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1.
V.L. Cherginets T.P. Rebrova T.V. Ponomarenko O.A. Tarasenko N.N. Kosinov O.V. Zelenskaya 《Radiation measurements》2012,47(10):917-920
The dependence of the scintillation properties of Ce3+-doped YCl3 and YBr3 on activator concentration (0.5, 1 and 2 mol%) has been studied. The radioluminescence spectra of both materials contain asymmetric bands with maxima located at 3.13 eV (383 nm) for YCl3:Ce3+ and 2.84 eV (422 nm) for YBr3:Ce3+. The scintillation pulse decay curves for both materials are described by two components with decay constants of 37 and 640 ns for YCl3:Ce3+ and 36 and 450 ns for YBr3:Ce3+, the fractions of the faster component being 86 and 79 per cent, respectively. The dependences of the light yield of the studied materials on Ce3+ concentration pass through a maximum near 1 mol% of the activator, and the maximum light yields (relative to NaI:Tl) are 8700 photons per MeV for YCl3:Ce3+ and 20,600 photons per MeV for YBr3:Ce3+. 相似文献
2.
Yuntao Wu Dongzhou Ding Shangke Pan Fan Yang Junyan Shi Guohao Ren 《Journal of luminescence》2012,132(2):251-255
Lu0.8Sc0.2BO3 crystals doped with 1 at%Ce3+ and co-doped 0.1 at% and 0.5 at%Pr3+ were grown by the Czochralski method. The concentrations of Pr3+ and Ce3+ in crystals were measured by the ICP-AES method. Absorption spectra, VUV–UV spectra, fluorescence decay time and X-ray excitation luminescence spectra were investigated at room temperature. The excitation luminescence spectra of Ce3+ emission and decay curves from the lower excited state levels of the 4f15d1 and 5d1 electronic configurations of the Pr3+ and Ce3+ conspicuously indicated the non-radiative energy transfer from Pr3+ to Ce3+. The detailed pathways were shown in the energy level diagram of the respective Ce3+ and Pr3+ in Lu0.8Sc0.2BO3 host. In addition, the scintillation efficiency data indicated that the energy transfer effect is directly associated with the Pr3+ concentration. 相似文献
3.
Eu2+:CeBr3 crystals were grown by vertical Bridgman growth method and slight aliovalent doping of Eu2+ in the CeBr3 crystal did not change the crystal structure. The X-ray stimulated luminescence, photoluminescence, decay kinetics and scintillation properties were investigated at room temperature. The X-ray stimulated luminescence spectra exhibited wide broad emission bands from 3.54 eV to 2.95 eV in the Eu2+:CeBr3 crystal with high content of 620 ppm of Eu2+, which were the overlap of the emission bands ascribed to 5d → 4f transition of Ce3+ and 4f65 d1 → 4f7 transition of Eu2+, respectively. When the content of Eu2+ was decreased to 70 ppm, another emission band centered at 2.29 eV was observed. The photoluminescence spectra showed the energy transfer from Ce3+ to Eu2+. This decreased the Ce3+ emission intensity but enhanced the Eu2+ emission intensity. The photoluminescence decay time of Ce3+ emission decreased from 14 ns to 10 ns when the content of Eu2+ increased from 70 ppm to 620 ppm. The decay time of the emission of 525 nm did not change with the excitation wavelength and Eu2+ content, which could be assigned to the excitons that were bound on Eu2+ related centers. The light output of the Eu:CeBr3 crystal under the excitation of 241Am radioactive source was less than 20.2% of Tl:NaI crystal. 相似文献
4.
本文采用垂直Bridgman法,分别生长了未掺杂LaCl3和掺有不同浓度CeCl3的LaCl3闪烁晶体,并对它们的透光性质、发光性质和光衰减特性进行了测试和对比分析.发现未掺杂LaCl3晶体的吸收边位于215 nm附近,本征发射峰为405 nm,衰减时间在1μs以上.该发光属于纯氯化镧晶体的自陷激子发射,但随着CeCl3掺杂浓度的提高,源于自陷激子(STE)的本征发射强度逐渐降低,LaCl3:Ce晶体中的吸收边逐渐红移至300nm,由Ce3+中心所产生的5d→4f发射逐渐增强,其衰减时间加快至~20 ns.这种现象被解释为LaCl3晶格中的自陷激子向Ce3+离子发光中心的能量传递作用所致. 相似文献
5.
