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XU Yan-Ling WANG Rui WANG Bin-Ju LIU Wei-Hai WANG Jia WANG Miao YANG Tong-Yong 《中国物理快报》2008,25(6):2246-2248
Zn and RE (RE=La, Yb, Y) ions co-doped PbWO4 (PWO) single crystal grown by the Czochralski technique are characterized by x-ray diffraction (XRD), opticaltransmission spectra, and photoluminescence (PL). The doping of Zn ions shows distinct effects on the properties of PWO:RE crystals. At low concentration of Zn ions (200ppm), the luminescence intensity is quite weak for (Zn,La)-doped PWO, but is substantially strong for (Zn,Yb)-doped PWO. The blue luminescence intensity is significantly enhanced with the increasing Zn ions doping for PWO:Y. The trivalent ions codoping can increase the ratio of the blue luminescence contributing to the fast components of light yield. Ybions can enhance efficiency of luminescence in PWO:Yb:Zn because they may act as a luminous sensitization agent which can be involved in the efficient energy transfer and storage of the radiative process. 相似文献
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钨酸铅(PWO)晶体是一种综合性能非常优异的无机闪烁晶体,并且在高能物理研究领域已获得重要应用,但光输出偏低的缺点严重制约了它在非高能物理领域的应用.本文采用氟化铅作为掺杂剂,用Bridgman方法生长出了光输出比普通PWO晶体高出2—3倍的新型PWO晶体.紫外和X射线荧光光谱的测试结果表明,这种新型晶体的发光波长比纯PWO晶体红移了大约134 nm,即为553 nm,衰减时间也从几十纳秒延长到100 ns以上,且光输出随积分时间的增加而增强.此外,发射波长和光输出沿晶体生长方向存在明显的位置依赖性,初期 相似文献
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通过透射光谱、光产额(LY)和光致发光等发光性能测试,研究了F,Y双掺钨酸铅(PbWO4 ,简称PWO)晶体的发光性能,并利用热释光曲线和正电子湮没寿命谱对F,Y双掺PWO晶 体中的缺陷种类和变化进行了分析. 结果表明:与未掺杂晶体相比,双掺样品在350nm附近 的透过率大大提高,吸收边向短波方向移动约30nm,光致发光谱中出现位于350nm的发光峰 ,双掺样品的LY(100ns内)为未掺杂PWO的2.7倍左右.晶体中主要存在的缺陷为(WO3)-
关键词:
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Y双掺钨酸铅闪烁晶体
高光产额
热释光
正电子湮没寿命谱 相似文献
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通过透射光谱、x射线激发发射光谱(XSL)的测试,研究了Bridgman法生长的几种不同+3价离子掺杂钨酸铅晶体的发光性能,并利用正电子湮没寿命谱(PAT)和x光电子能谱(XPS)的实验手段,对不同钨酸铅晶体的微观缺陷进行研究.实验表明,不同的+3价离子掺杂,对钨酸铅晶体发光性能的改善不同,并使得晶体中正电子俘获中心和低价氧的浓度发生不同变化.其中掺镧晶体的正电子俘获中心和低价氧浓度均上升,而掺钇和掺铋晶体的正电子俘获中心和低价氧浓度均下降,掺锑晶体则出现了正电子俘获中心浓度上升、低价氧浓度下降的情况.提
关键词:
钨酸铅晶体
+3价离子掺杂
正电子湮没寿命谱
x光电子能谱 相似文献
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Nb2O5掺杂对提高钨酸铅晶体发光性能的微观研究 总被引:4,自引:2,他引:2
通过透射谱、X射线激发发射谱(XSL)的测试,研究了布里奇曼(Bridgman)法生长的掺铌钨酸铅晶体的发光性能,并利用正电子湮没寿命谱(PAT)和X射线光电子能谱(XPS)的实验手段,对其微观缺陷进行了深入研究。结果表明,铌掺杂能够有效地改善钨酸铅晶体的350nm吸收带,提高钨酸铅晶体的发光快成分比例,并使得晶体中的正电子捕获中心浓度上升,低价氧浓度上升。提出掺铌钨酸铅晶体中Nb^5 将占据W^6 格位并使得晶体内部分(WO4)^2-根团成为(NbO3 Vo)^-,由此可改善钨酸铅的发光性能。 相似文献
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The major components PbO and WO3 in PWO crystals, Bi2O3 and GeO2 in BGO crystals, as well as Gd, La, Nb, Mg, Mo, Bi, Sb and Y doped in PWO crystals and Eu doped in BGO crystals were successfully determined with X‐ray fluorescence spectroscopy (XRF) using fusion techniques. Calibration standards were synthesized with high‐purity oxides and standard solutions. The analysis results can meet the general requirements of the quality control of the crystal growth and research purpose. The relative standard deviations for Bi2O3, GeO2, PbO and WO3 are 0.21%, 0.18%, 0.25% and 0.22%, respectively (k = 8). The detection limits for dopants in PWO are below 5 µg/g for Gd, La, Nb, Mo, Sb and Y and below 20 µg/g for Mg and Bi. The detection limits for Eu doped in BGO are 8 µg/g. The testing results of XRF were compared with those of inductively coupled plasma optical emission spectroscopy. It was found that the relative differences of the testing results between the two methods are less than 10% for most dopants in PWO crystals. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Yu. Zorenko A. Voloshinovskii Z. Moroz M. Pashkovsky I. Konstankevych I. Solsky 《Radiation measurements》2004,38(4-6):397-401
