Detection capability of the Migdal effect for argon and xenon nuclei with position-sensitive gaseous detectors
Detection capability of the Migdal effect for argon and xenon nuclei with position-sensitive gaseous detectors
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DOI：
10.1093/ptep/ptaa162
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发表时间：
2020-09
影响因子：
3.5
通讯作者：
K. Nakamura;K. Miuchi;S. Kazama;Y. Shoji;M. Ibe;Wakutaka Nakano
中科院分区：
文献类型：
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作者：
K. Nakamura;K. Miuchi;S. Kazama;Y. Shoji;M. Ibe;Wakutaka Nakano
米格达尔效应由于有可能提高直接暗物质搜索对低质量区域的敏感度而备受关注。尽管它非常重要，但米格达尔效应尚未在实验中被观测到。通过蒙特卡罗模拟研究了一种在中子散射中首次观测米格达尔效应的实际实验方法。在这项研究中，通过中子源研究了潜在的本底率以及米格达尔效应的事件率。研究发现，一个桌面大小的约$(30\mathrm{cm})^3$的位置敏感气体探测器，填充氩气或氙气作为目标气体，能够以足够的速率（每天$O(10^2\sim10^3)$个事件）探测到米格达尔效应的特征信号。一个简单实验装置的模拟结果显示了两个重要的本底源，即本征中子和中子诱发的伽马射线。研究发现氩气的本征中子本底率处于可接受水平，并且未来对实验室伽马射线减少的一些研究将使米格达尔效应的观测成为可能。另一方面，发现氙气的本底比氩气严重得多。在能够观测到氙气情况下的米格达尔效应之前，未来需要在同位素分离以及探测器和实验室伽马射线减少方面开展工作。
The Migdal effect is attracting interest because of the potential to enhance the sensitivities of direct dark matter searches to the low-mass region. In spite of its great importance, the Migdal effect has not been experimentally observed yet. A realistic experimental approach towards the first observation of the Migdal effect in the neutron scattering was studied with Monte Carlo simulations. In this study, the potential background rate was studied together with the event rate of the Migdal effect by a neutron source. It was found that a table-top-sized $\sim (30~\mbox{cm})^3$ position-sensitive gaseous detector filled with argon or xenon target gas can detect characteristic signatures of the Migdal effect with sufficient rates (O($10^2\sim10^3$) events per day). A simulation result of a simple experimental set-up showed two significant background sources, namely the intrinsic neutrons and the neutron-induced gamma-rays. It is found that the intrinsic neutron background rate for the argon gas is at an acceptable level and some future study of the reduction of the gamma-rays from the laboratory would make the observation of the Migdal effect possible. The background for the xenon gas, on the other hand, is found to be much more serious than for the argon gas. Future works on the isotope separation as well as the reduction of the gamma-rays from the detector and laboratory will be needed before the Migdal effect can be observed for the xenon gas case.