In this work, the Ce3+ doped gadolinium-calcium-silicaborate glass scintillators of the composition ratio 25Gd2O3:10CaO:10SiO2:(55−x)B2O3:xCeF3, have been fabricated by using the melt-quenching technique. The doping concentration of the Ce3+ was varied from 0.05 mol% to 2.5 mol%. The 4f-5d transition of the Ce3+ allowed scintillation with a fast decay time. The absorption spectrum, X-ray induced emission spectrum, photo luminescence spectrum, laser luminescence spectrum and decay time of the scintillators were measured for studying the luminescence properties. From the X-ray induced emission spectrum result, we checked the trend between doping concentration and light yield. The laser induced luminescence spectrum was measured while changing the temperature from 300 K to 10 K. We also measured the decay time by using the laser excitation of the 0.15 mol% Ce3+ doped glass scintillator. 相似文献
6.
D. Wei Y. Huang S. Zhang Y. M. Yu H. J. Seo 《Applied physics. B, Lasers and optics》2012,108(2):447-453
Ce3+ doped ABaPO4 (A=Li, Na, K) phosphors were prepared by conventional high temperature solid-state reaction. The phosphors were investigated by XRD, photoluminescence excitation and emission spectra, and luminescence decay curves. The five 5d levels corresponding to the 4f1→4f05d1 transition of Ce3+ ions were identified. The spectroscopic parameters, e.g., the 5d barycenter, the crystal-field splitting, and the Stokes shift, were discussed. LiBaPO4:Ce3+ phosphor could be efficiently excited by the near-UV lights (330–420 nm) and showed a broad emission band in the range of 430–620 nm with the maximum wavelength at 468 nm. In contrast, Ce3+-doped NaBaPO4 and KBaPO4 showed only excitation bands in a limited UV region (230–370 nm) and have blue emission at 385 nm and 416 nm, respectively. The temperature quenching of luminescence and the chromaticity coordinates were reported. The luminescence properties were discussed by analyzing the crystal structure and the local surroundings of Ce3+ ions on the Ba2+ sites. 相似文献
7.
Luminescence and scintillation properties of newly discovered bromo-elpasolites Cs2NaGdBr6: Ce3+ (CNGB: Ce3+) are presented. Single crystals of CNGB: Ce3+ with dimensions up to Ø7×10 mm3 are successfully grown by the Bridgman technique. X-ray excited luminescence measurements of the grown samples showed a broad emission band in the wavelength range from 365 to 470 nm. It offered an energy resolution of 5.1% (FWHM) at 662 keV for 10% Ce sample. The light output of the investigated samples increases along with cerium concentration. A maximum light yield of ~36,800 ph/MeV is measured for the 10% Ce sample crystal. Under γ-ray excitation, CNGB: Ce3+ crystals showed three exponential decay time components. The scintillation mechanism in the sample crystal is presented. 相似文献
8.
V. Babin V. Gorbenko A. Krasnikov A. Makhov M. Nikl S. Zazubovich Yu. Zorenko 《Radiation measurements》2010,45(3-6):415-418
Luminescence characteristics of Ce3+- and Pr3+-doped aluminium perovskite (LuAlO3, YAlO3) and garnet (Lu3Al5O12, Y3Al5O12) single crystalline films, prepared by the liquid phase epitaxy method with the use of the PbO-based flux, were investigated by the time-resolved spectroscopy methods in the 80–300 K temperature range. The influence of various lead-related centers on the characteristics of the Ce3+- and Pr3+-related luminescence centers was studied. It was found that the presence of lead-related centers in the single crystalline films results in a decrease of the quantum efficiency and appearance of undesirable slow components in the luminescence decay kinetics. The possibilities of improving the scintillation characteristics of the single crystalline films were considered. 相似文献
9.
In this communication, we investigated the scintillation properties of Cs2LiGdCl6:10% Ce3+ single crystal. This scintillation crystal is grown by using the vertical Bridgman technique. X-rays induced emission spectra show that, Cs2LiGdCl6:10% Ce3+ emits into the Ce3+ band, spanning from 365 nm to 450 nm wavelengths. Under γ-ray excitation, the sample crystal shows three main decay time components of 129 ns (51%), 573 ns (32%) and 8.9 μs (17%). It offers an energy resolution of 5.0% (FWHM) for the 662 keV full absorption peak at room temperature. We measured an absolute light yield of 20,000 photons/MeV of absorbed γ-ray energy. We found that with a little exposure to the air, the scintillation properties of the Cs2LiGdCl6:10% Ce3+ crystal deteriorate, which is attributed to the highly hygroscopic nature of this material. We believe that the Cs2LiGdCl6:10% Ce3+ crystal can be a promising material for medical imaging and radiation detection. Moreover due to the presence of Li and Gd constituents, this scintillation crystal can also be the possible candidate for thermal neutron detection. 相似文献
10.
