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.

在最初观测到宇宙微波背景辐射（CMB）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。宇宙学和谐模型的许多参数现在已经被测量，在未来几十年内对这些参数的进一步探索可能会揭示我们宇宙的更多隐藏方面。虽然宇宙学的许多预测现在已经实现，但还有一些尚未观测到。直接探测宇宙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。与光子中微子一样，宇宙中也存在残余中微子，这是人们所期待的;然而，对它的直接观测仍然是难以捉摸的。宇宙残余中微子的观测，或者相反，宇宙残余中微子的不存在，是对该模型的重要验证。从实验的角度来看，直接观测宇宙残余中微子是一个极其困难的挑战。中微子的温度T与CMB的温度直接相关，预计T=1.95 K，或0.17 meV的能量。大多数探测中微子的传统方法都依赖于相互作用，这些相互作用对入射中微子的能量有一定的阈值，通常比预测的残余中微子能量大很多个数量级。幸运的是，有一个很好的候选者可以检测到这样的低能中微子：中微子在放射性核上的捕获。中微子捕获过程的信号是独特的：在β衰变能谱的端点能量之上的单能峰。有了足够的分辨率和目标质量的探测器，宇宙中微子背景的探测至少在原则上是可能的。这个EAGER奖是一个探索性的，高风险的，高回报的努力，建立一个小型的新实验，以测试这种高精度的探测技术。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。设想这种测量的技术具有潜在的影响，在低能量电子计量学的显着兴趣的其他学科。