Collaborative Research: 2016-2019 Development of the Askaryan Radio Array Ultra-High Energy Neutrino Detector at the South Pole

超高能中微子是一种独特的天体物理信使，它与中间物质的相互作用很弱，因此可以用来探测遥远的宇宙。这些超高能中微子的一小部分但在理论上可以观察到的通量，预计将由高能“宇宙射线”带电粒子和宇宙微波背景光子之间的相互作用产生，因为宇宙射线在宇宙中传播。观测这些宇宙起源的中微子将使物理学家能够在超出标准模型的能量下开始研究物理学。覆盖在南极洲地理南极的大量射电透明冰层是利用射电切伦科夫“阿斯基恩效应”探测这些高能中微子的开创性工作的所在地。阿斯基恩效应描述了超高能中微子穿越致密极地冰层产生可观察到的无线电波的过程。位于南极空间站的阿斯基恩无线电阵列(ARA)旨在利用这一现象首先探测并最终研究这些超高能中微子。这项奖励提供资金，用于在现有的三个站中再部署两个ARA站，并继续进行观测。该奖项将支持包括本科生在内的学生参与南极的现场活动。它还将支持外联工作，包括与QuarkNet的活动。ARA旨在分阶段实施。在最初阶段，ARA项目部署了一个试验台和三个全站，它们使用了为共处的冰立方中微子天文台设计和建造的设备。有了这一奖项，该项目将再部署两个站，并继续与所有站一起进行观测，以演示技术，积累关于南极冰盖上层无线电频率特性的知识，并为未来可部署的冰内站开发可靠的硬件和软件。

Ultra-high-energy neutrinos are unique astrophysical messengers that interact weakly with intervening matter and can therefore be used to probe the distant universe. A small but theoretically observable flux of these ultra-high-energy neutrinos is expected to be produced by the interaction between high-energy "cosmic ray" charged particles and cosmic microwave background photons as the cosmic rays travel through the Universe. Observing these cosmogenic neutrinos would allow physicists to begin to study physics at energies beyond the standard models. The large volume of radio transparent ice covering the geographic South Pole in Antarctica has hosted several pioneering efforts to detect these high energies neutrinos using a radio Cherenkov "Askaryan effect." The Askaryan effect describes the process by which ultra-high-energy neutrinos traversing the dense polar ice generate observable radio waves. The Askaryan Radio Array (ARA), located at the South Pole Station, was designed to exploit this phenomenon to first detect and ultimately study these ultra-high-energy neutrinos. This award provides funding to deploy two more ARA stations to the existing suite of three stations, and to continue observations. The award will support the involvement of students, including undergraduate students, who will be engaged in on-site activities at the South Pole. It will also support outreach efforts including activities with QuarkNet.ARA is designed to be implemented in phases. During the initial phase the ARA project deployed a testbed and three full stations that used equipment designed and built for the co-located IceCube Neutrino Observatory. With this award the project will deploy two more stations and continue observations with all stations to demonstrate the technology, accumulate knowledge about radio frequency properties of the upper layers of the ice sheet at South Pole, and develop reliable hardware and software for deployable in-ice stations in the future.