EAGER: Toward the Experimental Detection of Cosmic Relic Neutrinos

渴望：宇宙遗迹中微子的实验检测

• 批准号: 1041588
• 负责人: Joseph Formaggio
• 金额: $ 5.84万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-10-01 至 2011-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1041588&HistoricalAwards=false
• 关键词: EAGER; Toward; Experimental; Detection; Cosmic

The series of measurements made after the initial observation of the Cosmic Microwave Background (CMB) Radiation has helped transform observational cosmology into an extremely predictive science. Many of the parameters of the cosmological concordance model have now been measured and further exploration of these parameters over the next few decades are likely to reveal even more hidden aspects of our universe. Although many of the predictions from cosmology have now been realized, there are others that remain unobserved. The direct detection of the Cosmic Neutrino Background produced from the primordial Big Bang stands as one of the fundamental challenges in both neutrino physics and cosmology. Like their photon counterparts, the existence of relic neutrinos in the cosmos is expected; yet, its direct observation remains elusive. Observation of the cosmic relic neutrinos or, conversely, the absence of such, stands as an important verification of the model.The direct observation of relic neutrinos is an extremely difficult challenge from an experimental perspective. The neutrino temperature, T, is related directly to the CMB temperature, and is expected to be T=1.95 K, or 0.17 meV in energy. Most conventional methods of detecting neutrinos rely on interactions that have some threshold for the energy of the incoming neutrino which is often many orders of magnitude larger than this predicted relic neutrino energy. Fortunately, there exists a good candidate by which such low energy neutrinos can be detected: neutrino capture on radioactive nuclei. The signal of the neutrino capture process is unique: a monoenergetic peak above the endpoint energy of the beta decay energy spectrum. With a detector of sufficient resolution and target mass, detection of the Cosmic Neutrino Background appears, at least in principle, to be possible. This EAGER award is for an exploratory, high-risk, high-payoff effort to build a small novel experiment to test this high precision detection technique.For Broader Impacts, this project addresses a search for the direct detection of the Cosmic Neutrino Background. If successful, it will have significant overlap with particle physics, nuclear physics and astrophysics. The technique envisioned for this measurement has potential ramifications for other disciplines with significant interest in low energy electron metrology.

在对宇宙微波背景（CMB）辐射进行初步观测后进行的一系列测量有助于将观测宇宙学转变为一门极具预测性的科学。宇宙学一致性模型的许多参数现已被测量，未来几十年对这些参数的进一步探索可能会揭示宇宙更多隐藏的方面。尽管宇宙学的许多预测现已实现，但还有一些预测仍未被观测到。直接探测原始大爆炸产生的宇宙中微子背景是中微子物理学和宇宙学的基本挑战之一。与光子对应物一样，宇宙中也存在残余中微子。然而，它的直接观察仍然难以捉摸。宇宙遗迹中微子的观测，或者相反，宇宙遗迹中微子的缺失，是对该模型的重要验证。从实验角度来看，遗迹中微子的直接观测是一个极其困难的挑战。中微子温度 T 与 CMB 温度直接相关，预计 T=1.95 K，或能量为 0.17 meV。大多数检测中微子的传统方法依赖于相互作用，这些相互作用对传入中微子的能量有一定的阈值，该阈值通常比预测的残留中微子能量大许多数量级。幸运的是，存在一种很好的候选方法可以检测这种低能中微子：放射性核上的中微子捕获。中微子捕获过程的信号是独特的：β衰变能谱端点能量上方的单能峰。有了足够分辨率和目标质量的探测器，至少在原则上，探测宇宙中微子背景似乎是可能的。该 EAGER 奖旨在表彰一项探索性、高风险、高回报的努力，旨在建立一个小型新颖实验来测试这种高精度探测技术。为了产生更广泛的影响，该项目致力于寻找直接探测宇宙中微子背景的方法。如果成功，它将与粒子物理学、核物理学和天体物理学产生重大重叠。这种测量设想的技术对其他对低能电子计量有重大兴趣的学科具有潜在的影响。