Ren Guo-Hao

Growth and properties of Gd:NBW crystal

Gd:NBW crystals are grown by modified Bridgman method for the first time. The Gd segregation coefficient is calculated. Photoluminescence and the light yield of the Gd:NBW crystal are measured. The main elements and the impure ions in the NBW crystal are respectively analyzed by EPMA and GDMS. All these results show that the Gd:NBW crystal is a promising scintillator material.

Temperature dependence of the luminescence properties of LaCl3:Ce crystal

The optical properties of LaCl3:Ce crystal are reported in this paper. Optical transmission spectrum, photoluminescence and time resolved photoluminescence spectra at different temperatures are investigated. It is found that optical transmittance is as high as 80% between 320 nm and 600 nm, and no obvious absorption band is found in this region. Emission intensity and decay time of photoluminescence are quite stable with the change of the temperature between 80 K and 500 K. No thermal quenching is present up to 500 K, and decay time keeps at 17±2 ns. With the increase of the temperature, the whole emission bands and excitation bands present broadening and overlapping, leading to the strengthening of re-absorption of the Ce3+ emission, which makes the emission spectra have a red shift trend.

Growth and Scintillation Properties of GdI

通过坩埚下降法生长GdI3:2%Ce及无掺杂GdI 3 闪烁晶体, 得到?15 mm×20 mm的晶体毛坯, 从中加工出尺寸分别为12 mm×10 mm×2.5 mm和11 mm×8 mm×2.5 mm的无包裹体、无开裂的晶体样品, 封装后检测该晶体光学性能。XRD分析结果表明: 掺杂晶体GdI 3 :2%Ce与无掺杂GdI 3 晶体结构相同。X射线激发发射(XEL)和紫外激发发射谱(PL)测试结果显示: GdI 3 :2%Ce晶体在450~700 nm有宽带发光峰, 发光峰位分别位于520 nm和550 nm, 对应于Ce 3+ 的5d-4f跃迁发光。以550 nm为监控波长, 测得在紫外激发下存在三个激发峰, 分别位于262、335和440 nm。GdI 3 :2%Ce晶体在137Cs源伽马射线(662 keV) 激发下能量分辨率为3.4%, 通过高斯拟合得到的衰减时间为58±3 ns。研究表明, GdI 3 :2%Ce晶体是一种良好的伽马和中子探测材料, 具有广泛的应用前景。通过坩埚下降法生长GdI3:2%Ce及无掺杂GdI 3 闪烁晶体, 得到?15 mm×20 mm的晶体毛坯, 从中加工出尺寸分别为12 mm×10 mm×2.5 mm和11 mm×8 mm×2.5 mm的无包裹体、无开裂的晶体样品, 封装后检测该晶体光学性能。XRD分析结果表明: 掺杂晶体GdI 3 :2%Ce与无掺杂GdI 3 晶体结构相同。X射线激发发射(XEL)和紫外激发发射谱(PL)测试结果显示: GdI 3 :2%Ce晶体在450~700 nm有宽带发光峰, 发光峰位分别位于520 nm和550 nm, 对应于Ce 3+ 的5d-4f跃迁发光。以550 nm为监控波长, 测得在紫外激发下存在三个激发峰, 分别位于262、335和440 nm。GdI 3 :2%Ce晶体在137Cs源伽马射线(662 keV) 激发下能量分辨率为3.4%, 通过高斯拟合得到的衰减时间为58±3 ns。研究表明, GdI 3 :2%Ce晶体是一种良好的伽马和中子探测材料, 具有广泛的应用前景。

