SEARCH FOR ULTRA FAST, HEAVY ATOM SCINTILLATORS

描述(改编自申请者摘要)：主要目标 这项研究是对新闪烁体的发现，具有非常快的速度 发射，以及高原子序数、密度和光度。闪烁体 具有比Lu2SiO5：Ce更高的原子序数和光度，以及衰变时间 &lt；1 ns将提高探测效率、空间分辨率和散射度 拒绝正电子断层扫描，并提高了正电子断层扫描的准确性 通过提供飞行时间信息重建图像。其他内容 目标包括发现具有更高停止时间的闪烁体 与NaL(TI)相比，单光子断层扫描的功率和死区时间更短，并且 具有较低的余辉和较长波长的高光输出(其中 硅光电探测器具有最高的效率)用于X射线计算 体层摄影术。在这个项目的过程中，他们发现了 闪烁体CeF3和PbWO4(这两种闪烁体正在大规模生产 能量物理)，以及BaCl2，LuAlO3：Ce，LuBO3：Ce，其晶体生长是 正在调查中。为了实现这些目标，他们将继续 在化学计量比选择中使用经验和计算指导 并对掺杂化合物进行合成和测量。他们建造了一个脉冲式的 专为测量粉末闪烁而设计的X射线源 以及来自具有高灵敏度和定时分辨率的晶体样品 &lt；120 ps。他们将使用可用的分子轨道计算机代码来 调查启用或禁止闪烁的过程(空穴传输， 激子形成、激活剂原子激发、热猝灭等) 并开发计算方法，以便有效地选择 用于合成和测试的化合物。

DESCRIPTION (Adapted from Applicant's Abstract): The primary objective of this research is the discovery of new scintillators with very rapid emissions, and high atomic number, density, and luminosity. A scintillator with higher atomic number and luminosity than Lu2SiO5:Ce, and a decay time <1ns would improve the detection efficiency, spatial resolution, and scatter rejection of positron tomographs, and improve the accuracy of the reconstructed images by providing time-of-flight information. Additional objectives include the discovery of scintillators having higher stopping power and less dead time than Nal(TI) for single photon tomography, and having low afterglow and high light output at longer wavelengths (where silicon photodetectors have their highest efficiency) for x-ray computed tomography. During the course of this project, they have discovered the scintillators CeF3 and PbWO4 (which are in large scale production for high energy physics), and BaCI2, LuAIO3:Ce, LuBO3:Ce, whose crystal growth is under investigation. To accomplish these objectives, they will continue to use empirical and computational guidance in the selection of stoichiometric and doped compounds to synthesize and measure. They have built a pulsed x-ray source specifically designed to measure scintillation from powders as well as from crystal samples with high sensitivity and a timing resolution <120 ps. They will use available molecular orbital computer codes to investigate processes that enable or prohibit scintillation (hole transport, exciton formation, excitation of activator atoms, thermal quenching, etc.) and to develop computational methods for the efficient selection of compounds for synthesis and testing.