SEARCH FOR ULTRA-FAST, HEAVY-ATOM SCINTILLATORS

这项研究的目的是发现新的闪烁体 发射速度快、原子序数高、密度高、光度高。 具体地说，我们寻找一种具有光峰探测的闪烁体 BGO的效率、BaF2的时间分辨率和BGO的光度 NaI(T1)。我们的最终目标是大幅提高能力 通过提供高光刻效率来实现正电子发射断层扫描 和良好的空间分辨率，飞行时间的优势 信息，以及用于散射抑制的良好的脉冲高度分辨率。在……里面 此外，单光子断层扫描和常规核医学 成像将受益于具有更高阻挡能力的闪烁体 并且比NaI(T1)的停滞时间短。 我们已经开发出一种方法，能够快速筛选数百个潜在的 化合物不需要昂贵和耗时的种植步骤 闪烁质量的晶体。该方法使用20-30的100 ps脉冲串 来自桌面脉冲X射线发生器的keV X射线，以测量 任何荧光发射的强度、衰减时间和发射光谱 从粉状样本中提取。我们还将执行分子轨道 预测候选者闪烁特性的计算 材料(包括掺杂和非掺杂化合物)，并使用这些理论 用来指导我们搜索的预测。最后，许多候选人 化合物(特别是掺杂化合物)不能在市场上买到， 因此，我们将合成大量我们测试的化合物。

The objective of this research is to discover new scintillators with very rapid emissions, high atomic number, high density, and high luminosity. Specifically, we seek a scintillator with the photopeak detection efficiency of BGO, the timing resolution of BaF2, and the luminosity of NaI(T1). Our ultimate goal is to improve substantially the capabilities of positron emission tomographs by providing high photopeak efficiency and good spatial resolution, the advantages of time-of-flight information, and good pulse height resolution for scatter rejection. In addition, single photon tomography and conventional nuclear medicine imaging would benefit from a scintillator having higher stopping power and less dead time than NaI(T1). We have developed a method able to rapidly screen hundreds of potential compounds without the costly and time-consuming step of growing scintillation quality crystals. This method uses 100 ps bursts of 20-30 keV X-rays from a table-top pulsed x-ray generator to measure the intensity, decay time, and emission spectrum of any fluorescent emissions from powdered samples. We will also perform molecular orbital computations to predict the scintillation properties of candidate materials (both doped and undoped compounds), and use these theoretical predictions to guide our search. Finally, many of the candidate compounds (especially doped compounds) are not commercially available, and so we will synthesize a large number of the compounds that we test.