In PbWO4(PWO) crystals grown by Czochralski method the influence of atmosphere of the growth (O2, air) and doping with the rare-earth ions of different types (A3+=Lu3+, Gd3+,Tb3+,Eu3+ as well as doubly doped A3+–Li+) on light yield and luminescence decay were analyzed. PWO scintillator with the ultra-fast (τ=0.5 ns) main component of luminescence decay (87% of total light yield) was obtained using the O2-growth atmosphere and doping by Eu2O3 at a concentration of 5000 ppm. It is concluded that the decrease of decay constant of the main scintillation component is the result of the resonant energy transfer between the centers of “blue” PWO luminescence (λmax=420 nm) and the 4f–4f-transitions of Eu3+ ions in this spectral region. 相似文献
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Lead tungstate PbWO 4 crystals are one of the most effective scintillation materials for calorimetric devices designed to detect elementary particles with extremely high energies [1]. The interest to PbWO 4 scintillation and luminescence properties increased noticeably in the recent years [1, v 2]. However, experimental results obtained for PbWO 4 optical properties, substantially differ for crystals, produced under different growing conditions. Such a variety led to the situation, that up to now there are no generally accepted explanations for the origin of luminescence centres in PbWO 4 . The electronic structure of possible luminescent centres in perfect lead tungstate crystals PbWO 4 and in the crystals with molybdenum impurity PbWO 4 :Mo is ab-initio calculated in order to elucidate the origin of luminescence in lead tungstate crystals. Conclusions concerning excitation of self luminescence in perfect crystals and defect luminescence in Mo-doped crystals are made on the basis of results of calculations and experimental data on luminescence and photo excitation of PbWO 4 and PbWO 4 :Mo crystals. 相似文献
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The electronic structures and absorption spectra of PWO crystals containing interstitial oxygen ions have been calculated using density functional theory code CASTEP with lattice structure optimized. It is shown by calculation that: (1) the interstitial oxygen ion in the perfect PWO crystal doesn’t bring any obvious absorption in the visible region; (2) the green emission of lead tungstate origin is closely related to the interstitial oxygen ion, and probably originates from the center of “ WO4+Oi”. 相似文献
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O. V. Rzhevskaya D. A. Spasskiĭ V. N. Kolobanov V. V. Mikhaĭlin L. L. Nagornaya I. A. Tupitsina B. I. Zadneprovskiĭ 《Optics and Spectroscopy》2008,104(3):366-373
Luminescence properties of a pure CdWO4 crystal and a CdWO4:Mo crystal doped with molybdenum in different concentrations have been investigated. The effect of molybdenum impurity on the intrinsic luminescence of CdWO4 has been found, and the role of the impurity in the formation of new luminescence centers has been investigated. The features of the formation of the intrinsic and impurity luminescence excitation spectra of CdWO4 and CdWO4:Mo crystals in the fundamental-absorption region have been considered. The reflection spectra of the CdWO4 crystal have been investigated taking into account the crystal structure anisotropy. 相似文献
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A.L.N. Stevels 《Journal of luminescence》1978,17(1):121-133
In Al2O3 rich Ba-aluminate: Eu phosphors a green luminescence band involving Eu is found next to the blue Eu2+-luminescence. The green band is ascribed to associates of Eu and oxygen ions at Ba sites. These OBa ions also influence the concentration quenching behaviour of the Ba aluminate with high Eu content. The drop in the quantum efficiency of Ba-aluminate: Eu2+ on decreasing the Eu content of phosphors is not related to the presence of OBa. It is explained by the presence of Ba-vacancies. No green luminescence was observed in Mg-rich β-alumina type Eu2+ phosphors. Also, the quenching of the luminescence at higher Eu concentrations is less. Most probably, Mg2+ ions, positioned in between OBa and Eu2+, block the interaction between last-named ions. 相似文献
