【摘要】 慢正电子在薄膜材料、材料表面和界面的缺陷研究中具有重要应用。慢正电子束流通过慢化常规正电子束流获取，慢化效率问题是目前限制慢正电子束流发展的重要因素。本文通过将磁镜和钨箔慢化体结合起来，研究提高慢化效率的方法。本文设计并搭建了一套基于0.1 T磁镜的正电子慢化装置，并展开相应慢化实验，通过测量不同磁镜条件下装置终端慢正电子计数率来分析磁镜对慢化效率的提升效果；采用G4beamline软件进行蒙特卡罗模拟，探究准直器内径和位置对传输性能的影响，并计算装置慢化效率。实验结果表明，磁镜可将装置的慢化效率提高90%左右，实验慢化效率为（0.059±0.005）%。本文研究结果验证了磁镜提高装置慢化效率的可行性，并为进一步优化正电子慢化效率提供了依据。更多还原

【Abstract】 [Background] Slow positrons have significant applications in the study of defects in thin-film materials, material surfaces, and interfaces. Slow positron beams are obtained by moderating conventional positron beams, where the moderation efficiency is currently a major factor limiting the development of slow positron beams. [Purpose] This study aims to investigate methods for enhancing moderation efficiency by integrating a magnetic mirror with a tungsten foil moderator. [Methods] A positron moderation device based on a 0.1 T magnetic mirror was designed and constructed, and corresponding moderation experiments were conducted. Then, the enhancement effect of the magnetic mirror on moderation efficiency was analyzed by measuring the slow positron count rate at the device terminal under different magnetic mirror configurations. Finally, the G4 beamline software was used for Monte Carlo simulation to explore the influence of the collimator inner diameter and position on the transmission performance, and the moderation efficiency of the device was subsequently calculated. [Results] The experimental results demonstrate that the magnetic mirror can enhance the moderation efficiency of the device by nearly 90%. The measured experimental moderation efficiency is determined to be(0.059±0.005)%. [Conclusions] The findings of this study validate the feasibility of utilizing a magnetic mirrors to improve the moderation efficiency of such devices, providing a foundation for further optimization of positron moderation efficiency.更多还原