Investigation of the abnormally-high annihilation rate of ortho-positronium in iodomethane gas

虽然对碘甲烷气体中正电子离子异常高湮灭速率的机理尚未揭示，但通过研究发现了以往报道的所有气态原子和分子的吸灭截面与由黏度推导出的几何截面之间的基本比例关系。在此基础上，提出了一个将正电子寿命与正电子捕获的自由空间的平均大小联系起来的实用理论。

Although the mechanism of the abnormally high annihilation rate of ortho-positronium in iodomethane gas has not been revealed, a fundamental proportional relationship between the pick-off quenching cross-section and the geometrical cross section derived from the viscosity has been found for all the gaseous atoms and molecules previously reported through the study. Based on this result, a practical theory, which relates the positronium lifetime to the average size of free spaces in which positronium trapped, has been proposed.