共查询到18条相似文献,搜索用时 474 毫秒
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掺铈硅酸镥(Lu2SiO5:Ce)晶体的生长与闪烁性能 总被引:2,自引:0,他引:2
用Czochralsky方法和铱坩埚感应加热技术生长出了尺寸为φ35mm×40mm的掺铈硅酸镥(LSO:Ce)闪烁晶体.透射光谱表明,由于铈离子的掺入,使晶体的吸收边由纯LSO晶体的195nm红移至380nm.LSO:Ce晶体的紫外激发波长按强度递减的顺序依次为380、333、319和216nm,其光发射为带状谱,波长覆盖范围从390nm至560nm.X射线激发的发射谱具有典型的双峰特征,峰值波长为393nm和.426nm.这些特征与Ce3+离子基态能级4f1因自旋-轨道耦合而产生的两个分裂能级和Ce+离子在LSO晶体中占据两个不同的结晶学格位有关. 相似文献
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采用提拉法和铂坩埚感应加热技术生长出最大尺寸为直径25mm,长40mm的Li6Gd(BO3)3:Ce晶体,XRD分析表明,生长出的晶体为单一的Li6Gd(BO3)3:Ce相,结构属P21/c空间群.对晶体生长中存在的解理开裂、应力开裂及多晶问题进行了讨论,并从晶体结构的角度解释了(020)完全解理面出现的原因.晶体在380-800nm之间的透过率接近90%,200-380nm之间的吸收是由Ce^3+离子的4f-5d跃迁和Gd^3+离子的4f-4f跃迁引起的.不同激发源激发下的发射均显示Ce^3+离子的双谱峰特征;相比于紫外激发下的发射而言,X射线激发下的发射光谱略有红移.该晶体发光符合单指数衰减模型,衰减时间为30.74ns,在241^Am源的α射线激发下晶体的能量分辨率为28.84%. 相似文献
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采用中频感应提拉法生长出尺寸为φ60mm×110mm的CeLu1.6Yo.4SiO5(LYSO)晶体,与LSO晶体相比,LYSO晶体的优势是提高了晶体质量、降低了熔点和原料成本等.在室温下测试了LYSO晶体的透过光谱、激发光谱和发射光谱,结果表明Y的加入使LSO晶体的吸收边向短波方向偏移.Ce3+的4f1→5d1跃迁吸收导致紫外区产生三个吸收带.发射光谱具有Ce3+典型的双峰特征,经Gaussian多峰值拟合,双峰395nm和418nm归属于Ce1发光中心,而435nm的发光峰与Ce2发光中心有关. 相似文献
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采用提拉法制备了LuxY1-xAlOa:Ce晶体样品,通过XRD物相分析和成分分析,并结合Lu2O3-Al2O3二元体系相图以及LuxY1-xAlO3:Ce 结构稳定性方面的分析与讨论,结果表明:随着熔体中Lu元素含量的增加,熔体分层加剧,析晶LuxY1-xAlO3:Ce相的熔体组成区间将向富Lu一侧偏移,这使得晶体上部易伴生(Lu,Y)3Al5O12:Ce相;而随着Lu元素含量的提高, LuxY1-xAlO3:Ce晶体的热稳定性降低,氧空位的存在则使晶体的热稳定性进一步降低,在接种过程中籽晶表面易发生相分解反应生成(Lu,Y)3Al5O12:Ce和(Lu,Y)4Al2O9:Ce,籽晶表面相分解产物(Lu,Y)3Al5O12:Ce提供了诱导析晶(Lu,Y)3Al5O12:Ce相所需的晶核,这使得晶体的外表面处易伴生(Lu,Y)3Al5O12:Ce相.调整配料组成使n((Lu,Y)2O3):n(A12O3)=1.17~100,加大熔体内部和固液界面处的温度梯度以改善熔体对流、抑制熔体分层以及籽晶表面处的相分解等有助于高Lu元素含量LuxY1-xAlO3:Ce晶体的获得. 相似文献
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Thin plates of Bi12SiO20 (BSO) single crystal were grown by the EFG method. In this experiment, three different kinds of dies with planar, angular-concave, and concave top geometries were used. The experiment proved that it is possible to achieve stable growth of cm-sized thin plates of BSO single crystals using a die with a concave die-top geometry. The effect of die-top geometry on growth stability is qualitatively explained according to the meniscuc model developed by V. A. Tatarchenko. 相似文献
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Hayet Farhi Kheirreddine Lebbou Soliman Belkahla Laurent Grosvalet Benoit Hautefeuille Armen Caramanian Christophe Dujardin Olivier Tillement Christain Pedrini 《Optical Materials》2008,30(9):1461-1467
The laser heated pedestal growth (LHPG) technique has been applied to grow undoped and doped Lu2SiO5:Ce3+ (LSO:Ce) single crystals fibers with stable diameter. The starting cerium concentration in the melt was [0.05–1] at.%. The thermal and growth conditions allowing pulling transparent single crystals fiber’s were optimised. The fibers have been grown under N2 + 1% O2 atmosphere (1 bar). The Ce3+ segregation coefficient is 0.28 greater than the crystal grown by Czochralski technique. The as grown fibers demonstrated scintillating properties. 相似文献
