Correlated single- and few-electron backgrounds milliseconds after interactions in dual-phase liquid xenon time projection chambers
Correlated single- and few-electron backgrounds milliseconds after interactions in dual-phase liquid xenon time projection chambers
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DOI：
10.1088/1748-0221/16/07/p07014
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发表时间：
2021-03
影响因子：
1.3
通讯作者：
A. Kopec;Amanda L. Baxter;M. Clark;R. Lang;Shengchao Li;Juehang Qin;Riya Singh
中科院分区：
文献类型：
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作者：
A. Kopec;Amanda L. Baxter;M. Clark;R. Lang;Shengchao Li;Juehang Qin;Riya Singh
我们描述了在双相液态氙时间投影室中观察到的单电子和少电子背景，其时间尺度大大超过相互作用后的最大漂移时间。这些仪器背景限制了探测器对暗物质和宇宙中微子的灵敏度。利用普渡大学的~ 150 g液态氙探测器，我们研究了122 keV 57Co Compton相互作用后产生的这些背景在不同的探测器条件下的行为。我们发现，在相互作用后，单电子和少电子信号的速率随时间的变化遵循幂律。随着萃取场的增大，萃取率呈线性增加。单电子背景下的速率随漂移场增大的关系尚不清楚。将速率归一化到主相互作用的测量电离信号，速率随相互作用的深度线性增加。我们测试了红外光子（1550 nm）会通过与杂质的光分离来刺激和加速电子发射的假设，但发现即使是1瓦的红外光也不能减少这些背景。因此，我们提供了一种特征，可以为低能量罕见事件搜索的背景模型提供信息。
We characterize single- and few-electron backgrounds that are observed in dual-phase liquid xenon time projection chambers at timescales greatly exceeding a maximum drift time after an interaction. These instrumental backgrounds limit a detector's sensitivity to dark matter and cosmogenic neutrinos. Using the ∼ 150 g liquid xenon detector at Purdue University, we investigate how these backgrounds, produced after 122 keV 57Co Compton interactions, behave under different detector conditions. We find that the rates of single- and few-electron signals follow power-laws with time after the interaction. We observe linearly increasing rates with increased extraction field. The relationship of the rates in the single-electron background with increased drift field is unclear. Normalizing the rates to the primary interaction's measured ionization signal, the rates increase linearly with the depth of the interaction. We test the hypothesis that infrared photons (1550 nm) would stimulate and accelerate electron emission via photodetachment from impurities, but find that even 1 Watt of infrared light fails to reduce these backgrounds. We thus provide a characterization that can inform background models for low-energy rare event searches.