lt;inf

纯碘化铯晶体是一种具有快衰减闪烁特性的新型辐射探测材料, 在伽马射线、中子和其它辐射探测技术中有重要的应用前景。本研究以Bridgman法所生长的纯碘化铯为对象, 分别研究了该晶体的透射光谱以及在紫外光、连续X射线、脉冲X射线和宇宙射线激发下的发射光谱、时间响应特性和沿晶体生长方向不同部位的光输出分布特点。实验测得晶体的吸收边为240 nm, 激发和发射波长分别位于241 nm和318 nm, 发光衰减时间分别为2~3 ns和18~25 ns。以尺寸为30 mm×30 mm×200 mm的晶体籽晶端和尾端与PMT耦合所测得的光输出分别是143 p.e/MeV和127 p.e./MeV, 尽管晶体两端的光输出存在12.6%的差异, 但没有观察到衰减时间长于100 ns的慢分量。这些性能进一步证明纯碘化铯晶体具有作为快闪烁体的优势。纯碘化铯晶体是一种具有快衰减闪烁特性的新型辐射探测材料, 在伽马射线、中子和其它辐射探测技术中有重要的应用前景。本研究以Bridgman法所生长的纯碘化铯为对象, 分别研究了该晶体的透射光谱以及在紫外光、连续X射线、脉冲X射线和宇宙射线激发下的发射光谱、时间响应特性和沿晶体生长方向不同部位的光输出分布特点。实验测得晶体的吸收边为240 nm, 激发和发射波长分别位于241 nm和318 nm, 发光衰减时间分别为2~3 ns和18~25 ns。以尺寸为30 mm×30 mm×200 mm的晶体籽晶端和尾端与PMT耦合所测得的光输出分别是143 p.e/MeV和127 p.e./MeV, 尽管晶体两端的光输出存在12.6%的差异, 但没有观察到衰减时间长于100 ns的慢分量。这些性能进一步证明纯碘化铯晶体具有作为快闪烁体的优势。

gt;3

用坩埚下降法生长得到Cs 2 LiY 0.95 Cl 6 : 5%Ce(CYLC)闪烁晶体, 通过X射线衍射分析证明Cs 2 LiYCl 6 :Ce的晶体结构属于钾冰晶石结构, 并与理论计算结果基本吻合。在吸收光谱中观测到源于Ce 3+ 离子从4f向5d1~5电子跃迁的吸收峰和自陷激子吸收峰。X射线和紫外激发和发射光谱测试表明, 位于300 nm的发光属于Cs 2 LiYCl 6 :Ce晶体的本征芯价发光, 321 nm的发光归因于自陷激子发光, 350~450 nm范围的发光属于Ce 3+ 离子5d-4f 跃迁发光。在37Cs源伽马射线激发下, CYLC晶体的能量分辨率达到8.1%, 衰减时间分别为58 ns和580 ns。综上所述可知, Cs 2 LiYCl 6 :Ce晶体将是一种在中子和伽马射线分辨领域具有广泛应用前景的闪烁晶体。Crystal structure of Cs2LiY0.95Cl6:5%Ce crystal (CYLC): grown by vertical Bridgement method from polycrystal raw materials was measured by X-ray diffraction (XRD) and was proved to have elpasolite structure. The detected structure of Cs2LiYCl6:Ce crystal was agreed well with theoretical structure. Six optical absorption bands which are suggested to originate from the transition of electron from 4f to 5d(1 similar to 5) of Ce ions and self-trapped excition (STE), can be identified in the absorption spectra of the CLYC:Ce crystal. X-ray and ultraviolet excited luminescence spectra of Cs2LiY0.95Cl6:5%Ce crystal present an emission band from 350 nm to 450 nm corresponding to 5d-4f transitions of Ce3+ ions. The peaks locating at 300 nm and 321 nm can be ascribed to core to valence luminescence and STE luminescence. Under the excitation of gamma-rays from Cs-137, Cs2LiY0.95Cl6:5%Ce crystal presents energy resolution of 8.1%, and scintillation decay time of 58 ns and 580 ns. All of these properties show that Cs2LiYCl6:Ce crystal is a promising scintillator for neutron and gamma detection applications.

