标题： DAMA是否在放射性氩气的海洋中沐浴？ 显示英文标题

标题： Is DAMA Bathing in a Sea of Radioactive Argon?

摘要： 一个假设被提出以解释长期存在的DAMA/LIBRA谜题。 引入到DAMA/LIBRA屏蔽中的是一种名义上高纯度的氮气净化气体，根据该假设，这种气体中含有氩杂质。 氩气通过净化气体管道的泄漏或商业供应的瓶装氮气进入氮气净化气体，通过探测器外壳中的材料扩散，然后直接与DAMA/LIBRA探测器接触。 这些氩杂质可以在两种情况下导致调制的2.8 keV背景。 情景1）：这些杂质包括同位素37Ar，它通过电子捕获衰变，发出2.8 keV的X射线。 这些衰变在DAMA/LIBRA中表现为单点、单能事件，并由于大气和地表中中子通量的变化而产生年度调制，这又导致了由反应$^{40}\textrm{Ca}(\textrm{n,}\alpha)^{37}\textrm{Ar}$和$^{36}\textrm{Ar}(\textrm{n,}\gamma)^{37}\textrm{Ar}$产生的37Ar产量的季节性变化。 情景2）：氡气也存在于DAMA/LIBRA的净化气体中，其季节性调制速率低于当前DAMA/LIBRA的限制。 当氡气或其短寿命子体衰变时，所产生的β射线、γ射线和轫致辐射会使围绕NaI(Tl)探测器的铜外壳中的稳定40Ar电离，从而产生特征性的2.8 keV X射线。 由周围洞穴中的氡诱导中子或γ射线通量也可能导致调制背景，由于铜外壳中40Ar的存在，在低能区会增强这种小的调制背景。 通过分析净化气体以及在电离辐射激发下对DAMA/LIBRA铜外壳进行蒙特卡罗和实验室研究，可以轻松测试这两种情景。 显示英文摘要

摘要： A hypothesis is proposed to explain the long-standing DAMA/LIBRA puzzle. Introduced into the DAMA/LIBRA shielding is a purge gas of nominally high-purity nitrogen, which under this hypothesis contains argon impurities. Argon is introduced into the nitrogen purge gas either through leaks in the purge gas plumbing, or through commercially-supplied bottled nitrogen, diffuses through materials in the detector housings, and then comes in direct contact with the DAMA/LIBRA detectors. These argon impurities can then lead to a modulating 2.8 keV background under two scenarios. Scenario 1): These impurities include the isotope 37Ar, which decays by electron capture, emitting a 2.8 keV x-ray. These decays appear as single-site, monoenergetic events in DAMA/LIBRA, and produce an annual modulation due to the variation of neutron flux in the atmosphere and at the Earth's surface, which in turn leads to a seasonal variation in 37Ar production from the reactions $^{40}\textrm{Ca}(\textrm{n,}\alpha)^{37}\textrm{Ar}$ and $^{36}\textrm{Ar}(\textrm{n,}\gamma)^{37}\textrm{Ar}$. Scenario 2): Radon is also in the DAMA/LIBRA purge gas, modulating seasonally at a rate below the current DAMA/LIBRA limits. When radon or its short-lived daughters decay, the resulting beta, gamma, and bremsstrahlung radiation cause stable 40Ar to be ionized within the copper housings surrounding the NaI(Tl) detectors, resulting in characteristic 2.8 keV x-rays. Modulating backgrounds might also result from radon-induced neutron or gamma-ray flux from the surrounding cavern, leading to a small modulating background enhanced at low energy by the presence of 40Ar within the copper housings. These two scenarios are straightforward to test through assay of the purge gas as well as Monte Carlo and laboratory study of the DAMA/LIBRA copper housings when excited by ionizing radiation.