Investigation of background electron emission in the LUX detector
Investigation of background electron emission in the LUX detector
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DOI：
10.1103/physrevd.102.092004
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发表时间：
2020-11-10
影响因子：
5
通讯作者：
Zhang, C.
中科院分区：
文献类型：
--
作者：
Akerib, D. S.;Alsum, S.;Zhang, C.
目前用于直接探测暗物质实验的双相氙探测器已经观察到低能区背景电子事件的速率升高。虽然这种背景以各种方式对检测器性能产生负面影响，但其起源仅得到部分研究。在本文中，我们报告了一个系统的调查中观察到的LUX暗物质实验的电子病理学。我们根据它们的发射强度和它们与探测器中先前能量沉积的相关性来表征不同的电子种群。通过对不同实验条件下的背景研究，确定了主要的发光机制，包括氙发光引起的光电离和光电效应、被捕获在液体表面下的电子的延迟发射、杂质对漂移电子的捕获和释放以及栅极电子发射。我们将讨论如何在LUX和未来的氙暗物质实验中减轻这些背景。
Dual-phase xenon detectors, as currently used in direct detection dark matter experiments, have observed elevated rates of background electron events in the low energy region. While this background negatively impacts detector performance in various ways, its origins have only been partially studied. In this paper we report a systematic investigation of the electron pathologies observed in the LUX dark matter experiment. We characterize different electron populations based on their emission intensities and their correlations with preceding energy depositions in the detector. By studying the background under different experimental conditions, we identified the leading emission mechanisms, including photoionization and the photoelectric effect induced by the xenon luminescence, delayed emission of electrons trapped under the liquid surface, capture and release of drifting electrons by impurities, and grid electron emission. We discuss how these backgrounds can be mitigated in LUX and future xenon-based dark matter experiments.