Hong Yu Wenwen Zi Shi Lan Shucai Gan Haifeng Zou Xuechun Xu Guangyan Hong 《Optics & Laser Technology》2012,44(7):2306-2311
Sr3MgSi2O8:Ce3+, Tb3+ phosphor samples were prepared using a solid-state reaction technique, and the photoluminescence properties and energy transfer were investigated. Effective energy transfer occurred in Ce3+/Tb3+ co-doped Sr3MgSi2O8 phosphors. Co-doping of Ce3+ was found to enhance the emission intensity of Tb3+ to a certain extent by transferring energy to Tb3+. The Ce3+/Tb3+ energy transfer was thoroughly investigated through its emission/excitation spectra and photoluminescence decay behavior. The color emitted by Sr3MgSi2O8:Ce3+, Tb3+ phosphors varied from blue to green and can be controlled by altering the concentration ratio of Ce3+ to Tb3+. These results indicate that Sr3MgSi2O8:Ce3+, Tb3+ may be useful as a green-emitting phosphor for ultraviolet whitelight-emitting diodes. 相似文献
11.
In this paper results of scintillation properties measurements of pure and Ce3+-doped strontium fluoride crystals are presented. We measure light output, scintillation decay time profile and temperature stability of light output. X-ray excited luminescence outputs corrected for spectral response of monochromator and photomultiplier for pure SrF2 and SrF2-0.3 mol% Ce3+ are approximately 95% and 115% of NaI–Tl emission output, respectively. A photopeak with a 10% full width at half maximum is observed at approximately 84% the light output of a NaI–Tl crystal after correction for spectral response of photomultiplier, when sample 10 × 10 mm of pure SrF2 crystal is excited with 662 keV photons. Corrected light output of SrF2-0.3 mol% Ce3+ under 662 keV photon excitation is found at approximately 64% the light output of the NaI–Tl crystal. 相似文献
12.
In photoluminescence which directly excites the emission center of phosphor material is known to have a correlation between the emission wavelength and the decay time based on quantum mechanics. In scintillation phenomenon, host lattice of the material is first excited by ionizing radiation and then the excitation energy is transferred to emission centers. For the first time, we investigated the correlation between the scintillation decay and the emission wavelength by using pulse X-ray equipped streak camera system which could observe time and wavelength resolved scintillation phenomenon. Investigated materials were Ce3+, Pr3+ and Nd3+ doped oxides and fluorides which all showed 5d-4f transition based emission. As a result, we obtained the relation that τ (scintillation decay time) was proportional to the λ2.15 (emission wavelength). 相似文献
13.
J.L. Sommerdijk J.A.W. van der Does de Bye P.H.J.M. Verberne 《Journal of luminescence》1976,14(2):91-99
Decay measurements have been performed on the Ce3+ luminescence of LaMgAl11O19 : Ce3+ and of CeMgAl11O19 activated with Tb3+. For all samples, the decay was found to be nearly exponential over at least two decades, and the decay time constant was practically the same, being ≈20 ns. From these results and from quantum efficiency data of the Ce3+ luminescence, conclusions are drawn about the various energy transfers and quenching interactions occurring in these compounds. 相似文献
14.
The paper is devoted to investigation of the luminescent properties of Dy3+ and Dy3+-Ce3+ doped single crystalline films (SCF) grown by LPE method from PbO–B2O3 flux. We have found that the YAG:Dy and YAG:Dy,Ce SCFs possess bright cathodoluminescence in the visible range and good scintillation figure of merit. For this reason LPE grown YAG:Dy and YAG:Dy,Ce SCF are proposed for different applications, namely, as cathodoluminescence screens or screens for microimaging. The Dy3+ co-doping can be also proposed for improvement of the scintillation efficiency of the Ce3+ doped garnet compounds in the SCF form due to Dy3+→ Ce3+ energy transfer and removing the trap related centers in the above RT range. 相似文献
15.
By using metal nitrates as starting materials, SrAl2B2O7: Tb3+ and SrAl2B2O7: Ce3+, Tb3+ powder phosphors were prepared by sol-gel method. X-ray diffraction (XRD), photoluminescence excitation and emission, as well as kinetic decays were employed to characterize the resulting samples. The results show that energy transfers from Ce3+ to Tb3+ ions. The emission intensity of Tb3+ ions in SrAl2B2O7 could be greatly intensified when Ce3+ ions are doped into SrAl2B2O7: Tb3+. The decay times of SrAl2B2O7: Tb3+ were prolonged when Ce3+ ions were doped. The doping of Ce3+ ions not only improved the luminescent intensity, but also made the materials gets stable luminescent properties. 相似文献
16.
