New Lanthanide-Containing Silicate Fluoride Scintillators for Radiation Detection

非技术性边境保护机构，如国土安全部，必须能够检测流氓辐射源，例如脏弹，在它们被运送到该国之前。迫切需要大量的被称为增透剂的材料，其用于便携式检测设备中。闪烁体是在暴露于辐射时发出可见光的材料，闪烁体越好，光线越亮，可检测到的放射性物质越少。这项研究由NSF材料研究部的固态和材料化学计划资助，涉及改进的结晶材料的晶体生长的基本方面，从而推动了辐射探测领域的发展。此外，本研究项目为研究生和本科生提供了宝贵的教育经验。进行这项研究训练学生在晶体生长的艺术，教他们实验设计和方法优化的概念。总的来说，这项研究有助于教育和培训范围广泛的个人，包括那些来自代表性不足的群体，在固态和材料化学领域。TechnicalOne area where the development of new functional materials can have a tremendous impact is homeland security.迫切需要大量有效的吸收材料来改善辐射检测。本研究的重点是合成新的中子、X射线和γ射线活化的氧化物。混合阴离子相中的氟已被确定为在荧光强度中起关键作用的一种元素，并且已证明氟还可以增加稀土硅酸盐的闪烁效率。具体地，已知其中氟阴离子位于LnOxFy多面体中的发光氟氧化物，例如最近发现的明亮发光材料Cs3LnSi4O10F2（Ln = Eu，Tb），可以表现出与Lu2SiO5：Ce3+一样明亮的闪烁。含氟混合阴离子相的目标晶体生长利用了最近开发的增强熔剂生长技术，该技术已知可产生氟氧化物和含盐硅酸盐的晶体。为了更好地理解在用于合成复合氧化物单晶的各种通量环境中形成混合阴离子相所涉及的过程，进行了原位中子衍射实验以确定用于在实验室中制备新的晶体生长剂的最佳生长条件，以及将晶体生长从经验过程转变为深思熟虑的过程。此外，这项研究有助于教育和培训范围广泛的个人，包括那些来自代表性不足的群体，在固态和材料化学领域，例如通过与克拉夫林大学，HBCU机构的合作。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Non-TechnicalBorder protection agencies, such as Homeland Security, must be able to detect rogue radiation sources, for example dirty bombs, before they are transported into the country. A pressing need exists for large quantities of materials know as scintillators, which are used in portable detection devices. Scintillators are materials that emit visible light when exposed to radiation, and the better the scintillator, the brighter the light and the smaller the amount of radioactive material that can be detected. This research, funded by the Solid State and Materials Chemistry Program in the Division of Materials Research at NSF, involves the fundamental aspects of crystal growth of improved scintillating materials and thereby advances the field of radiation detection. In addition, this research project provides a valuable educational experience for graduate and undergraduate students. Conducting this research trains students in the art of crystal growth and teaches them the concept of experimental design and methods optimization. Overall, this research contributes to the education and training of a wide range of individuals, including those from underrepresented groups, in the area of solid state and materials chemistry.TechnicalOne area where the development of new functional materials can have a tremendous impact is homeland security. There exists a pressing need for large quantities of efficient scintillating materials for improved radiation detection. This research focuses on the synthesis of new neutron, X-ray, and gamma-ray activated scintillating oxides. Fluorine in mixed anion phases has been identified as one element that plays a crucial role in the intensity of fluorescence, and it has been demonstrated that fluorine can also increase the scintillation efficiency of rare earth silicates. Specifically, it is known that luminescent oxyfluorides in which the fluorine anions are located in LnOxFy polyhedra, such as in Cs3LnSi4O10F2 (Ln = Eu, Tb), a recently discovered brightly scintillating material, can exhibit scintillation as bright as Lu2SiO5:Ce3+. The targeted crystal growth of fluorine containing mixed-anion phases takes advantage of a recently developed enhanced flux growth technique that is known to yield crystals of oxyfluorides and salt-inclusion silicates. To better understand the processes involved in the formation of mixed anion phases in the various flux environments that are used for synthesis of complex oxide single crystals, in-situ neutron diffraction experiments are carried out to identify the optimal growth conditions for preparing new scintillators in the laboratory as well as to transform crystal growth from an empirical to a deliberate process. Additionally, this research contributes to the education and training of a wide range of individuals, including those from underrepresented groups, in the area of solid state and materials chemistry, for example through collaboration with Claflin University, an HBCU institution.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.