ARI: Synthesizing Conjugated Polymers with High Scintillation Light Yield

1348403 （Pei）为有效应对潜在的放射性和核威胁，需要广泛部署具有辐射源高灵敏度同位素识别功能的传感器。提供伽马射线能谱和中子和伽马辨别的探测器是核传感的关键。该项目旨在开发一种新型聚合物闪烁体，具有与无机晶体相当的高灵敏度，同时保持极低的生产成本。这种闪烁体可以在全国范围内广泛部署？美国的港口和大型公共场所，以防止安全威胁。目前的辐射探测器大多基于单晶无机半导体或闪烁体，它们都不能满足高灵敏度、能量分辨率、可现场性和低成本的要求。本提案旨在开发一种合成共轭聚合物单体的基本方法，其闪烁性能可与无机单晶闪烁体相媲美。通过热固性聚合可以在模具中以极低的生产成本合成单体。该研究将研究具有大三重态能级的共轭化合物和聚合物作为主体材料，将单重态和三重态激子转移到蓝色磷光荧光中，以获得高闪烁光产量。将熔融溶液共聚作为一种有效的技术进行研究，以合成体积大小的透明整体，添加剂分布均匀，团聚可以忽略不计。该项目的目标是展示透明共轭聚合物单体，其目标光产率为100,000/MeV，是目前商用塑料闪烁体的近10倍。对中子粒子和伽马射线具有高吸收截面的增感剂也将用于高灵敏度和中子-伽马脉冲鉴别。这项工作是基于对透明聚合物单体的初步研究，其测量的光产率已经是商业塑料闪烁体的4.6倍。所提出的共轭聚合物闪烁体具有高闪烁光产率和低生产成本，将在国土安全、医学成像和空间探索等领域开辟广泛的新应用。研究成果将迅速传播，项目开发的技术目标是转让，以便迅速商业化。该项目将对从高中到博士研究生的教育和指导产生影响。教育和培训具有材料科学和核材料相互作用双重专业的本科生和研究生是项目活动的一部分。研究生和博士后将有机会在合作的国家实验室实习，获得第一手的辐射检测经验。

1348403 (Pei) Effective counter measures against potential radioactive and nuclear threats call for a wide-spread deployment of sensors with high-sensitivity isotopic identification of radiation sources. Detectors providing gamma ray spectroscopy and neutron and gamma discrimination are keys in nuclear sensing. This project aims to develop a new polymer scintillator that exhibits high sensitivity comparable to inorganic crystals while maintaining an extremely low production cost. The scintillators could be widely deployed at the nation?s ports and large public venues to deter security threats. Current radiation detectors are mostly based on single crystal inorganic semiconductors or scintillators, none of which satisfy the demanding requirements of high sensitivity, energy resolution, fieldability, and low cost. This proposal aims at developing a fundamental approach to the synthesis of conjugated polymer monoliths with scintillation performance comparable to inorganic single crystal scintillators. The monoliths can be synthesized by thermosetting polymerization in a mold at extremely low production cost. The research will investigate conjugated compounds and polymers with large triplet energy levels as the host material to transfer both singlet and triplet excitons to a blue phosphorescent fluor for high scintillation light yield. Copolymerization of molten solutions will be studied as an effective technique to synthesize bulk-size transparent monoliths with uniform distribution of additives and negligible aggregation. The objective of the project is to demonstrate transparent conjugated polymer monoliths with a target light yield of 100,000/MeV, an improvement of almost 10 times that of current commercial plastic scintillators. Sensitizing agents with high absorption cross-sections for neutron particles and gamma rays will also be investigated for high sensitivity and neutron-gamma pulse discrimination. The work is based on preliminary research on transparent polymer monoliths with a measured light yield that is already 4.6 times that of a commercial plastic scintillator. The proposed conjugated polymer scintillators with high scintillation light yield and low production cost will open up a wide range of new applications important to homeland security, medical imaging, and space exploration. The research findings will be rapidly disseminated, and the technology developed in the project is targeted to be transferred for rapid commercialization. The project will have impact on education and mentoring of students from high schools up to doctoral candidates. Education and training of undergraduate and graduate students with dual specialties of materials science and nuclear-material interactions is part of the project activities. Graduate students and postdoctoral fellows will have the opportunity to intern in the collaborating national labs to gain firsthand experience with radiation detection.