标题： 正电子-电子对湮灭中的三光子衰变观测：用于本科实验室的三重符合设置 显示英文标题

标题： Observation of triple-photon decay in positron-electron pair annihilation: a triple coincidence setup for the undergraduate laboratory

摘要： 正电子-电子对湮灭产生两个光子是PET扫描仪众多应用中的一种。 从标准密封源中通过多于两个光子的正电子素（Ps）衰变较为少见，但可以通过相对简单的设置进行观察。 本实验的主要目标是通过正电子素的湮灭验证亚原子层面的动量和总角动量守恒原理。 正电子素的两种自旋构型由β+源产生。 通过双和三重符合设置中的伽马射线谱学技术来识别衰变模式。 需要三个高纯锗探测器（或两个高纯锗和一个NaI(Tl)探测器）以及数字电子系统。 显示英文摘要

摘要： The positron-electron pair annihilation in two photons is known for its numerous applications using PET scanners. The decay of Positronium (Ps) from a standard sealed source in more than two photons is less likely but can be observed with a relatively simple setup. The main goal of this experiment was to verify momentum and total angular momentum conservation principles at subatomic level through the Ps annihilation. The two spin configurations of Ps are produced with a beta+ source. The decay modes are identified using gamma-ray spectroscopy techniques in a double and triple coincidence setup. Three germanium detectors (or two HPGe and one NaI(Tl) detectors) and a digital electronic system are required.