论文标题
使用纯化锌搜索$^{64} $ Zn的双$β$ -DECAY模式
Search for double $β$-decay modes of $^{64}$Zn using purified zinc
论文作者
论文摘要
超纯原材料的生产是确保在罕见事件搜索中确保背景水平的关键步骤。在这项工作中，我们建立了一种创新技术，可以生产高纯度（99.999％）颗粒状锌。我们通过测量实验室Nazionali del Gran Sasso的高纯锗检测器的纯化锌的内部污染来证明精炼程序的有效性。在几个MBQ/kg的水平上测量了宇宙激活的核素的总活性，并且天然存在的放射性核素的限制设置为小于MBQ/kg。锌样品的极佳放射性可放射性使我们能够搜索$^{64} $ Zn的正电子捕获和中微子的双电子捕获，并在其半衰期上设置当前最严格的下限，$ t_ {1/2} {1/2}^{ c.i.）和$ t_ {1/2}^{0 \ nu2 \ varepsilon}> 2.6 \ times 10^{21} \ text {yr} $（90％c.i.）。
The production of ultra-pure raw material is a crucial step to ensure the required background level in rare event searches. In this work, we establish an innovative technique developed to produce high-purity (99.999%) granular zinc. We demonstrate the effectiveness of the refining procedure by measuring the internal contaminations of the purified zinc with a high-purity germanium detector at the Laboratori Nazionali del Gran Sasso. The total activity of cosmogenic activated nuclides is measured at the level of a few mBq/kg, as well as limits on naturally occurring radionuclides are set to less than mBq/kg. The excellent radiopurity of the zinc sample allows us to search for electron capture with positron emission and neutrinoless double electron capture of $^{64}$Zn, setting the currently most stringent lower limits on their half-lives, $T_{1/2}^{\varepsilonβ^+} > 2.7 \times 10^{21}\text{yr}$ (90% C.I.), and $T_{1/2}^{0\nu2\varepsilon}> 2.6 \times 10^{21}\text{yr}$ (90% C.I.), respectively.
