EAGER: Direct Detection of MeV-Scale Dark Matter Utilizing Germanium Internal Amplification for the Charge Created by the Ionization of Impurities

多项天文观测证实，宇宙中约85%的物质不是由已知的基本粒子组成的。破译这种所谓的暗物质(DM)的本质对于宇宙学、天体物理学和高能粒子物理都是至关重要的。最令人兴奋的任务之一是寻找超越粒子物理标准模型的新粒子，该模型描述了所有已知的基本粒子以及它们之间的相互作用。该模型的扩展不仅预测了大质量的新粒子，而且还预测了一些质量非常小的新粒子。中微子的一般性质和DM的性质是当前基础物理学中最重要的两个问题。这一热切的奖项将探索一种新的锗(Ge)探测器技术，利用电荷内部放大(GeCIA)来探测由杂质电离产生的电荷载流子，这是一项很有前途的具有实验灵敏度的新技术，用于探测MeV级暗物质。要发现DM，需要新的直接检测策略来探测DM与普通物质之间的非引力相互作用。通过这项探索性工作获得的广泛资源将使下一代探测器能够以符合成本效益的方式满足灵敏度要求。开发的技术将立即应用于几个实验，包括DM计划和美国和世界其他地方的低能中微子计划。发展下一代多样化工人的工作同样重要，也是计划活动的核心。一名女性博士后将全面参与该项目，成为开发GeCIA探测器的专业人员。此外，三名博士生也将参与该项目。GeCIA将采取分阶段的方法，在桑福德地下研究设施(SURF)建立一个实验，直接搜索质量范围从0.1 MeV到1GeV的DM。GeCIA-0是一个探索性项目，它将创新质量为300克的GeCIA探测器，以展示用于p型平面几何的技术。他们将用非晶态Ge(a-Ge)接触技术制造一种平面探测器，该技术已成功地用于在美国大学用自主生长的晶体制造探测器。这笔资金将支持该小组(1)通过蒙特卡洛模拟优化此类平面探测器的设计；(2)使用a-Ge接触技术制造平面探测器；(3)使用合适的电子读出系统证明GeCIA技术；以及(4)校准具有光学和低能量辐射源的探测器。该奖项反映了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。

Multiple astronomical observations have established that about 85% of the matter in the universe is not made of known elementary particles. Deciphering the nature of this so-called Dark Matter (DM) is of fundamental importance to cosmology, astrophysics, and high-energy particle physics. One of the most exciting quests is the search for new particles beyond the Standard Model of Particle Physics, which describes all the known elementary particles and the interactions between them. Extensions of the model predict not only new particles with large masses but also some with very small masses. The general properties of neutrinos and the nature of DM are currently two of the most important questions in fundamental physics. This EAGER award will explore a new germanium (Ge) detector technology utilizing Charge Internal Amplification (GeCIA) for the charge carriers created by the ionization of impurities, which is a promising new technology with experimental sensitivity for detecting MeV-scale dark matter.Novel direct-detection strategies to probe non-gravitational interactions between DM and ordinary matter are needed to discover DM. The broad resources gained through this exploratory work will enable the development of next generation detectors that meet sensitivity requirements in a cost-effective manner. The techniques developed will have immediate application to several experiments, including the DM program and low energy neutrino program in the U.S. and elsewhere in the world. Equally important and central to the planned activities is its work to develop the next generation of diverse workers. One female postdoc will fully work on the project and become expertise in developing GeCIA detectors. In addition, three PhD students will also work on the project.GeCIA will adopt a phased approach to build an experiment at Sanford Underground Research Facility (SURF) to directly search for DM with a mass range from 0.1 MeV to 1 GeV. GeCIA-0 is an exploratory project that will innovate GeCIA detectors at a mass of 300 grams to demonstrate the technology for a p-type planar geometry. They will fabricate a planar detector with amorphous Ge (a-Ge) contact technology, which has been successfully used to fabricate detectors at USD with home-grown crystals. This funding will support the group to (1) optimize the design of such a planar detector with Monte Carlo simulation; (2) fabricate a planar detector with a-Ge contact technology; (3) prove GeCIA technology with appropriate electronic read-out system; and (4) calibrate detectors with optical and low energy radiative sources.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.