Proposal to Construct a Prototype for TAUWER, a Surface Detector Array for 0.1 - 100 EeV t Neutrino Studies

宇宙射线天文学的目的是进一步了解天体物理现象，揭示宇宙的结构和演化。最高能量带电宇宙射线的来源还没有被清楚地确定。活动星系核（AGN）和遍布宇宙的黑洞提供了可能的来源，分布在所有的膨胀时期。超高能宇宙线（UHECR）与宇宙微波背景辐射发生非弹性碰撞时产生所谓的宇宙成因中微子。 在宇宙距离上，中微子混合产生的三种中微子到达地球时数量大致相等。 各种天体物理模型的质子冲击加速喷流的活动星系核给出了一个范围内的中微子流量和能量分布在0.1-1.0 EeV的范围。由于中微子的截面随着能量的增加而增加，在这个能量范围内的中微子能量太大，无法穿透地球。这个小组提议建造一个小型的原型TAUWER阵列，它将探测τ中微子在地壳中沿沿着向上运动时产生的τ轻子衰变。探测器将位于陡峭的山坡上，沿着接近92度顶角的弦向下观察。该提案将启动TAUWER项目，建设5个站，以研究其在现场的性能，并确定整个系统的改进和简化。 原型检测元件已经过测试，并显示出明确的辨别能力之间的上行和下行粒子。TAUWER是一个成本适中、可快速部署的实验，将提供新的测量能力，并与该领域的其他项目有很好的重叠。 这项为期一年的工作的成功完成将为安装和运行完整的TAUWER奠定基础。该建议借鉴了CMU 2007年春季工程课程的经验，涉及10名本科工程师和社会科学专业的学生。整个项目计划扩大到包括高中学生和教师。整个装置的数据将对其他中微子天体物理学实验起到补充作用。

Cosmic ray astronomy aims to further the understanding of astrophysical phenomena to shed light on the structure and evolution of the Universe. The sources of the highest energy charged cosmic rays have not been clearly identified. Active Galactic Nuclei (AGN) and black holes distributed throughout the cosmos provide possible sources distributed through all epochs of expansion. Ultra High Energy Cosmic Rays (UHECRs) produce so-called cosmogenic neutrinos when they undergo inelastic collisions with the cosmic microwave background radiation. Over cosmic distances, neutrino mixing produces approximately equal populations of the three neutrino species when they get to the earth. Various astrophysical models for proton shock acceleration in the jets of AGN give a range of neutrino flux and energy distributions in the 0.1-1.0 EeV range. Because the neutrino cross section rises with energy, neutrinos in this energy range are too energetic to penetrate the earth. This group proposes to construct a small prototype TAUWER array that will detect the decays of tau-leptons produced by tau-neutrinos moving upward along a chord in the earth's crust. The detector will sit on a steep mountain slope looking down along the chord near a zenith angle of 92 degrees. This proposal will initiate the TAUWER project, building 5 stations to study their performance in the field and to identify improvements and simplifications for the full system. Prototype detection elements have been tested and show clear discrimination capability between upward-coming and downward-moving particles. TAUWER is a modest cost, quickly deployable experiment that will provide new measurement capability and good overlap with other projects in this area. The successful completion of this one-year effort will establish the feasibility of installing and operating a complete TAUWER. This proposal draws on the experience from a spring 2007 engineering course at CMU involving 10 undergraduate engineers and social science students. An expansion to include high school students and teachers is planned for the full project. Data from the full installation will be complementary to other neutrino astrophysics experiments.