A COHERENT Next Step: Precision Measurement of CENNS Using PPC Germanium Detectors at the SNS

在所有已知的基本粒子中，中微子之所以脱颖而出，是因为它们与其他形式的物质相互作用的可能性很小，因此在探测过程中遇到了困难。通常涉及大型(吨或多吨)探测器。相干中微子-核弹性散射(CEnNS)是40多年前预言的一种中微子相互作用机制，直到最近才被相干合作测量到。通过CEnNS探测到中微子的概率比任何其他已知的中微子与物质相互作用的模式都要大得多，但产生的信号很微妙，很难分离出来。只有通过辐射检测的最新进展，才有可能访问这些信号。CEnNS开启了使用小型手持设备进行中微子探测的可能性，产生了一些有趣的技术应用。这一奖项将促进在Oak Ridge国家实验室建造最先进的锗探测器，以资助建造最先进的锗探测器，从而促进在Oak Ridge国家实验室内研究这种有希望的新型中微子相互作用。这些设备将以前所未有的精度测量CEnns，约束躲避的中微子的许多仍未知的性质，并有助于完善粒子相互作用的基本理论。这些装置开发的几个方面将适用于它们在核不扩散应用中的计划使用，在核不扩散应用中，CEnns可被用来监测核反应堆，防止武器级材料被转用。计划中的CEnNS能谱测量将在以下最佳条件下进行：信号与背景比、大的统计数据、对全范围反冲能量的敏感性以及探测器对核反冲的详细反应。后者将通过过去、正在和计划中测量CEnNS诱导的核反冲的锗猝灭因子来实现，一直到亚keV能量。这一新的CEnNS测量预期的适度不确定性将允许与标准模型(SM)预测进行非常精确的比较。这一比较将显著提高目前粒子物理活跃研究领域的实验灵敏度：例如，研究中微子的电磁性质，通过粒子物理标准模型的扩展预测其非标准耦合，测试暗物质模型，以及提高对第四个不育中微子的灵敏度，仅举几例。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Of all known elementary particles, neutrinos stand out for the difficulty involved in their detection, a result of their tiny probability of interaction with other forms of matter. Large (ton or multi-ton) detectors are typically involved. Coherent Neutrino-Nucleus Elastic Scattering (CEnNS) is a mechanism of neutrino interaction predicted more than four decades ago, and only recently measured by the COHERENT collaboration. The probability of neutrino detection via CEnNS is much larger than for any other known mode of neutrino interaction with matter, but the signals generated are subtle and hard to isolate. It is only through recent advances in radiation detection that it has become possible to access these signals. CEnNS opens up the possibility of employing small, handheld devices for neutrino detection, generating some interesting technological applications. This award will facilitate a next step in the investigation of this promising new type of neutrino interaction within COHERENT, funding the construction of state-of-the-art germanium detectors to be used at the Spallation Neutron Source at the Oak Ridge National Laboratory. The devices will measure CEnNS with an unprecedented precision, constraining the many still unknown properties of the evasive neutrino, and contributing to a refinement of the underlaying theories of particle interactions. Several aspects of the development of these devices will apply to their planned use in nuclear non-proliferation applications, where CEnNS can be exploited to monitor nuclear reactors against diversion of weapons-grade material. The planned measurement of the CEnNS energy spectrum will be performed in optimal conditions of signal-to-background ratio, large statistics, sensitivity to the full range of recoil energies, and detailed knowledge of detector response to nuclear recoils. The latter will be achieved through past, ongoing, and planned measurements of the germanium quenching factor for CEnNS-induced nuclear recoils, down to sub-keV energies. The modest uncertainties expected from this new CEnNS measurement will allow a very precise comparison to Standard Model (SM) predictions. A significant improvement of the present experimental sensitivity in a number of active areas of research in particle physics will result from this comparison: for instance, the study of electromagnetic properties of neutrinos, their non-standard couplings predicted by extensions of the Standard Model of particle physics, tests of dark matter models, and an improved sensitivity to a fourth sterile neutrino, to name a few.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.