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Lu0.1Y0.9AlO3:Ce single crystals in dimensions ?30?90?mm3 are successfully grown by the Czochralski method. The light output and energy resolution of the crystal in dimensions ?14?2?mm3 are 9420 photons/MeV and 12.5% respectively. Dependence of the light output on the thickness of the sample is found and explained by the self-absorption in the range of 320?370?nm and the underlying parasitic absorption around 250?nm. In addition, the local enrichment of Ce ions and the presence of low-valent impurity ions may cause the deterioration of its light output. In addition, Lu0.1Y0.9AlO3:Ce has an almost constant fluorescence decay time of 16?ns in the temperature range of 80?373?K.

gt;:Ce Crystal

The transmission spectra of cubic β-PbF2 crystals grown by the non-vacuum Bridgman method were measured with a spectrophotometer. It was found that there are several optical absorption bands peaking at 300 nm, 390-400 nm, as well as at 460 nm. According to composition analysis, doping and annealing experiments, it is suggested that the absorption at 300 nm originates from the electron transition of Ce ions from 4f→5d. The absorption at 390-400 nm may result from the colour centres related to oxygen impurities. In addition, the sample recrystallized from the coloured β-PbF2 crystal exhibits a new absorption band at 460 nm, which might be caused by trace lead vacancies.

Luminescence and Decay Time Properties of Pure CsI Crystals

通过坩埚下降法生长GdI3:2%Ce及无掺杂GdI 3 闪烁晶体, 得到?15 mm×20 mm的晶体毛坯, 从中加工出尺寸分别为12 mm×10 mm×2.5 mm和11 mm×8 mm×2.5 mm的无包裹体、无开裂的晶体样品, 封装后检测该晶体光学性能。XRD分析结果表明: 掺杂晶体GdI 3 :2%Ce与无掺杂GdI 3 晶体结构相同。X射线激发发射(XEL)和紫外激发发射谱(PL)测试结果显示: GdI 3 :2%Ce晶体在450~700 nm有宽带发光峰, 发光峰位分别位于520 nm和550 nm, 对应于Ce 3+ 的5d-4f跃迁发光。以550 nm为监控波长, 测得在紫外激发下存在三个激发峰, 分别位于262、335和440 nm。GdI 3 :2%Ce晶体在137Cs源伽马射线(662 keV) 激发下能量分辨率为3.4%, 通过高斯拟合得到的衰减时间为58±3 ns。研究表明, GdI 3 :2%Ce晶体是一种良好的伽马和中子探测材料, 具有广泛的应用前景。通过坩埚下降法生长GdI3:2%Ce及无掺杂GdI 3 闪烁晶体, 得到?15 mm×20 mm的晶体毛坯, 从中加工出尺寸分别为12 mm×10 mm×2.5 mm和11 mm×8 mm×2.5 mm的无包裹体、无开裂的晶体样品, 封装后检测该晶体光学性能。XRD分析结果表明: 掺杂晶体GdI 3 :2%Ce与无掺杂GdI 3 晶体结构相同。X射线激发发射(XEL)和紫外激发发射谱(PL)测试结果显示: GdI 3 :2%Ce晶体在450~700 nm有宽带发光峰, 发光峰位分别位于520 nm和550 nm, 对应于Ce 3+ 的5d-4f跃迁发光。以550 nm为监控波长, 测得在紫外激发下存在三个激发峰, 分别位于262、335和440 nm。GdI 3 :2%Ce晶体在137Cs源伽马射线(662 keV) 激发下能量分辨率为3.4%, 通过高斯拟合得到的衰减时间为58±3 ns。研究表明, GdI 3 :2%Ce晶体是一种良好的伽马和中子探测材料, 具有广泛的应用前景。

