nEXO: a Search for Neutrino-less Double Beta Decay with a Tonne-Scale Enriched Xenon Time Projection Chamber

nEXO：利用吨级浓缩氙时间投影室寻找无中微子双贝塔衰变

• 批准号: 2111213
• 负责人: Andrea Pocar
• 金额: $ 72.5万
• 依托单位: University of Massachusetts Amherst
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2111213&HistoricalAwards=false
• 关键词: nEXO; Search; Neutrino; less; Double

A fundamental question in contemporary science is why the Universe contains more matter than anti-matter. This award supports investigations into one possible explanation for the origin of this imbalance through the study of whether the mass of the lightest fundamental massive particle in Nature, the neutrino, is matter or anti-matter, or perhaps is a combination of both at the same time. A neutrino could simultaneously be both, enabling a nuclear process known as neutrino-less double-beta decay in which a nucleus transforms into another by emitting two electrons and no neutrinos. If observed, this decay would indicate that neutrinos and anti-neutrinos are the same particle. The NSF/DOE Nuclear Science Advisory Committee (NSAC) has recommended a US-led, ton-scale neutrino-less double-beta decay experiment as the top priority for the field. The UMass group, along with scientists from universities and national laboratories in the US, Canada, China, France, Germany, Russia, South Africa, South Korea, and Switzerland have proposed the nEXO experiment to search for neutrino-less double-beta decay of xenon-136. Using five tons of isotopically enriched liquid xenon nEXO will achieve a 100-fold improved sensitivity with respect to today’s experiments. The work at UMass focuses on R&D for the design and optimization of nEXO and the extraction of science from the dataset previously recorded by EXO-200, the nEXO predecessor. The nEXO detector will be built around a Time Projection Chamber (TPC) that allows scientists to identify and suppress background signals which can mimic neutrino-less double-beta decay. The detector measures the position and energy of every ionizing event inside its volume. Combined with a detector design that minimizes the radioactivity in its constituents, the feeble neutrino-less double beta decay signal can emerge above environmental noise.The UMass group will work on the development of key elements for the nEXO detector. The PI is the Level-2 scientist for the nEXO TPC Support (TPCS) team and the UMass group will develop cryogenics, refrigeration infrastructure, Liquid Xenon storage capabilities, xenon handling, and purification systems. The PI will also study the long-term stability of VUV-sensitive Silicon PhotoMultipliers (SiPMs) for nEXO using a cryostat where xenon can be condensed into a test cell. The group will develop a calibration source for nEXO which can be injected into the xenon flow stream. And the group will also search for sub-dominant neutrino-less double beta decay of xenon-136 and xenon-134 in the previously recorded EXO-200 dataset. The activities covered by this award will train students in STEM fields, open doors for students from diverse backgrounds, and develop technologies that align with strategic sectors of our economy such as data science, artificial intelligence, nuclear medicine, and national security. The Amherst Center for Fundamental Interactions (ACFI) contributes to promoting the physics related to this proposal to the broader physics community.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

当代科学中的一个基本问题是为什么宇宙包含的物质比反物质更多。该奖项通过研究对这种不平衡的起源的一种可能解释的研究，该研究是通过研究自然界中最轻的基本质量粒子的质量是物质还是反物质，或者可能同时是两者的组合。神经元可以简单地是既可以是神经元双β衰减的核过程，在该核过程中，核过程通过发出两个电子和无神经元来转化为另一种核。如果观察到，这种衰变将表明神经元和抗中性菌是同一粒子。 NSF/DOE核科学咨询委员会（NSAC）建议采用美国领导的无量神经元的双β衰减实验，作为该领域的首要任务。 UMASS集团与来自美国，加拿大，中国，法国，德国，俄罗斯，南非，韩国和瑞士的大学和国家实验室的科学家一起提出了Nexo实验，以寻找Xenon-136的无神经元双β衰减。相对于当今的实验，使用五吨同位素富集的液体氙神经Nexo将提高100倍的灵敏度。 UMass的工作重点介绍了Nexo的设计和优化的研发，以及从Nexo前任Exo-200录制的数据集中提取科学的研究。 Nexo检测器将围绕时间投影室（TPC）建造，该时间投影室（TPC）允许科学家识别和抑制可以模仿无神经元双β衰减的背景信号。检测器测量其体积内每个电离事件的位置和能量。结合一个探测器设计，可以最大程度地减少其构成的放射性，而微弱的无中微子双β衰减信号可能会超过环境噪声。 PI是Nexo TPC支持（TPC）团队的2级科学家，UMass组将开发低温，制冷基础设施，液体Xenon存储能力，XENON处理和纯化系统。 PI还将使用低温恒温器研究NEXO的VUV敏感硅光层流（SIPMS）的长期稳定性，在该冷冻仪中可以将氙气凝结到测试细胞中。该组将开发Nexo的校准源，该校准源可以注入XENON流动流中。该小组还将在先前记录的EXO-200数据集中搜索Xenon-136和Xenon-134的无神经元双β衰减。该奖项涵盖的活动将在STEM领域培训学生，为来自不同背景的学生开门，并开发与我们经济的战略部门相吻合的技术，例如数据科学，人工智能，核医学和国家安全。阿默斯特基本互动中心（ACFI）有助于促进与更广泛的物理社区相关的物理学。该奖项反映了NSF的法定任务，并通过使用该基金会的智力优点和更广泛的影响来评估NSF的法定任务。

项目成果

Kiloton-scale xenon detectors for neutrinoless double beta decay and other new physics searches

