Backgrounds and pulse shape discrimination in the ArDM liquid argon TPC
Backgrounds and pulse shape discrimination in the ArDM liquid argon TPC
复制标题
DOI：
10.1088/1475-7516/2018/12/011
复制
发表时间：
2018-12-01
影响因子：
6.4
通讯作者：
Wu, S.
中科院分区：
文献类型：
--
作者：
Calvo, J.;Cantini, C.;Wu, S.
ArDM实验完成了单相调试运行（ArDM运行I），使用了近一吨质量的活性液氩靶。通过对数据的分析以及与全探测器模拟预测的比较，可以提取探测器的特性并评估低背景条件。所用大气氩的Ar-39比活度测得为（0.95 +/- 0.05）Bq/kg。Canfranc地下站点的宇宙μ子通量被确定为（2-3.5）x 10（-3）m（-2）s（-1）。用Cf-252中子刻度源估算了脉冲形状判别法对电子反冲事件的统计抑制功率。电子和核反冲带的轮廓被发现是很好地描述高斯分布。采用这样一个模型，我们得出的电子反冲统计抑制功率超过10（8）吨级液态氩靶的事件超过50个探测到的光子在50%的核反冲接受值。室温下ArDM低温恒温器的Rn-222放射率为（65.6 +/- 0.4）μ Hz/l。这些结果代表了一个重要的物理里程碑的下一次运行中的双相模式，并在可预见的发展的背景下，对使用贫化氩靶。
The ArDM experiment completed a single-phase commissioning run (ArDM Run I) with an active liquid argon target of nearly one tonne in mass. The analysis of the data and comparison to predictions from full detector simulations allowed extraction of the detector properties and an assessment of the low background conditions. The Ar-39 specific activity from the employed atmospheric argon is measured to be (0.95 +/- 0.05) Bq/kg. The cosmic muon flux at the Canfranc underground site was determined to be in the range (2-3.5) x 10(-3) m(-2) s(-1). The statistical rejection power for electronic recoil events using the pulse shape discrimination method was estimated using a Cf-252 neutron calibration source. Electronic and nuclear recoil band profiles were found to be well described by Gaussian distributions. Employing such a model we derive values for the electronic recoil statistical rejection power of more than 10(8) in the tonne-scale liquid argon target for events with more than 50 detected photons at a 50% acceptance for nuclear recoils. The Rn-222 emanation rate of the ArDM cryostat at room temperature was found to be (65.6 +/- 0.4) mu Hz/l. These results represent an important physics milestone for the next run in the double-phase mode and in the context of foreseen developments towards the use of depleted argon targets.