(Lu,Y)2SiO5∶Ce3+与SrSO4∶Dy3+材料低温热释光及其测试仪器的研究

为了分析材料在低温下的陷阱能级, 获得更多有关缺陷结构的信息, 研制了一套由STM32微控制器为核心的低温热释光发光谱测量系统。设计了低温样品室,采用液氮冷却样品; STM32通过控制加热电流, 实现样品以恒定速率升温, 从而获得低温热释光发光曲线或三维热释光谱。温度测量范围为85~400 K, 升温速率范围为0.1~10 K/s。设计了由STM32控制X射线及紫外光源的驱动电路, 用于样品的激发。采用高灵敏度CCD实现对三维热释光谱的测量, 采用单光子计数器获取二维热释光发光曲线。利用该系统测试了(Lu,Y)2SiO5∶Ce3+(LYSO∶Ce3+)单晶闪烁体与SrSO4∶Dy3+粉末样品的热释光谱及辐射发光光谱。观察到LYSO∶Ce3+在108, 200, 380 K左右的热释光峰, 发光波长位于390~450 nm之间, 是明显的宽带峰。在低温下由于基质的自陷激子(STE)发射所形成的发射峰在166 K时发生猝灭。在309 K时, Ce3+发射峰展宽为单一发射峰; SrSO4∶Dy3+发光峰温度为178, 385 K, 发光波长由Dy3+离子的能级跃迁决定, 在480, 575, 660, 750 nm处呈现窄带发光峰。结果表明, 系统人机交互界面友好, 实验数据可靠, 智能化程度高, 操作简单。

Abstract

To analyze the trap level at low temperature and obtain more information about the defect structure of materials, a low-temperature thermoluminescence(TL) spectrum measurement system based STM32 micro-controller was developed. Low-temperature sample chamber was designed and the samples were cooled by liquid nitrogen. The heating current was controlled by STM32 so that TL glow curves or three-dimensional(3D) TL spectra were obtained at a constant heating rate. The system has a high-precision temperature range of 85-400 K and the heating rate ranges from 0.1-10 K/s. The drive circuit of X-ray and ultraviolet light controlled by STM32 are designed for sample excitation. A CCD and a PMT are installed in the system to obtain two-dimensional(2D) TL glow curves and 3D TL spectrum respectively. In this paper, the system is used to test the TL and radioluminescence(RL) of (Lu,Y)2SiO5∶Ce3+ (LYSO∶Ce3+) scintillator and SrSO4∶Dy3+. The luminescence around 108, 200, 380 K is observed in LYSO∶Ce3+. The emission band is between 390 and 450 nm, which is a clear broad-band spectra. The emission peak due to the self-trapped excitons(STE) from host at low-temperature quenches above 166 K. The emission peaks of Ce3+ broaden into a single peak at 309 K, the emission peaks of SrSO4∶Dy3+are at 178, 385 K and the wavelength are 480, 575, 660, 750 nm due to the energy transitions of Dy3+, they are narrow-band spectra. The system can provide some merits, such as friendly interface, credible experimental data, higher intelligentization and simple operations.

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唐桦明, 唐强, 毛日华, 谢建才. (Lu,Y)₂SiO₅∶Ce³⁺与SrSO₄∶Dy³⁺材料低温热释光及其测试仪器的研究[J]. 发光学报, 2018, 39(12): 1807. TANG Hua-ming, TANG Qiang, MAO Ri-hua, XIE Jian-cai. Low-temperature Thermoluminescence of (Lu,Y)₂SiO₅∶Ce³⁺ and SrSO₄∶Dy³⁺ and Their Measurement Instruments[J]. Chinese Journal of Luminescence, 2018, 39(12): 1807.

(Lu,Y)₂SiO₅∶Ce³⁺与SrSO₄∶Dy³⁺材料低温热释光及其测试仪器的研究

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