Gu Mu

The Luminescence of a CuI Film Scintillator Controlled by a Distributed Bragg Reflector

We investigate the emission properties of CuI film scintillators and the effect of distributed Bragg reflectors. The free-exciton emission and the donor-acceptor pair emission from the CuI thin film with the peak wavelengths of 410 nm and 420 nm are observed. However, for the two emission bands, the distributed Bragg reflector reflection results in different enhancements, which is interpreted by the varying transmittance with wavelength. Angle-dependence of emission profile is decided by the transmittance and DBR reflection, which may be useful in scintillation detection applications.

Theoretical Calculations on Rare Earth Elements in Barium Fluoride Crystal

In the present work we used Hartree-Fock-Slater local-density discrete variational method to calculate the energy level of some rare earth doped BaF2 crystals and proposed that the Eu, Dy and Yb elements will change their valence from +3 to +2 under irradiation and thus change the optical properties of the crystals. The results show that this radiation effect model is in good agreement with experiments.

The Mechanism of Slow Component Suppression in Lanthanum Doped Barium Fluoride Crystal

The electronic structures of pure BaF{sub 2} crystal and lanthanum doped BaF{sub 2} crystal have been calculated in a self-consistent molecular-cluster model. The cluster is embedded in the crystal lattice and the entire system treated iteratively in the Hartree-Fock-Slater local-density theory. As lanthanum doped BaF{sub 2} is concerned, the obtained results revealed that the F{sub i}{sup {minus}} which is introduced by the lanthanum may contribute to the suppression of the slow component in the scintillation light of BaF{sub 2} crystal.

The radiation effect mechanism of some rare earth doped BaF{sub 2} crystal

Barium fluoride (BaF{sub 2}) was discovered to be a fast inorganic scintillator in 1983. Considerable attention has been attracted in the fields of nuclear physics, nuclear medicine and high energy physics due to its high density, short radiation length, non-hygroscopic nature and high detection efficiency for {gamma}-rays. However, when BaF{sub 2} is exposed to a radiation environment, the fluorescence output will decrease, thus the study of the radiation damage mechanism of BaF{sub 2} is quite important. In this paper, the authors used the Discrete Variational X{sub {alpha}} (DV-X{sub {alpha}}) method to calculate the energy level of some rare earth doped BaF{sub 2} crystals and indicated that the Eu, Dy and Yb elements will change their valence from +3 to +2 under irradiation and thus change the optical properties of the crystals. The results show that this radiation effect model presented agree well with experiments.

LuTaO 4 :Ln 3+ (Ln=Eu,Tb)透明薄膜制备改进与其发光性能研究

LuTaO 4 是一种新型的辐射探测材料, 但是制备高质量的透明薄膜面临着巨大挑战。为了在保证薄膜不开裂与高透明度的前提下提高薄膜的厚度, 通过大量摸索选用聚乙烯吡咯烷酮(PVP)为胶黏剂并优化溶胶中固含量及PVP含量成功制备出单层厚度达到100 nm的LuTaO 4 :Ln 3+ (Ln=Eu,Tb)薄膜, 保证了薄膜的透明度同时大大提高了发光性能。该方法为高质量LuTaO 4 :Ln 3+ (Ln=Eu,Tb)厚膜的制备和应用奠定了基础。

Lu 2 SiO 5 : Ce 3+ 透明薄膜制备及其发光性能研究

Lu 2 SiO 5 : Ce 3+ 薄膜具有高光产额、快衰减时间、高密度、高空间分辨率等优点, 有望成为X射线探测中的闪烁材料, 但制备高质量的薄膜面临挑战。本工作采用溶胶凝–胶法, 通过对制备过程中水硅比、烧结程序、胶黏剂和固含量等四个因素的系统研究与分析, 结果表明: 在空气湿度为85%, 溶胶水硅比为6.6条件下, 适量添加PEG400, 采用优化后最佳固含量, 从450℃开始进行烧结程序后退火, 可制备出具有透明、平整、无裂痕的高质量Lu 2 SiO 5 : Ce 3+ 闪烁薄膜, 单次旋涂获得的膜厚达到167 nm。实验表明水含量是引起薄膜发白的主要因素; 烧结程序决定了薄膜的有机物分解程度及结晶状况; 溶胶固含量及胶黏剂含量是调控薄膜厚度的重要方法。本工作为Lu 2 SiO 5 : Ce 3+ 闪烁薄膜的实际应用奠定了基础。