SuperNEMO Commissioning and Sensitivity Demonstration

SuperNEMO 调试和灵敏度演示

• 批准号: ST/K002856/1
• 负责人: David Waters
• 金额: $ 118.1万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2013
• 资助国家: 英国
• 起止时间: 2013 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FK002856%2F1
• 关键词: SuperNEMO; Commissioning; Sensitivity; Demonstration

Neutrinos are the most abundant matter particle in the universe, and yet our knowledge of them is still lacking in fundamental respects. We do not know whether neutrinos and anti-neutrinos are really distinct particles, or just different versions of the same underlying particle, which is possible since they do not carry any charge. In recent decades neutrino oscillation experiments have shed considerable light on the flavour structure of neutrinos, and in particular how neutrinos may turn from one flavour into another due totheir tiny mass differences. However, despite knowing rather precisely these mass differences, we still do not know what the absolute mass scale of theneutrino is. One of the highest priorities in particle physics today is to elucidate some of these mysteries surrounding the neutrino. This maygive us further insight into such fundamental questions as the nature ofphysics at the extremely high energies associated with Grand Unification,and the source of the matter-antimatter asymmetry which we observe in theuniverse today.Beta decay is a familiar radioactive process whereby a parent nucleusdecays into a daughter nucleus with the emission of an electron andan (unseen) anti-neutrino. In certain nuclei beta decay is forbidden but,very rarely, two simultaneous beta decays may occur. The distinctivesignature of two electrons being emitted has been observed in severalisotopes. We are searching for a distinct form of double-beta decayin which no neutrinos are emitted alongside the electrons, resulting inthe electrons carrying away the full energy of the associated nucleardecay. This "neutrinoless" process can only occur if neutrinos and anti-neutrinos are the same fundamental particle. Moreover, by measuring the rate of such decays we can effectively measure the absolute mass of the neutrino.In order to search for neutrinoless double-beta decay with greatersensitivity then ever before, we have built what is essentially the largest Geiger counter in the world. This so-called "tracker" for the SuperNEMO experiment records ionisation left by the electrons from the double-beta decay and allows us to visualise the tracks that they leavein the detector. UK groups have been building this tracking detectorfor the last 3 years, based on extensive R&D that took place before that.The next phase for SuperNEMO is to take the UK-built tracker to anunderground laboratory located under the Alps between France and Italyin order to shield the experiment from cosmic rays. There, we will marry the tracker with the other components of the detector that are being assembled by colleagues in France, Russia, the Czech Republic andthe US. Extensive work will be required to carefully assemble thefirst module of SuperNEMO, called the "Demonstrator Module", such thatit works as expected and that no radioactive contamination is allowed to enter the detector. Even trace contamination, far below the level of radioactivityin ordinary materials, could completely swamp the very rare processes thatwe are searching for.By the end of this project, the SuperNEMO Demonstrator Module will beup and running and launching into an exciting physics program to tryto address some of the fundamental questions outlined above.

