论文标题
通过液体氩过滤系统观察微酮中缓解ra
Observation of Radon Mitigation in MicroBooNE by a Liquid Argon Filtration System
论文作者
论文摘要
微酮液体氩时间投影室(LARTPC)通过使用过滤系统维持高水平的液体氩气纯度,该过滤系统可以去除连续循环液体中的电负污染物,恢复沸腾的沸腾和外部提供的氩气。我们使用微酮LARTPC来重建MEV尺度放射学衰变。使用此技术,我们测量了液体氩过滤系统在去除ra时的功效。通过将500 kBQ $^{222} $ rn源上游进行了研究,并搜索LARTPC中的放射学衰变数量的增加。在通过液体氩过滤系统缓解ra的两个模型的背景下,一种减慢机制和捕获机制,微酮数据分别支持减少ra的减少因子,分别大于99.999%或97%。此外,对过滤器的放射学调查发现,基于铜的过滤器材料是去除$^{222} $ rn的主要介质。这是对液体氩具有大规模铜的过滤器的第一次观察,可以为将来的大型LARTPC提供缓解溶液。
The MicroBooNE liquid argon time projection chamber (LArTPC) maintains a high level of liquid argon purity through the use of a filtration system that removes electronegative contaminants in continuously-circulated liquid, recondensed boil off, and externally supplied argon gas. We use the MicroBooNE LArTPC to reconstruct MeV-scale radiological decays. Using this technique we measure the liquid argon filtration system's efficacy at removing radon. This is studied by placing a 500 kBq $^{222}$Rn source upstream of the filters and searching for a time-dependent increase in the number of radiological decays in the LArTPC. In the context of two models for radon mitigation via a liquid argon filtration system, a slowing mechanism and a trapping mechanism, MicroBooNE data supports a radon reduction factor of greater than 99.999% or 97%, respectively. Furthermore, a radiological survey of the filters found that the copper-based filter material was the primary medium that removed the $^{222}$Rn. This is the first observation of radon mitigation in liquid argon with a large-scale copper-based filter and could offer a radon mitigation solution for future large LArTPCs.