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Time-resolved emission and excitation spectra and luminescence decay kinetics were studied at 150-300 K for the green emission of PbWO4:Mo crystals. It was found that the slow (μs-ms) decay component observed under excitation in the defect-related absorption region (around 3.8-3.9 eV) arises from the G(II) emission which appears at the tunneling recombination of optically created electron and hole centers. The study of the emission decay kinetics at different temperatures and excitation intensities allowed concluding that both the monomolecular and the bimolecular tunneling recombination process can be stimulated in the mentioned energy range. The monomolecular process takes place in the isolated spatially correlated pairs of electron and hole centers produced without release of electrons into the conduction band. The bimolecular process takes place in the pairs of randomly distributed centers created at the trapping of free electrons from the conduction band. The formation of electron centers under irradiation in the defect-related absorption region was investigated by the electron spin resonance (ESR) and thermally stimulated luminescence (TSL) methods. The possibility of various photo-thermally stimulated defects creation processes, which take place with and without release of free electrons into the conduction band, was confirmed. 相似文献
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采用固相法制备了LiM(M=Ca, Sr, Ba)BO3 : Dy3+材料,并研究了材料的发光特性。LiM(M=Ca, Sr, Ba)BO3 : Dy3+材料的发射光谱均呈多峰发射,对应于Ca,Sr,Ba,其主发射峰分别是Dy3+的4F9/2→6H15/2(484,486,486 nm),6H13/2(577,578,578 nm)和6H11/2(668,668,666 nm)跃迁。监测黄色发射峰时,所得激发光 谱峰值位置相同,主激发峰分别为331,368, 397,433,462,478 nm,对应Dy3+的6H15/2→ 4D7/2,6P7/2,6M21/2,4G11/2,4I15/2和6F9/2跃迁。研究了敏化剂Ce3+及电荷补偿剂Li+、Na+和K+对LiM(M=Ca, Sr, Ba)BO3 : Dy3+材料发光强度的影响。结果显示:加入敏化剂Ce3+提高了材料的发光强度,发光强度最大处对应的Ce3+浓度为3%;加入电荷补偿剂Li+、Na+和K+后,材料的发光强度也得到了明显提高,但发光强度最大处对应的Li+、Na+和K+浓度不同,依次为4%、4%和3%。 相似文献
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采用固相法制备了绿色LiM(M=Ca,Sr,Ba)BO3:Tb3+发光材料.测量结果显示材料均可被紫外(350~410 nm)光激发,发射绿光.研究了Tb3+浓度对材料发射光谱的影响,结果显示,随Tb3+浓度的增大,发射光谱峰位未发生变化,但其强度呈现出先增大后减小的趋势,即:存在浓度猝灭效应.加入电荷补偿剂Li+,Na+和K+提高了LiM(M=Ca,Sr,Ba)BO3:Tb抖材料的发射强度. 相似文献
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A. Kotlov L. Jnsson M. Kirm A. Lushchik V. Nagirnyi E. Rivkin A. Watterich B. I. Zadneprovski 《Radiation measurements》2004,38(4-6):715-718
Thermostimulated and photostimulated luminescence of ZnWO4, ZnWO4:Fe and ZnWO4:Mo crystals irradiated at low temperatures by X-rays or UV photons was studied in the temperature range 4.2–300 K in order to clarify the creation and recombination processes of the elementary colour centres. The connection of the luminescence phenomena with the self-trapped holes has been revealed. 相似文献
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The influence of reducing annealing and repeated oxidizing annealing of the Li2B4O7:Mn single crystals on their thermostimulated luminescence (TSL) and X-ray luminescence (XL) has been studied. Because of the oxygen vacancies formation and the dopant ions reduction, the reducing annealing results in a drastic decrease of the luminescence intensity along with the simultaneous shift of a part of the maxima and redistribution of the peak intensities. The repeated annealing in the oxidizing environment leads only to the partial reduction of the luminescent properties of the Li2B4O7:Mn crystals. 相似文献