吨级 76Ge 无中微子双贝塔衰变实验的深度要求
核实验
2013-04-19 v2
摘要
无中微子双贝塔衰变实验有可能确定中微子的 Majorana 或 Dirac 性质，并有助于理解中微子的绝对质量标度和层级。未来基于 76Ge 的搜寻旨在达到 >10^27 年的半衰期灵敏度，以探索反常中微子质量层级。达到此灵敏度需要在衰变 Q 值周围 4 keV 宽的兴趣谱区内实现 <1 count tonne^-1 y^-1 的本底率。我们基于宇宙射线本底率的蒙特卡洛计算，研究了在具有紧凑（铜和铅）屏蔽的吨级实验中达到此本底目标所需的覆盖层厚度。我们发现，鉴于此类计算目前存在较大不确定性，对于具有类似于计划中的 40 kg MAJORANA DEMONSTRATOR 的紧凑屏蔽的吨级实验，需要地下深度 >~5200 mwe 的站点。所需覆盖层高度依赖于所选的屏蔽配置，如果例如采用液态低温剂和水中屏蔽，或主动中子屏蔽，则可显著放宽要求。MAJORANA DEMONSTRATOR 和 GERDA 探测器的运行将有助于减少宇宙射线本底率的不确定性，并将影响未来吨级实验的屏蔽风格和地点选择。2013 年 4 月更新：同行评审过程揭示，其中一个否决拒绝因子（第 12 页描述的 4 倍因子）需要更确凿的确立。迄今为止我们对该参数的重新评估并未对手稿中陈述的数值提供有力支持，我们需要进一步研究以得出可靠的估计。这项进一步的研究将取代本手稿中描述的工作，并且可能会也可能不会得出关于未来吨级 76Ge 无中微子双贝塔衰变实验需要 ~>5200 mwe 要求的相同结论。
引用
@article{arxiv.1109.4154,
title = {Depth Requirements for a Tonne-scale 76Ge Neutrinoless Double-beta Decay Experiment},
author = {The MAJORANA Collaboration and E. Aguayo and F. T. Avignone and H. O. Back and A. S. Barabash and M. Bergevin and F. E. Bertrand and M. Boswell and V. Brudanin and M. Busch and Y-D. Chan and C. D. Christofferson and J. I. Collar and D. C. Combs and R. J. Cooper and J. A. Detwiler and P. J. Doe and Yu. Efremenko and V. Egorov and H. Ejiri and S. R. Elliott and J. Esterline and J. E. Fast and N. Fields and P. Finnerty and F. M. Fraenkle and V. M. Gehman and G. K. Giovanetti and M. P. Green and V. E. Guiseppe and K. Gusey and A. L. Hallin and R. Hazama and R. Henning and A. Hime and E. W. Hoppe and M. Horton and S. Howard and M. A. Howe and R. A. Johnson and K. J. Keeter and M. E. Keillor and C. Keller and J. D. Kephart and M. F. Kidd and A. Knecht and O. Kochetov and S. I. Konovalov and R. T. Kouzes and B. D. LaFerriere and B. H. LaRoque and J. Leon and L. E. Leviner and J. C. Loach and S. MacMullin and M. G. Marino and R. D. Martin and D. -M. Mei and J. H. Merriman and M. L. Miller and L. Mizouni and M. Nomachi and J. L. Orrell and N. R. Overman and D. G. Phillips and A. W. P. Poon and G. Perumpilly and G. Prior and D. C. Radford and K. Rielage and R. G. H. Robertson and M. C. Ronquest and A. G. Schubert and T. Shima and M. Shirchenko and K. J. Snavely and V. Sobolev and D. Steele and J. Strain and K. Thomas and V. Timkin and W. Tornow and I. Vanyushin and R. L. Varner and K. Vetter and K. Vorren and J. F. Wilkerson and B. A. Wolfe and E. Yakushev and A. R. Young and C. -H. Yu and V. Yumatov and C. Zhang},
journal= {arXiv preprint arXiv:1109.4154},
year = {2013}
}
备注
Corresponding author: J. Detwiler ([email protected]), 25 pages, 2 figures