MRI: Development of the ARIANNA High Energy Neutrino Telescope Instrument

阿里安娜超高能中微子计划的主要目的是每年观测约40个由GZK机制产生的宇宙源中微子，并有足够的精度来确定它们的能谱和相互作用性质。GZK中微子的能谱为了解宇宙线的产生机制和源分布提供了重要的信息。此外，弥散宇宙中微子信号角分布的统计显著测量可以用来推断能量超过大型强子对撞机探测到的能量的相互作用截面。虽然GZK机制的物理原理很简单(河外UHE质子与宇宙微波背景光子相撞，产生最终衰变为中微子的介子)，但回答宇宙射线如何被加速到非常高的能量特别困难，因为我们银河系的磁场使宇宙射线弯曲，而GZK机制将宇宙射线的射程限制在大约100兆弧秒。现在，成功的高能中微子项目利用了南极洲丰富而透明的冰，留下了很长的遗产。特别是，Arianna依靠探测中微子在密集介质中相互作用后产生的射电脉冲，利用了美国南极计划行动的中心麦克默多站附近的罗斯冰架的几个显著特性：(1)冰对无线电频率的电磁辐射是惊人的透明，(2)大陆架下方的水-冰边界就像一面镜子，可以反射来自任何下行方向的中微子的无线电信号，以及(3)在感兴趣的频段内，背景噪声水平相当适中。它靠近麦克默多车站，为后勤支持提供了许多合适的选择，而Arianna的可扩展架构使其能够遵循科学。该合同允许该项目开发阿里安娜自治站所需的数据采集电子设备。在以高精度、低功耗电子设备操作六角形阵列方面获得的经验将满足未来扩展阵列所需的性能要求。该项目将继续通过将研究生和本科教育与技术和仪器开发、实地观察和科学分析相结合，为培养下一代科学家作出重大贡献。

The primary purpose of the ARIANNA Ultra-High Energy (UHE) Neutrino project is to observe ~40 cosmogenic neutrinos per year originated by the GZK mechanism with sufficient precision to determine their energy spectrum and interaction properties. The energy spectrum of GZK neutrinos provides important insight on the production mechanism and source distribution of the cosmic rays. In addition, a statistically significant measurement of the angular distribution of the diffuse cosmogenic neutrino signal can be used to infer the interaction cross-section at energies beyond those probed by Large Hadron Collider. While the physics of the GZK mechanism is straightforward (extragalactic UHE protons collide with cosmic microwave background photons, producing pions that eventually decay to neutrinos), answering how the cosmic rays were accelerated to very high energies is especially difficult because cosmic rays are bent by magnetic fields in our Galaxy, and their range is limited by the GZK mechanism to ~100 megaparcecs. There is now a long legacy of successful high-energy neutrino programs that utilize the abundant and transparent ice of Antarctica. In particular, ARIANNA relies on the detection of radio pulses generated after neutrino interactions in dense media by the Askaryan effect, capitalizing on several remarkable properties of the Ross Ice Shelf near McMurdo Station, the hub of U.S. Antarctic Program operations: (1) the ice is impressively transparent to electromagnetic radiation at radio frequencies, (2) the water-ice boundary below the shelf behaves like a good mirror to reflect radio signals from neutrinos in any downward direction, and (3) background noise levels were quite modest in the frequency band of interest. Its close proximity to McMurdo Station provides a number of suitable options for logistical support, and ARIANNA's scalable architecture allows it to follow the science. This award allows the project to develop the data acquisition electronics required by the ARIANNA autonomous stations. Experience gained in operating the hexagonal array with precision, low power electronics would frame the performance requirements needed to expand the array in the future. The project will continue contributing significantly to the training of next generation of scientists by integrating graduate and undergraduate education with technology and instrumentation development, field observations, and scientific analysis.