• DOI: 10.1103/physrevd.104.112007
• 发表时间: 2021-10
• 作者: A. Avasthi;T. Bowyer;C. Bray;T. Brunner;N. Catarineu;E. Church;R. Guenette;S. Haselschwardt;J. Hayes;M. Heffner;S. Hertel;P. Humble;A. Jamil;S. Kim;R. Lang;K. Leach;B. Lenardo;W. Lippincott;A. Marino;D. McKinsey;E. Miller;D. Moore;B. Mong;B. Monreal;M. Monzani;I. Olcina;J. Orrell;S. Pang;A. Pocar;P. Rowson;R. Saldanha;S. Sangiorgio;C. Stanford;A. Visser

The EXO-200 detector, part II: auxiliary systems

EXO-200 探测器，第二部分：辅助系统

• DOI: 10.1088/1748-0221/17/02/p02015
• 发表时间: 2022
• 期刊: Journal of Instrumentation
• 影响因子: 1.3
• 作者: Ackerman, N.;Albert, J.;Auger, M.;Auty, D.J.;Badhrees, I.;Barbeau, P.S.;Bartoszek, L.;Baussan, E.;Belov, V.;Benitez-Medina, C.
• 通讯作者: Benitez-Medina, C.

Search for MeV electron recoils from dark matter in EXO-200

在 EXO-200 中搜索来自暗物质的 MeV 电子反冲

• DOI: 10.1103/physrevd.107.012007
• 发表时间: 2023
• 期刊: Physical Review D
• 影响因子: 5
• 作者: Al Kharusi, S.;Anton, G.;Badhrees, I.;Barbeau, P. S.;Beck, D.;Belov, V.;Bhatta, T.;Breidenbach, M.;Brunner, T.;Cao, G. F.
• 通讯作者: Cao, G. F.

Performance of novel VUV-sensitive Silicon Photo-Multipliers for nEXO

• DOI: 10.1140/epjc/s10052-022-11072-8
• 发表时间: 2022-09
• 期刊: The European Physical Journal C
• 作者: G. Gallina;Y. Guan;F. Retière;G. Cao;A. Bolotnikov;I. Kotov;S. Rescia;A. Soma;T. Tsang;L. Darroch;T. Brunner;J. Bolster;J. Cohen;T. P. Franco;W. Gillis;H. P. Smalley;S. Thibado;A. Pocar;A. Bhat;A. Jamil;D. Moore;G. Adhikari;S. A. Kharusi;E. Angelico;I. Arnquist;P. Arsenault;I. Badhrees;J. Bane;V. Belov;E. Bernard;T. Bhatta;P. Breur;J. Brodsky;E. Brown;E. Caden;L. Cao;C. Chambers;B. Chana;S. Charlebois;D. Chernyak;M. Chiu;B. Cleveland;R. Collister;M.Cvitan;J. Dalmasson;T. Daniels;K. Deslandes;R. DeVoe;M. Vacri;Y. Ding;M. Dolinski;A. Dragone;J. Echevers;B. Eckert;M. Elbeltagi;L. Fabris;W. Fairbank;J. Farine;Y. Fu;D. Gallacher;P. Gautam;G. Giacomini;C. Gingras;D. Goeldi;R. Gornea;G. Gratta;C. Hardy;S. Hedges;M. Heffner;E. Hein;J. Holt;E. Hoppe;J. H¨oßl;A. House;W. Hunt;A. Iverson;X. Jiang;A. Karelin;L. Kaufman;R. Kr¨ucken;A. Kuchenkov;K. S. Kumar;A. Larson;K. Leach;B. Lenardo;D. Leonard;G.Lessard;G. Li;S. Li;Z. Li;C. Licciardi;R. Lindsay;R. Maclellan;M. Mahtab;S. Majidi;C. Malbrunot;P. Margetak;P. Martel-Dion;L. Martin;J. Masbou;N. Massacret;K. McMichael;B. Mong;K. Murray;J. Nattress;C. Natzke;X. Ngwadla;J. Ondze;A. Odian;J. Orrell;G. S. Ortega;C. Overman;S. Parent;A. Perna;A. Piepke;N. Pletskova;J. Pratte;V. Radeka;E. Raguzin;G. J. Ramonnye;T.Rao;H. Rasiwala;K. Raymond;B. Rebeiro;G. Richardson;J. Ringuette;V. Riot;T. Rossignol;P. Rowson;L. Rudolph;R. Saldanha;S. Sangiorgio;X. Shang;F. Spadoni;V. Stekhanov;X. Sun;A. Tidball;T. Totev;S. Triambak;R. Tsang;O. A.Tyuka;F. Vachon;M. Vidal;S. Viel;G. Visser;M. Wagenpfeil;M. Walent;K. Wamba;Q. Wang;W. Wang;Y. Wang;M. Watts;W. Wei;L. Wen;U. Wichoski;S. Wilde;M. Worcester;W. Wu;X. Wu;L. Xie;W. Yan;H. Yang;L. Yang;O. Zeldovich;J. Zhao;T. Ziegler;Rohde Schwarz

A backing detector for order-keV neutrons

keV级中子的后备探测器

• DOI: 10.1016/j.nima.2022.166981
• 发表时间: 2022
• 期刊: Detectors and Associated Equipment
• 作者: Biekert, A.;Chaplinsky, L.;Fink, C.W.;Garcia-Sciveres, M.;Gillis, W.C.;Guo, W.;Hertel, S.A.;Heuermann, G.;Li, X.;Lin, J.
• 通讯作者: Lin, J.