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Y. F. Zhou J. Y. Xu Y. Liu L. D. Chen Y. Y. Huang W. X. Huang 《Bulletin of Materials Science》2007,30(3):211-214
Space grown BSO crystal doped with Ce was characterized by means of X-ray fluorescence spectra, X-ray topography, dislocation
density etc. Influence of microgravity on Ce-doped BSO crystal defect was studied by comparing space grown BSO crystal with
ground grown one. These results show that compositional homogeneity and structural perfection of crystal can be improved under
microgravity conditions. 相似文献
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在BSO晶体中同时掺入Ce和Eu离子,生长了Ce:Eu:BSO晶体,对晶体的二波耦合和四波混频性能了测试。结果表明,Ce和Eu离子对晶体的光折变效应起到了增强的作用。 相似文献
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Y. F. Zhou Z. L. Pan Y. Liu F. Ai N. F. Chen Y. Y. Huang W. He L. A. Tang J. C. Wang 《Microgravity science and technology》2005,17(1):3-7
Ce doped Bi12SiO20 single crystals were grown either on board of the Chinese Spacecraft-Shenzhou No.3 (SZ-3) or on the ground at the same conditions
with the exception of microgravity. The surface morphology of crystals clearly showed significant differences between the
space- and ground-grown portions. The space- and ground-grown crystals have been measured by X-ray rocking curve, Ce concentration
distribution in growth direction, dislocation density, absorption spectrums. These results show that the compositional homogeneity
and structural perfection of Ce doped crystal grown in space are obviously improved. 相似文献
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T.I. Milenov P.M. RafailovC. Thomsen A. EgoryshevaR. Titorenkova B. KostovaV. Skorikov 《Optical Materials》2011,33(11):1573-1577
Crystals of BSO doped with Se in two different concentrations (BSO:Se(I) and BSO:Se(II)) were grown by the Czochralski method. It is established that doping with Se is accompanied with preferential absorption of Fe from the melt. According to the in-depth chemical analysis, it is assumed that the doping Se ions enter the tetrahedral positions by means of the substitution of 3Si4+ by (Se6+ + 2Fe3+) ions. The measured absorption spectrum of the low-concentration Se-doped crystal (BSO:Se(I)) confirms such a conclusion as the absorption coefficient is increased in a broad spectral interval (1.4-3.1 eV) - an effect typical for all Fe-doped Bi12SiO20 crystals. The polarized Raman spectra of BSO:SeI show that the doping-induced lattice distortions are small. The IR spectrum of the BSO:SeI crystal yields indications for local lowering of the symmetry of the Fe-occupied tetrahedral positions. Doping with Se at high concentration (BSO:Se(II)) leads to occasional second phase inclusions and to a downshift of practically all modes in the Raman spectrum by 2-5.5 cm−1. It is concluded that the doping with Se at high concentrations follows the same mechanism as that at low concentrations but the introduced lattice distortions are more significant, and lead to an enlargement of the unit cell while preserving the overall cubic symmetry. 相似文献