission bands at ~310 nm and ~370 nm, the latter being the dominant OSL emission band. We also observed that the luminescence centers associated with the OSL signal are strongly quenched above room temperature, resulting in a reduction in luminescence lifetime from ~27 μs at room temperature down to ~800 ns at 140 °C. The activation energy for non-radiative decay of the luminescence center was determined to be E = (0.568 ± 0.023) eV. The ~27 μs luminescence lifetime observed for BeO indicate that POSL technique may be used to improve the signal-to-noise ratio using stimulation pulses of the order of microseconds. The information obtained in this study may help further optimize the BeO dosimetry systems and provide guidance on the timing parameters to be used for POSL measurements of this material. 相似文献
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《Radiation measurements》2007,42(4-5):742-745
Beryllium oxide (BeO) crystals were investigated by time-resolved low temperature VUV-spectroscopy at the SUPERLUMI station and BW3 beam line of HASYLAB (DESY, Hamburg). Photoluminescence spectra (3–10.5 eV), luminescence decay kinetics upon selective photoexcitation, as well as luminescence excitation (50–650 eV) and reflectivity (9–35 eV) spectra were measured and analyzed for oriented BeO crystals. It was shown that study of oriented crystals makes the traditional time-resolved spectroscopy method essentially more informative. Formation of the self-trapped exciton excited states of different multiplicity was found to sensitively depend on excitation energy and mutual orientation of the crystal's C optical axis and electric vector E of exciting polarized synchrotron radiation. 相似文献
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Results from spectral studies of the optical and luminescent properties of single crystals of lithium fluoride grown using the Czochralski technique and doped with ions of copper and magnesium, are presented. The effect of heat treatment regimes and the dependence of the concentration of magnesium impurities on the sensitivity of crystals of LiF:Mg, Cu to ionizing radiation are discussed. 相似文献
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The uncertainty about the existence of quasi-equilibrium (QE) condition during the readout of thermoluminescence and thermally stimulated conductivity glow peaks in real materials causes doubts about the validity of applying the QE-based analytical expressions to analyse these glow peaks. In this paper a simple method is given to verify the QE condition during the readout of these glow peaks in real materials. The method is based on changes in the glow peak shapes caused by changing the heating rate in non-QE cases. It is illustrated by using synthetic glow peaks derived from two different physically meaningful models. 相似文献
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A. Barrera-Villatoro T. Rivera-Montalvo V. Correcher J. Garcia-Guinea J. Zarate-Medina 《光谱学快报》2018,51(1):22-26
Cathodo- and thermoluminescence emission of calcium phosphates, synthetized by chemical precipitation and characterized by X-ray diffraction, environmental scanning electronic microscopy and energy dispersive spectroscopy have been studied. Thermal treatment at 1100°C increases the crystallinity, a phase transition (hydroxylapatite + β-tricalcium phosphate → β-tricalcium phosphate) and an enhancement of the luminescence emission. Cathodoluminescence and thermoluminescence display a very complex spectra in the UV–IR range where the wavebands would be associated with the presence of (i) hydroxyl groups, (ii) nonbridging oxygen hole centers, (iii) excited oxygens, (iv) peroxy groups, and (v) residual iron ions in the lattice. 相似文献
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The kinetics of thermally stimulated emission (TSL) from XB2O4 (X= Ca, Sr, Ba) has been investigated employing both isothermal decay and peak shape analysis methods. For BaB2O4 the emission was observed to lie in the visible region and the kinetics of TSL emission could be determined without any ambiguity. However, the emission spectra of CaB2O4 and SrB2O4 were found to consist of two broad emissions: one in the UV and the other in the blue green regions. Consequent to the presence of two emission bands, the determination of TSL kinetics required collection of TSL data for the two components of emission separately. Otherwise, an unambiguous determination of the TSL kinetics just could not be possible. The kinetics of TSL emission for the three borates is found to be of second order. 相似文献
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Pure nanocrystalline ZnO thermoluminescent phosphor was synthesized by chemical co-precipitation method. The prepared sample
was characterized by XRD, SEM and FTIR. The powder samples when exposed to X-irradiation showed that the thermoluminescence
response increases linearly with the increase of the time of X-irradiation. The glow curve exhibited two maxima centered at
116 and 207°C. The latter glow peak displays greater stability and sensitivity when the phosphor is exposed to X-irradiation
at room temperature. The results indicate that this new ZnO phosphor is a promising detector and dosimeter for X-irradiation. 相似文献
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Natural fluorite (CaF2), a dosimetric material of large usage, presents Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL). This study examined the behavior of TL and OSL (stimulated with Blue LEDs) signals from the Brazilian natural fluorite pellets with NaCl as binding agent, as well as their correlations, in order to study and optimize the dosimetric process with this material. A series of experiments were conducted, basically with thermal treatments before OSL acquisition, and optical bleaching before TL readout. The role of NaCl in the TL and OSL emission was investigated. It was observed that natural CaF2 TL signal is still ample to be used in dosimetric applications, as dose re-assessment in personal dosimetry after an OSL measurement. Also it was verified that the fluorite OSL signal is extinguished by a 350 °C heating and that NaCl has no contribution to the stable part of the OSL signal. 相似文献
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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.__________Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 1, pp. 140–142, January–February, 2005. 相似文献
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A study of specific features in the kinetics of thermoluminescence (TL) of defective α-Al2O3 crystals is reported. The TL properties are experimentally shown to be related to the presence of oxygen vacancies of thermochemical
or radiation origin. It is established that the differences in the TL kinetics in α-Al2O3 samples grown under different conditions can be accounted for by the hypothesis that the energy spectra of the trapping levels
have different widths. As is demonstrated with a titanium impurity, this broadening of the energy spectrum can originate from
the presence of traces of native impurities in the α-Al2O3 lattice.
Fiz. Tverd. Tela (St. Petersburg) 39, 1538–1543 (September 1997) 相似文献
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I. Kudryavtseva A. Lushchik A. I. Nepomnyashchikh F. Savikhin E. Vasil’chenko Yu. Lisovskaya 《Physics of the Solid State》2008,50(9):1667-1670
A coordinated study of the relaxation of optical absorption induced by vacuum ultraviolet radiation, x-rays, and α-particles, as well as of photo- and thermostimulated luminescence (TSL) of LiF : Mg, Ti crystals (TLD-100) in the 295–750-K interval, has revealed that TSL regions characterized by activation energies E a = 2.2–2.4 eV and anomalously high frequency factors p 0 = 1021–1022 s?1 alternate with regions where E a = 1.5 eV and p 0 = 1012–1014 s?1. The relative intensities of the TSL peaks produced by UV illumination (10–17 eV) differ strongly under the conditions of selective photon-induced generation of anion excitons, free electrons and holes, or near-impurity electronic excitations. The latter are responsible for the high efficiency of tunneling radiative (involving titanium centers) or nonradiative (involving hydroxyl ions) recombination. The analysis of TSL peaks of LiF: Mg, Ti and LiF took into account two-step processes, namely, thermal dissociation of three-fluorine F 3 ? molecules and recombination of the products of their decay (V K and V F centers, H interstices). 相似文献