CoGeNT: A search for low-mass dark matter using p-type point contact germanium detectors
CoGeNT: A search for low-mass dark matter using p-type point contact germanium detectors
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DOI：
10.1103/physrevd.88.012002
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发表时间：
2013-07-08
影响因子：
5
通讯作者：
Yocum, K. M.
中科院分区：
文献类型：
--
作者：
Aalseth, C. E.;Barbeau, P. S.;Yocum, K. M.
CoGeNT 采用 p 型点接触 (PPC) 锗探测器来搜索弱相互作用大质量粒子 (WIMP)。凭借其低能量阈值和抑制表面背景的能力，这种类型的设备可以重点关注低质量暗物质候选者（m(chi) 类似于 10 GeV/c(2)）。我们报告了目前在苏丹地下实验室采集数据的 PPC 探测器的特点，详细阐述了屏蔽、数据采集、仪器稳定性、数据分析和背景估计等方面。详细的背景模型用于研究先前报告的事件的低能量过剩，并评估低能量事件率的时间调制的可能性。对所有目前已知背景的广泛模拟并不能为 CoGeNT 数据中过多的低能量事件或先前观察到的事件率的时间变化提供可行的背景解释。还首次报道了数据中表面（慢脉冲上升时间）事件污染作为能量函数的确定。我们得出的结论是，CoGeNT 探测器技术非常适合搜索 WIMP 质量区域中的暗物质粒子相互作用以及 DAMA/LIBRA 结果所支持的耦合所预期的年度调制特征。
CoGeNT employs p-type point-contact (PPC) germanium detectors to search for weakly interacting massive particles (WIMPs). By virtue of its low-energy threshold and ability to reject surface backgrounds, this type of device allows an emphasis on low-mass dark matter candidates (m(chi) similar to 10 GeV/c(2)). We report on the characteristics of the PPC detector presently taking data at the Soudan Underground Laboratory, elaborating on aspects of shielding, data acquisition, instrumental stability, data analysis, and background estimation. A detailed background model is used to investigate the low-energy excess of events previously reported and to assess the possibility of temporal modulations in the low-energy event rate. Extensive simulations of all presently known backgrounds do not provide a viable background explanation for the excess of low-energy events in the CoGeNT data or the previously observed temporal variation in the event rate. Also reported for the first time is a determination of the surface (slow pulse rise time) event contamination in the data as a function of energy. We conclude that the CoGeNT detector technology is well suited to search for the annual modulation signature expected from dark matter particle interactions in the region of WIMP mass and coupling favored by the DAMA/LIBRA results.