Optical and Scintillation Properties of Cs

纯碘化铯晶体是一种具有快衰减闪烁特性的新型辐射探测材料, 在伽马射线、中子和其它辐射探测技术中有重要的应用前景。本研究以Bridgman法所生长的纯碘化铯为对象, 分别研究了该晶体的透射光谱以及在紫外光、连续X射线、脉冲X射线和宇宙射线激发下的发射光谱、时间响应特性和沿晶体生长方向不同部位的光输出分布特点。实验测得晶体的吸收边为240 nm, 激发和发射波长分别位于241 nm和318 nm, 发光衰减时间分别为2~3 ns和18~25 ns。以尺寸为30 mm×30 mm×200 mm的晶体籽晶端和尾端与PMT耦合所测得的光输出分别是143 p.e/MeV和127 p.e./MeV, 尽管晶体两端的光输出存在12.6%的差异, 但没有观察到衰减时间长于100 ns的慢分量。这些性能进一步证明纯碘化铯晶体具有作为快闪烁体的优势。纯碘化铯晶体是一种具有快衰减闪烁特性的新型辐射探测材料, 在伽马射线、中子和其它辐射探测技术中有重要的应用前景。本研究以Bridgman法所生长的纯碘化铯为对象, 分别研究了该晶体的透射光谱以及在紫外光、连续X射线、脉冲X射线和宇宙射线激发下的发射光谱、时间响应特性和沿晶体生长方向不同部位的光输出分布特点。实验测得晶体的吸收边为240 nm, 激发和发射波长分别位于241 nm和318 nm, 发光衰减时间分别为2~3 ns和18~25 ns。以尺寸为30 mm×30 mm×200 mm的晶体籽晶端和尾端与PMT耦合所测得的光输出分别是143 p.e/MeV和127 p.e./MeV, 尽管晶体两端的光输出存在12.6%的差异, 但没有观察到衰减时间长于100 ns的慢分量。这些性能进一步证明纯碘化铯晶体具有作为快闪烁体的优势。

lt;inf

用坩埚下降法生长得到Cs 2 LiY 0.95 Cl 6 : 5%Ce(CYLC)闪烁晶体, 通过X射线衍射分析证明Cs 2 LiYCl 6 :Ce的晶体结构属于钾冰晶石结构, 并与理论计算结果基本吻合。在吸收光谱中观测到源于Ce 3+ 离子从4f向5d1~5电子跃迁的吸收峰和自陷激子吸收峰。X射线和紫外激发和发射光谱测试表明, 位于300 nm的发光属于Cs 2 LiYCl 6 :Ce晶体的本征芯价发光, 321 nm的发光归因于自陷激子发光, 350~450 nm范围的发光属于Ce 3+ 离子5d-4f 跃迁发光。在37Cs源伽马射线激发下, CYLC晶体的能量分辨率达到8.1%, 衰减时间分别为58 ns和580 ns。综上所述可知, Cs 2 LiYCl 6 :Ce晶体将是一种在中子和伽马射线分辨领域具有广泛应用前景的闪烁晶体。Crystal structure of Cs2LiY0.95Cl6:5%Ce crystal (CYLC): grown by vertical Bridgement method from polycrystal raw materials was measured by X-ray diffraction (XRD) and was proved to have elpasolite structure. The detected structure of Cs2LiYCl6:Ce crystal was agreed well with theoretical structure. Six optical absorption bands which are suggested to originate from the transition of electron from 4f to 5d(1 similar to 5) of Ce ions and self-trapped excition (STE), can be identified in the absorption spectra of the CLYC:Ce crystal. X-ray and ultraviolet excited luminescence spectra of Cs2LiY0.95Cl6:5%Ce crystal present an emission band from 350 nm to 450 nm corresponding to 5d-4f transitions of Ce3+ ions. The peaks locating at 300 nm and 321 nm can be ascribed to core to valence luminescence and STE luminescence. Under the excitation of gamma-rays from Cs-137, Cs2LiY0.95Cl6:5%Ce crystal presents energy resolution of 8.1%, and scintillation decay time of 58 ns and 580 ns. All of these properties show that Cs2LiYCl6:Ce crystal is a promising scintillator for neutron and gamma detection applications.