A study of positron capture in a two-(pressure) stage buffer gas accumulation apparatus is presented for a variety of species, including some molecules which are known to be either efficient for positron trapping, or are frequently used to cool the particles when held in these devices. Absolute accumulation efficiencies are reported for all species. A detailed optimisation procedure, which has identified the main processes responsible for positron capture and loss in the trap, has been deployed to explore accumulation efficiency as the gas pressure and the electrostatic well depth in the trap are systematically varied. Accumulation exploiting energy loss via molecular vibrational transitions has been observed for the first time for a number of gases, though at much lower efficiency than achieved using electronic excitation processes.

中文翻译：

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正电子的缓冲气体捕获研究

提出了一种在两级（压力）缓冲气体累积装置中对正电子俘获的研究，涉及多种物种，包括一些已知对正电子俘获有效的分子，或者被固定在其中时常用于冷却颗粒的分子。这些设备。报告了所有物种的绝对累积效率。随着系统地改变阱中的气压和静电井深度，详细的优化程序已经确定了导致阱中正电子捕获和损失的主要过程，已被用于探索积累效率。首次观察到许多气体利用通过分子振动跃迁的能量损失进行蓄积，尽管效率远低于使用电子激发过程获得的效率。