Composition nanodefects in doped lithium fluoride crystals

Лисицына, Л. А.; Лисицын, В. М.

doi:10.1134/s1063783413110139

Cited by 34 publications

(12 citation statements)

References 9 publications

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“…Since the color centers annihilate in time, the induced transient optical absorption may affect the emission decay kinetics due to destruction of the centers and decreased absorption since the spectral regions of the emission and absorption are overlapped. Note that in LiF-WO 3 crystals complex the color centers are formed more efficiently at low irradiation doses than those in ''pure'' LiF crystals since vacancies, interstitial ions and oxygen, hydrogen and OH ions enter the crystal with the dopant to compensate for excess charges and to relieve local stresses [14]. Fig.…”

Section: Resultsmentioning

confidence: 99%

Two possible causes of the stage of emission buildup after excitation by a nanosecond electron flux pulse

Лисицын¹,

Лисицына²,

Karipbayev³

et al. 2015

Optical Materials

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Section: Resultsmentioning

confidence: 99%

Two possible causes of the stage of emission buildup after excitation by a nanosecond electron flux pulse

Лисицын¹,

Лисицына²,

Karipbayev³

et al. 2015

Optical Materials

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“…Tungstates of metals of the second group belong to the so-called self-activating crystals in which the crystal lattice component in the form of the WO 6 oxyanion located in the regular lattice [1, 2] or near the crystal lattice defect represents a luminescence center according to [3,4].…”

Section: Results Of Investigationsmentioning

confidence: 99%

Effect of Thermal Treatment on the Scintillation Properties of ZnWO4 Crystals

2015

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Results of investigations into the scintillation properties of ZnWO 4 crystals with different prehistory are presented. A model of the processes leading to a dependence of the luminescence intensity on the depth of penetration of exciting radiation into the material is suggested.Currently ZnWO 4 scintillators are widely used as radiation detectors due to their high light yield, low level of natural radioactivity, high density, and non-hygroscopicity. To determine the chemical activity of the crystals, we investigated the effect of thermal treatment in an oxygen atmosphere on the characteristics of photo-and cathodoluminescence of ZnWO 4 crystals. The urgency of the research is determined by the need to predict changes in the crystal light yield during long-term operation in different temperature regimes.Stationary measurements of the luminescence excitation spectra in the range 6.2-2 eV were performed using an SM-2203 spectrofluorimeter at the Eurasian National University (Astana, Kazakhstan). The luminescence spectra of ZnWO 4 crystals with nanosecond temporal resolution 10 1 -10 5 ns after the termination of the excitation pulse were studied for crystals excited by laser radiation with photon energy of 4.66 eV or by the flux of electrons with energy of 250 keV. The spectra were recalculated considering the PMT sensitivity. RESULTS OF INVESTIGATIONSTungstates of metals of the second group belong to the so-called self-activating crystals in which the crystal lattice component in the form of the WO 6 oxyanion located in the regular lattice [1, 2] or near the crystal lattice defect represents a luminescence center according to [3,4].A laser with quantum energy of 4.66 eV (the region of the absorption exciton in the ZnWO 4 crystals according to [1]) excites the luminescence whose decay kinetics has short-and long-lived components with different spectral compositions (Fig. 1). The spectrum of the short-lived luminescence component consists of the asymmetrical band in the region of 3.6 eV with the decay constant ≤20 ns. The spectrum of the long-lived luminescence consists of the band at 2.5 eV whose decay can be described by the sum of three exponential functions with the same spectral compositions and values of the decay constant of 200 ns and 3 and 25 µs at 300 K.It was found that the ratio of the amplitudes of the short-lived (J 1 ) and long-lived bands (J 2 ) in the luminescence spectrum (J 1 /J 2 ) depends on the two parameters: the state of the crystal surface and the method of luminescence excitation. Thus, the ratio of the band amplitudes excited by laser radiation with quantum energy of 4.66 eV in crystal after thermal treatment at 900°C in the oxygen atmosphere increased by two orders of magnitude compared with the value of this ratio for the crystal just cleaved from a monoblock. However, the ratio J 1 /J 2 for the

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“…It means that intrinsic emission arises due to the spin-forbidden transition from the triplet state of the self-trapped exciton localized at the regular (WO 6 ) 6À oxyanion complex. An alternative interpretation of the luminescence in these materials is reported in [10][11][12], where it is suggested that high light yield of emission is caused by material imperfections due to the impossibility to maintain stoichiometry of the melt during growing.…”

Section: Methodsmentioning

confidence: 94%