Jun Lin Yuan Xiao Jun Wang Ding Bang Xiong Cheng Jun Duan Jing Tai Zhao Yi Bing Fu Chao Shu Shi 《Journal of luminescence》2007,126(1):130-134
Spectroscopic properties of Ce3+ and Pr3+-doped AREP2O7-type alkali rare earth diphosphates (A=Na, K, Rb, Cs; RE=Y, Lu) have been investigated using VUV spectroscopy technique. Ce3+-doped samples show typical Ce3+ emission in the range of 325-450 nm. The strong host absorption band starting at around 160 nm indicates that the optical band gap of AREP2O7 hosts is at least 7.7 eV, and the host→Ce3+ energy transfer process is rather efficient. However, AREP2O7:Pr3+ samples show less efficient host→Pr3+ energy transfer. The direct Pr3+ 4f2→4f15d1 excitation, which are 12160±640 cm−1 higher respect to that of Ce3+, leads to strong 4f15d1→4f2 emission bands in the range of 230-325 nm but no obvious 4f2→4f2 emission lines. 相似文献
17.
The conditions and the mechanisms of crystallization by liquid-phase epitaxy of undoped and Ce3+-doped RAlO3 (R = Lu, Lu-Y, Y, Tb) single-crystalline films on YAlO3 single-crystalline substrates at a considerable mismatch between the lattice constants of the single-crystalline films and
the substrate are analyzed. The maximum values of this mismatch at which the stable growth of the single-crystalline films
is observed are determined. It is demonstrated that transition layers are present between the substrates and the grown single-crystalline
films in which the difference between the lattice parameters of the single-crystalline film and the substrate is diminished.
The optical and luminescence characteristics of the undoped and Ce3+-doped RAlO3 (R = Y, Y-Lu, Lu, Tb) single-crystalline films, as well as the scintillation characteristics of the (Lu-Y)AlO3: Ce single-crystalline films under excitation by alpha-particles of the 239Pu source (5.15 MeV), are investigated. 相似文献
18.
Yu. V. Zorenko V. P. Savchin V. I. Gorbenko T. I. Voznyak T. E. Zorenko V. M. Puzikov A. Ya. Dan’ko S. V. Nizhankovskii 《Physics of the Solid State》2011,53(8):1620-1625
Luminescence and scintillation properties of Y3Al5O12:Ce single crystals grown from the melt by the Czochralski and horizontal directed crystallization methods in various gas
media and Y3Al5O12:Ce single-crystal films grown by liquid-phase epitaxy from a melt solution based on a PbO-B2O3 flux have been comparatively analyzed. The strong dependence of scintillation properties of Y3Al5O12:Ce single crystals on their growth conditions and concentrations of YAl antisite defects and vacancy defects has been established. Vacancy defects are involved in Ce3+ ion emission excitation as the centers of intrinsic UV luminescence and trapping centers. It has been shown that Y3Al5O12:Ce single-crystal films are characterized by faster scintillation decay kinetics than single crystals and a lower content
of slow components in Ce3+ ion luminescence decay during high-energy excitation due to the absence of YAl antisite defects in them and low concentration of vacancy defects. At the same time, the light yield of Y3Al5O12:Ce single-crystal films is comparable to that of single crystals grown by directed crystallization due to the quenching effect
of the Pb2+ ion impurity as a flux component and is slightly lower (∼25%) than the light yield of single crystals grown by the Czochralski
method. 相似文献
19.
A. S. Nizamutdinov L. A. Nurtdinova V. V. Semashko S. L. Korableva 《Optics and Spectroscopy》2014,116(5):732-738
Differential gain spectra in the range 295–335 nm were measured in crystals of scheelite structure LiY1 ? x Lu x F4 (x = 0–1), doped by Ce3+ ions. It is shown that variation of Lu3+ and Y3+ ions relative content in LiY1 ? x Lu x F4 crystals allows to manipulate the spectral width of the amplification band. Cross-sections of excited-state absorption at the wavelengths of Ce3+ luminescence, probability ratios of formation and thermal destruction of color centers depending on the Y3+ ions content in LiY1 ? x Lu x F4 crystals were estimated. Even better gain characteristics have been demonstrated by LiLuF4:Ce3+, doped by Yb3+ ions. The highest optical gain coefficient with a wide amplification band among studied samples was observed in LiLuF4:Ce3+ crystal, codoped by Yb3+ ions. 相似文献
20.
A. Yu. Grippa Yu.N. Datsko O.V. Zelenskaya N.N. Kosinov 《Radiation measurements》2010,45(3-6):398-399
Single crystals of GdCl3 doped with different concentrations of Ce3+ have been grown using the Bridgman–Stockbarger technique and their luminescence and scintillation properties were investigated. The luminescence spectrum of GdCl3:Ce3+ is complex and consists of two bands with maxima at 350 nm and 370 nm. The maximal light yield in GdCl3:Ce3+ was observed at ~1 mol% of Ce3+ (more than 38 000 ph/MeV). 相似文献