Precise Q Values for Ultra-Low Energy and Highly Forbidden Beta Decays Using Penning Trap Mass Spectrometry

使用潘宁阱质谱法获得超低能量和高度禁止的 Beta 衰变的精确 Q 值

• 批准号: 2111302
• 负责人: Matthew Redshaw
• 金额: $ 27万
• 依托单位: Central Michigan University
• 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=2111302&HistoricalAwards=false
• 关键词: Precise; Values; Ultra; Low; Energy

The study of extreme phenomena in the physical sciences has often provided new discoveries and insights. In this project the PI will investigate one extreme limit of radioactive decays: beta-decays that occur with very low energy. These decays are interesting because they can be used in experiments to determine the mass of the neutrino (the light, neutral particle that is also emitted in beta-decay) and because they require the development of a more detailed theoretical description of the effect of atomic electrons on the nuclear decay process. To date, only one ultra-low energy beta decay has been observed (that of Indium-115). There are many other potential candidates, but the atomic masses of the parent and daughter nuclei are not known precisely enough to determine whether the proposed decay can actually occur. In this project the PI will perform precision atomic mass measurements of low energy beta decay systems using Penning trap mass spectrometry. The technique involves confining ions with magnetic and electric fields and then measuring the ion cyclotron frequency in the trap; from which atomic mass can be determined. Experiments will take place at Michigan State University and at Central Michigan University (CMU), providing training in experimental nuclear physics techniques for undergraduate and Ph.D. students at CMU.Weak decay processes such as nuclear beta-decay have provided significant contributions to our understanding of nuclear, atomic and particle physics. They continue to be of interest to aid our understanding of astrophysical processes, nuclear structure, fundamental symmetries, and properties of the neutrino. Very rare weak decay processes, such as highly forbidden, ultra-low Q value, and double-beta decays are important for investigating the particle nature and mass scale of the neutrino, modelling and understanding the background in very low count rate experiments, and for testing theoretical descriptions of nuclear beta-decay. In the proposed work, the PI will perform precise measurements of Q values for potential ultra-low energy beta-decay systems using LEBIT at the Facility for Rare Isotope Beams (FRIB). The decays of interest occur between the ground state of the parent nuclide and an excited state in the daughter with an energy of 1 keV. The proposed measurements will help to identify isotopes that are potential candidates for ultra-low Q value decays. These isotopes could be used in future neutrino mass experiments and will also be important for enabling meaningful tests of nuclear theory for these extreme decays where atomic interference effects are expected to play a significant role. The work will be performed by Ph.D. and undergraduateThis 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.

对物理科学中极端现象的研究经常提供新的发现和见解。在这个项目中，PI将研究放射性衰变的一个极端极限：以非常低的能量发生的β衰变。这些衰变是有趣的，因为它们可以在实验中用来确定中微子（轻的中性粒子，也在β衰变中发射）的质量，因为它们需要对原子电子对核衰变过程的影响进行更详细的理论描述。到目前为止，只有一个超低能量β衰变被观察到（铟-115）。还有许多其他可能的候选者，但是母核和子核的原子质量还不足以精确地确定所提出的衰变是否真的会发生。在这个项目中，PI将使用潘宁阱质谱法对低能β衰变系统进行精确的原子质量测量。该技术包括用磁场和电场限制离子，然后测量阱中的离子回旋频率;从中可以确定原子质量。实验将在密歇根州立大学和中密歇根大学（CMU）进行，为本科生和博士生提供实验核物理技术培训。弱衰变过程，如核β衰变，为我们理解核、原子和粒子物理学做出了重大贡献。它们仍然对帮助我们理解天体物理过程、核结构、基本对称性和中微子性质感兴趣。非常罕见的弱衰变过程，如高度禁戒、超低Q值和双β衰变，对于研究中微子的粒子性质和质量尺度、建模和理解极低计数率实验的背景以及检验核β衰变的理论描述都很重要。在拟议的工作中，PI将在稀有同位素束设施（FRIB）使用LEBIT对潜在超低能β衰变系统的Q值进行精确测量。感兴趣的衰变发生在母体核素的基态和子体中的激发态之间，能量为1 keV。拟议的测量将有助于确定超低Q值衰变的潜在候选同位素。这些同位素可以用于未来的中微子质量实验，也将是重要的，使核理论的有意义的测试，这些极端的衰变，原子干涉效应预计将发挥重要作用。这项工作将由博士执行。该奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估的支持。

项目成果

Identification of a potential ultralow- Q -value electron-capture decay branch in Se75 via a precise Penning trap measurement of the mass of As75

通过对 As75 质量进行精确潘宁陷阱测量，识别 Se75 中潜在的超低 Q 值电子捕获衰变分支

• DOI: 10.1103/physrevc.106.065503
• 发表时间: 2022
• 期刊: Physical Review C
• 影响因子: 3.1
• 作者: Horana Gamage, M.;Bhandari, R.;Bollen, G.;Gamage, N. D.;Hamaker, A.;Puentes, D.;Redshaw, M.;Ringle, R.;Schwarz, S.;Sumithrarachchi, C. S.
• 通讯作者: Sumithrarachchi, C. S.

Precise Q value determinations for forbidden and low energy $$\beta $$-decays using Penning trap mass spectrometry

使用潘宁陷阱质谱法精确确定禁能和低能 $$eta $$ 衰变的 Q 值

• DOI: 10.1140/epja/s10050-023-00925-9
• 发表时间: 2023
• 期刊: The European Physical Journal A
• 作者: Redshaw, Matthew

Updated evaluation of potential ultralow Q -value β -decay candidates

对潜在超低 Q 值 β 衰变候选者的更新评估

• DOI: 10.1103/physrevc.107.015504
• 发表时间: 2023
• 期刊: Physical Review C
• 影响因子: 3.1
• 作者: Keblbeck, D. K.;Bhandari, R.;Gamage, N. D.;Horana Gamage, M.;Leach, K. G.;Mougeot, X.;Redshaw, M.
• 通讯作者: Redshaw, M.