【摘要】 锂掺杂塑料闪烁体不仅能够实现快中子和热中子的双模探测，还继承了传统塑料闪烁体低成本、可大体积制备的优势，近年来受到了广泛关注，尤其在热中子探测领域展现出广阔的应用前景。本研究采用热聚合法成功制备了甲基丙烯酸锂（Lithium Methacrylate,LiME）掺杂的聚苯乙烯（Polystyrene,PS）塑料闪烁体，并对其性能进行了全面表征。通过研究塑料闪烁体的辐射发光强度与引发剂偶氮二异丁腈（2,2’-Azobis(2-methylpropionitrile),AIBN）、主荧光染料2,5-二苯基噁唑（2,5-Diphenyloxazole,PPO）和移波剂1,4-双（5-苯基-2-噁唑基）苯（1,4-Bis(5-phenyl-2-oxazolyl)benzene,POPOP）的质量浓度相关性，实验确定了AIBN、PPO和POPOP在塑料闪烁体基质中的优化浓度分别为0.1%、2%和0.02%。基于这一优化配方，成功制备了尺寸为?33 mm×6 mm、LiME掺杂量的一系列高透光性塑料闪烁体样品，对其光学透过率、光致发光、辐射发光以及脉冲幅度谱响应等性能进行了详细表征。结果表明，制备的锂掺杂塑料闪烁体具有良好的光学质量，其发光峰位与纯塑料闪烁体相比偏移有限。然而，随着LiME掺杂量的增加，样品的荧光强度和相对光输出均呈现降低趋势。这一现象推测与掺杂过程引起的荧光猝灭效应有关。更多还原

【Abstract】 [Background] Lithium-doped plastic scintillators possess the dual-mode detection capability for both fast and thermal neutrons, and combine the advantages of conventional plastic scintillators such as cost-effectiveness and the ability to fabricate in large sizes, have drawn much attention and shown great potential for thermal neutron detection in recent years. [Purpose] This study aims to prepare large, trasparent polystyrene(PS) plastic scintillators doped with lithium methacrylate(LiME) via a thermal polymerization method, and to characterize their optical transmittance, luminescence, and pulse height spectrum response properties. [Methods] The composition, and structure of synthesized LiME were analyzed using Fourier transform infrared(FTIR) spectroscopy, Raman spectroscopy, and spectrophotometry. The transmittance, photoluminescence(PL) and X-ray excited luminescence(XEL) properties of LiME-doped plastic scintillators were measured and compared with those of pure plastic scintillator. The pulse height spectra(PHS) under excitation of gamma-ray were measured to determine values of the relative light output for the plastic scintillator by using Compton Edge calibration. [Results] The optimal concentrations of AIBN, PPO, and POPOP for polystyrene plastic scintillators were experimentally determined to be 0.1 wt%, and 0.02 wt%, respectively. Characterization results indicate that the LiME-doped plastic scintillators maintain excellent optical quality, with the peak position of the emission spectrum remaining consistent with that of the pure plastic scintillator. However, as the LiME content increases, both the fluorescence intensity and light output of the scintillator gradually decrease. This trend is presumed to be associated with fluorescence quenching effects induced by the doping process. [Conclusions] Large, transparent plastic scintillators doped with up to 12 wt% LiME(equivalent to 0.9 wt% Li) can be successfully synthesized using a thermal polymerization method. While the performance of lithium-doped plastic scintillators still requires further improvement, these materials hold great potential for applications requiring efficient dual-mode detection of both fast and thermal neutrons.更多还原