标题： 高灵敏度氡析出测量系统的开发与表面处理优化 显示英文标题

标题： Development of High-Sensitivity Radon Emanation Measurement Systems with Surface Treatment Optimization

摘要： 氡及其子体是稀有事件探测实验中的重要背景来源，包括暗物质搜索实验，如PandaX-4T实验，以及其他稀有衰变研究，如无中微子双β衰变（NLDBD）。为了测量和控制这些实验中的氡析出，我们开发了两种专门的氡测量系统：一种是适用于小尺寸样品的氡析出测量系统，在12.3升计数室中的本底率为$0.03 \pm 0.01$mBq，另一种是专为大体积样品设计的氡捕集系统，采用低温氡捕集技术，通过1标准升每分钟（slpm）气体流量和6小时捕集时间将灵敏度提高了30倍。为了提高探测灵敏度，研究了各种腔体表面处理方法，包括机械抛光、电化学抛光和镜面抛光，结果表明更光滑的表面会导致更低的氡析出率。此外，对不锈钢腔体进行环氧涂层处理和用镀铝聚酯薄膜覆盖也可以分别将氡析出减少$90 \pm 7)\%$和$60 \pm 12)\%$。 显示英文摘要

摘要： Radon and its progenies are significant sources of background in rare event detection experiments, including dark matter searches like the PandaX-4T experiment and other rare decay studies such as neutrinoless double beta decay (NLDBD). In order to measure and control radon emanation for these experiments, we have developed two specialized radon measurement systems: a radon emanation measurement system suitable for small-sized samples with a blank rate of $0.03 \pm 0.01$ mBq in the 12.3 L counting chamber, and a radon trap system designed for large-volume samples using low-temperature radon trapping techniques, which improves the sensitivity by a factor of 30 with 1 standard liter per minute (slpm) gas flow and 6 hours trapping time. To boost the detection sensitivity, various surface treatments of the chambers were investigated, including mechanical polishing, electrochemical polishing, and mirror polishing, which reveals that smoother surfaces lead to lower radon emanation rates. In addition, treatments such as applying epoxy coating and covering with aluminized Mylar to stainless steel chambers can also reduce the radon emanation by ($90 \pm 7)\%$ and ($60 \pm 12)\%$, respectively.