中微子是宇宙中最丰富的物质粒子，但我们对它们的认识仍然缺乏基本方面。我们不知道中微子和反中微子是否真的是不同的粒子，或者只是同一个底层粒子的不同版本，这是可能的，因为它们不带任何电荷。近几十年来，中微子振荡实验对中微子的味道结构有了相当大的了解，特别是中微子如何由于它们微小的质量差异而从一种味道变成另一种味道。然而，尽管我们已经相当精确地知道了这些质量差异，我们仍然不知道中微子的绝对质量尺度是多少。当今粒子物理学的首要任务之一是阐明中微子周围的一些谜团。这可能会让我们更深入地了解一些基本问题，比如在与大统一有关的极高能量下的物理学性质，以及我们今天在宇宙中观察到的物质-反物质不对称性的来源。β衰变是一种常见的放射性过程，即母核衰变为子核，并发射出一个电子和（看不见的）反中微子。在某些核中，β衰变是被禁止的，但很少同时发生两个β衰变。在几种同位素中已经观察到发射出两个电子的独特特征。我们正在寻找一种独特的双β衰变形式，在这种形式中，没有中微子与电子一起发射，导致电子带走了相关核衰变的全部能量。这种“无中微子”的过程只有在中微子和反中微子是相同的基本粒子时才能发生。此外，通过测量这种衰变的速率，我们可以有效地测量中微子的绝对质量。为了以前所未有的灵敏度寻找无中微子双β衰变，我们建造了世界上最大的盖革计数器。SuperNEMO实验中所谓的“跟踪器”记录了双β衰变中电子留下的电离，并使我们能够可视化它们离开探测器的轨道。在此之前进行了大量的研发工作，英国的研究小组在过去的3年里一直在建造这种跟踪探测器。SuperNEMO的下一个阶段是将英国建造的跟踪器带到位于法国和意大利之间阿尔卑斯山下的地下实验室，以屏蔽宇宙射线的实验。在那里，我们将把跟踪器和探测器的其他部件结合起来，这些部件是由法国、俄罗斯、捷克共和国和美国的同事组装的。将需要大量的工作来仔细组装SuperNEMO的第一个模块，称为“演示模块”，这样它就可以按预期工作，并且不允许任何放射性污染进入探测器。即使是远低于普通材料中放射性水平的微量污染，也可能完全淹没我们正在寻找的非常罕见的过程。在这个项目结束时，SuperNEMO演示模块将启动并运行，并启动一个令人兴奋的物理程序，试图解决上面概述的一些基本问题。

项目成果

Final results on $${}^\mathbf{82 }{\hbox {Se}}$$82Se double beta decay to the ground state of $${}^\mathbf{82 }{\hbox {Kr}}$$82Kr from the NEMO-3 experiment

$${}^mathbf{82 }{hbox {Se}}$$82Se 双贝塔衰变到 $${}^mathbf{82 }{hbox {Kr}}$$82 基态的最终结果

• DOI: 10.1140/epjc/s10052-018-6295-x
• 发表时间: 2018
• 期刊: The European Physical Journal C
• 作者: Arnold, R.;Augier, C.;Barabash, A. S.;Basharina-Freshville, A.;Blondel, S.;Blot, S.;Bongrand, M.;Boursette, D.;Brudanin, V.;Busto, J.
• 通讯作者: Busto, J.

Construction and commissioning of the SuperNEMO detector tracker

SuperNEMO探测器跟踪器的构建和调试

• DOI: 10.1016/j.nima.2015.11.083
• 发表时间: 2016
• 期刊: Accelerators, Spectrometers, Detectors and Associated Equipment
• 作者: Cascella M

Development of methods for the preparation of radiopure Se-82 sources for the SuperNEMO neutrinoless double-beta decay experiment

开发用于 SuperNEMO 无中微子双 β 衰变实验的放射性纯 Se-82 源的制备方法

• DOI: 10.1515/ract-2019-3129
• 发表时间: 2019
• 期刊: Radiochimica acta
• 影响因子: 1.8
• 作者: A.~V.~Rakhimov, A.~S.~Barabash

Results of the search for neutrinoless double- ß decay in Mo 100 with the NEMO-3 experiment

利用 NEMO-3 实验寻找 Mo 100 中无中微子双衰变的结果

• DOI: 10.1103/physrevd.92.072011
• 发表时间: 2015
• 期刊: Physical Review D
• 影响因子: 5
• 作者: Arnold R

Search for the double-beta decay of $^{82}$Se to the excited states of $^{82}$Kr with NEMO-3

使用 NEMO-3 搜索 $^{82}$Se 到 $^{82}$Kr 激发态的双贝塔衰变

• DOI: 10.1016/j.nuclphysa.2020.121701
• 发表时间: 2021
• 期刊: Nuclear physics
• 作者: R.Arnolda, C.Augierb