发表机构
The Center for High Energy Physics, Kyungpook National University; Advanced Radiation Technology Insititute, Korea Atomic Energy Research Insititute; Department of Physics, Kyungpook National University; Center for Underground Physics, Institute for Basic Science; Central Research Institute, Korea Hydro & Nuclear Power Co., Ltd.; State Key Laboratory of Functional Crystals and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences（韩国庆北国立大学高能物理中心; 韩国原子能研究所先进辐射技术研究所; 韩国庆北国立大学物理系; 韩国基础科学研究院地下物理中心; 韩国水力核电有限公司中央研究院; 中国科学院上海硅酸盐研究所功能晶体及器件国家重点实验室）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
KAPAE二期探测器通过Geant4优化几何、评估闪烁体性能并研究温度影响，用于搜索正电子素不可见衰变；地下本底降至地表千分之一以下。
AI 中文摘要
KAPAE二期探测器旨在搜索正电子素的不可见衰变，以此作为超越标准模型物理的探针。通过Geant4模拟优化了探测器几何结构，并实验评估了闪烁体及读出性能。研究了BGO闪烁体的温度依赖性及多种读出配置，以确定提供最佳能量分辨率的工作条件。随后在地表及地下测量了本底水平。在地表，正电子-伽马符合本底约为1赫兹，偶尔出现高达约65赫兹的突发。在地下，本底降至低于约3×10⁻⁴赫兹，降低了三个数量级以上。
英文摘要
The KAPAE Phase II detector was developed to search for invisible decays of positronium as a probe of physics beyond the Standard Model. The detector geometry was optimized with Geant4 simulations, and the scintillation and readout performance were evaluated experimentally. The temperature dependence of the BGO scintillator and several readout configurations were studied to find the operating condition giving the best energy resolution. The background level was then measured both at the surface and underground. At the surface, the positron-gamma coincidence background was of order 1 Hz, with occasional bursts up to about 65 Hz. Underground, it decreased to below about 3 \times 10^{-4} Hz, more than three orders of magnitude lower.
Comments32 pages, 16 figures
