掺杂钨酸铅晶体闪烁发光光谱研究  

Study of Scintillating Luminescence Spectra of Lead Tungstate Scintillation Crystal Doped with Ions

作　　者：万尤宝[1,2] 吴宇容[2] 张建新[2] 杨培志[3] 肖林荣[2] 杨辉[1] 

机构地区：[1]浙江大学材料与化工学院无机材料研究所,浙江杭州300200 [2]嘉兴学院先进材料研究所,浙江嘉兴314001 [3]云南师范大学可再生能源先进技术与制备教育部重点实验室,云南昆明650092

出　　处：《光谱学与光谱分析》2009年第9期2313-2316,共4页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(69578025);浙江省国际合作重大攻关项目(2006C14029);浙江省自然科学基金项目(Y105459)资助

摘　　要：利用改进的晶体生长设备和工艺提高了PbWO4闪烁晶体的光产额。通过对生长获得的PbW04、退火PbWO4和BaR：PbWO4晶体的透过光谱，衰减时间和光产额等闪烁性质的研究，发现晶体退火和掺杂技术特别是阴离子掺杂技术能够显著提高晶体的闪烁发光性能。其中晶体掺杂全面提高了晶体的透过光谱强度，但是退火的影响较复杂。高温退火改善了PbWO4晶体在360nm以上波段的透过光谱的透过率，但是在320~360nm波段其透过率反而降低。这些现象与晶体中缺陷在可见光波段产生的特征吸收有关。晶体的良好退火和掺杂提高了晶体的光产额，其中BaFz：PbWO4掺杂晶体室温闪烁发光强度达到65p．e．·（MeV）-1，接近PET的使用要求。这种提高与晶体F离子掺杂引发晶体[WU4]2-四面体基团畸变有关，F-离子进入该四面体产生了新的发光中心。The light yield of the as-grown PbWO4, annealed PbWO4 and BaF2 ： PbWO4 crystals were raised by utilizing our improved crystal growth instrument and technique. Their scintillating properties including transmittance, decay time and light yield were studied. Results reveal that the scintillating performances of the crystals were improved evidently by using the crystal an- nealing technique and the ions doping technique, especially the negative ions doping technique. The influence results of the two techniques are different. The ions doping technique raises their transmittance intensity in the whole measuring wavelength range. But the influence of annealing PbWO4 crystal on their transmittance is complicated. It improves its transmittance intensity at the wavelength above 360 nm, but weakens the transmittance intensity of the annealed PbWO4 crystal in the wavelength range from 320 to 360 nm. These phenomena should be related to the crystal defects which have absorption peaks in this wavelength range, especially for VPb3＋ defect which has characterized absorption peaks in this wavelength range. Also, the absorption of the defects influences the character of the decay time of these crystals. The big defect concentration relates to the short decay time. It should be mentioned that the ions doping technique reduces the defect content in the crystal, which is beneficial to the high transmit- tance intensity but induces slightly longer decay time than that of as-grown crystal and well annealed PbWO4 crystal. Also, the ions doping technique of the F- ion doped crystal leads to high light yield. The annealing technique and ions doping technique improve the light yield of crystals. The light yield of BaF2 ： PbWO4 reaches 65 p. e./MeV, which is near to the requirement of PET. The good result is related to the degeneration of the [WO4]2- tetrahedron induced by the F- occupying the O2 site in the crystal cell.

关 键 词：闪烁晶体 温度梯度法 透过光谱 衰减时间 光产额 

分 类 号：TN213.2[电子电信—物理电子学] O423[理学—声学]