Study of cosmogenic radionuclides in the COSINE-100 NaI(Tl) detectors
Study of cosmogenic radionuclides in the COSINE-100 NaI(Tl) detectors
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DOI：
10.1016/j.astropartphys.2019.102390
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发表时间：
2020-02-01
影响因子：
3.5
通讯作者：
Yu, G. H.
中科院分区：
文献类型：
--
作者：
de Souza, E. Barbosa;Park, B. J.;Yu, G. H.
COSINE-100是一项直接探测暗物质搜索实验，它使用了一个106千克的8个NaI（Tl）晶体阵列，这些晶体保存在阳阳地下实验室的地下，以避免宇宙射线对放射性同位素的宇宙活化。尽管宇宙活动随着时间的推移而下降，但残余核素的背景辐射率仍然很高。在本文中，我们报告了半衰期小于一年的宇宙成因同位素污染的测量结果，这些污染是基于对晶体在地下部署时其特征能量峰值的时间依赖活动的外推。对于寿命较长的Cd-109 （T-1/2 = 1.27 y）和Na-22 (T-1/2 = 2.6 y)，我们研究了由于几次排放引起的时间相关性和巧合事件。将推断的海平面产量与基于ACTIVIA和MENDL-2模型计算和实验数据的计算结果进行了比较。不同方法的结果有一定的一致性。对于半衰期长达12.3年的H-3，我们评估的活性水平和暴露时间与每个晶体暴露的估计时间一致。(C) 2019 Elsevier B.V.版权所有
COSINE-100 is a direct detection dark matter search experiment that uses a 106 kg array of eight NaI(Tl) crystals that are kept underground at the Yangyang Underground Laboratory to avoid cosmogenic activation of radioisotopes by cosmic rays. Even though the cosmogenic activity is declining with time, there are still significant background rates from the remnant nuclides. In this paper, we report measurements of cosmogenic isotope contaminations with less than one year half-lives that are based on extrapolations of the time dependent activities of their characteristic energy peaks to activity rates at the time the crystals were deployed underground. For longer-lived Cd-109 (T-1/2 = 1.27 y) and Na-22 (T-1/2 = 2.6 y), we investigate time correlations and coincidence events due to several emissions. The inferred sea-level production rates are compared with calculations based on the ACTIVIA and MENDL-2 model calculations and experimental data. The results from different approaches are in reasonable agreement with each other. For H-3, which has a long, 12.3 year half-life, we evaluated the activity levels and the exposure times that are in reasonable agreement with the time period estimated for each crystals exposure. (C) 2019 Elsevier B.V. All rights reserved.