Measurement of scintillation and ionization yield with high-pressure gaseous mixtures of Xe and TMA for improved neutrinoless double beta decay and dark matter searches
Measurement of scintillation and ionization yield with high-pressure gaseous mixtures of Xe and TMA for improved neutrinoless double beta decay and dark matter searches
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使用 Xe 和 TMA 的高压气态混合物测量闪烁和电离产率，以改进无中微子双 β 衰变和暗物质搜索
DOI：
10.1088/1748-0221/11/03/c03041
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发表时间：
2015
影响因子：
1.3
通讯作者：
J. Renner
中科院分区：
文献类型：
--
作者：
Y. Nakajima;A. Goldshmidt;H. Matis;T. Miller;D. Nygren;C. Oliveira;J. Renner
气态氙（Xe）时间投影室（TPC）是一种用于无中微子双β衰变和弱相互作用大质量粒子（WIMP）暗物质探测的有吸引力的探测技术。虽然与液态氙探测器相比，它的密度较低，但在径迹探测能力和更好的能量分辨率方面具有内在优势。气态氙的性能可通过三甲胺（TMA）等分子添加剂进一步提高，预计三甲胺可（1）冷却电离电子，（2）通过彭宁转移将氙的激发能转化为三甲胺的电离，以及（3）在更易探测的波长（300纳米）产生闪烁和电致发光光。为了测试使用三甲胺提高性能的可行性，我们首次对氙和三甲胺的气体混合物的彭宁转移效率和荧光转移效率进行了直接测量。虽然我们观察到彭宁转移效率高达约35%，但我们发现三甲胺对初级闪烁光有强烈的抑制作用。我们还发现，氙和三甲胺混合物的初级闪烁光可以通过从氙到三甲胺约3%的荧光转移来很好地表征，并且由于三甲胺的自猝灭会有进一步的抑制。没有发现三甲胺离子复合产生闪烁光的证据。这种对闪烁光的强烈抑制使得暗物质探测极具挑战性，而改进无中微子双β衰变探测的可能性仍然存在。这项工作是在NEXT合作项目的背景下进行的。
The gaseous Xenon(Xe) time projection chamber (TPC) is an attractive detector technique for neutrinoless double beta decay and WIMP dark matter searches. While it is less dense compared to Liquid Xe detectors, it has intrinsic advantages in tracking capability and better energy resolution. The performance of gaseous Xe can be further improved by molecular additives such as trimethylamine(TMA), which is expected to (1) cool down the ionization electrons, (2) convert Xe excitation energy to TMA ionizations through Penning transfer, and (3) produce scintillation and electroluminescence light in a more easily detectable wavelength (300 nm). In order to test the feasibility of the performance improvements with TMA, we made the first direct measurement of Penning and fluorescence transfer efficiency with gaseous mixtures of Xe and TMA. While we observed a Penning transfer efficiency up to ∼35%, we found strong suppression of primary scintillation light with TMA. We also found that the primary scintillation light with Xe and TMA mixture can be well characterized by ∼3% fluorescence transfer from Xe to TMA, with further suppression due to TMA self-quenching. No evidence of the scintillation light produced by recombination of TMA ions was found. This strong suppression of scintillation light makes dark matter searches quite challenging, while the possibility of improved neutrinoless double beta decay searches remains open. This work has been carried out within the context of the NEXT collaboration.