Air showers in IceCube

冰立方中的空气阵雨：对冰立方和冰顶（ANT-0602679）数据的分析。从外太空到达地球的基本粒子是来自高能天体物理源的信号，如爆炸的恒星和大质量黑洞。被称为宇宙射线的高能粒子被冲击波和其他湍流过程加速，这些湍流过程与大量引力能的释放有关，这也导致了可见光、x射线和其他电磁波频谱波长的壮观表现。这项研究的重点是对数据的分析，这将有助于更好地理解产生最高能量宇宙粒子的特定类型的来源和机制。冰立方中微子观测站目前正在美国国家科学基金会的阿蒙森-斯科特南极站建设，它将利用南极冰川清澈、深厚的冰作为探测弱相互作用中微子的大目标，这种中微子也有望从某些宇宙射线源中发现，但迄今为止还没有发现。中微子观测站建成后，将由4800个光学模块组成，监测超过一立方公里的冰，以捕捉中微子相互作用的闪光特征。冰立方中中微子的主要特征将是中微子穿透地球后向上移动的事件。冰立方表面有一组探测器，这些探测器可以部分阻止冰立方上方大气中宇宙射线相互作用产生的穿透μ子的下降背景。这个表面阵列被称为“冰顶”，将由160个冰罐组成，每个冰罐都配有两个标准的冰立方光学模块，用于探测大气中高能宇宙射线相互作用产生的二次粒子阵雨。这项拨款支持的分析将集中在由表面阵列和深层探测器同时探测到的宇宙射线事件上。深信号与地表信号的比值可以用来测量重宇宙射线（如铁核）与轻宇宙射线（如质子）在一个能量区域的相对比例，而用气球或航天器携带的探测器无法直接观测到这个能量区域。特别是，我们将寻找从我们银河系内部的源到银河系外更高能量源的转变的特征。我们还将分析无线电冰切伦科夫实验同时采集的数据，寻找与冰顶的巧合，以此将我们的研究扩展到更高的能量。截至2006年，冰立方在冰面上有9串60个探测器，有32个冰顶储罐在运行。它已经是同类中最大的探测器，随着建设的进行，分析将开始。在这项资助的过程中，我们将巩固和改进我们的推广工作，使之成为一个连贯的项目。我们将首先创建一个关于科学和技术的网页，并与冰立方的照片和视频收集相连接。然后，我们将正式扩大目前针对K-12学生和公众的不定期讲座计划。

Air showers in IceCube: Analysis of data from IceCube and IceTop (ANT-0602679)Elementary particles reaching Earth from outer space are signals from energetic astrophysical sources such as exploding stars and massive black holes. The high-energy particles, called cosmic-rays, are accelerated by shock waves and other turbulent processes associated with the release of massive amounts of gravitational energy, which also lead to spectacular displays in visible light, X-rays, and other wavelengths of the electromagnetic spectrum. The focus of this research is on analysis of data that will lead to a better understanding of the specific types of sources and mechanisms that are responsible for the highest energy cosmic particles.The IceCube Neutrino Observatory, now under construction at the National Science Foundation's Amundsen-Scott South-Pole Station, will use the clear, deep ice of the Antarctic glacier as a large target for detecting weakly interacting neutrinos, which are also expected from certain cosmic-ray sources, but which have so far not been found. The neutrino observatory, when complete, will consist of 4800 optical modules monitoring more than a cubic kilometer of ice for flashes of light characteristic of neutrino interactions. The primary signature for a neutrino in IceCube will be an upward-moving event from a neutrino that has penetrated the Earth. IceCube includes an array of detectors on the surface that serve as a partial veto for the down-going background of penetrating muons created by cosmic-ray interactions in the atmosphere above IceCube. The surface array, called IceTop, will consist of 160 tanks of ice, each instrumented with two standard IceCube optical modules, to detect showers of secondary particles generated by interactions of high-energy cosmic rays in the atmosphere. The analysis supported by this grant will focus on cosmic-ray events detected in coincidence by both the surface array and the deep detectors. The ratio of deep signal to surface signal can be used to measure the relative fraction of heavy cosmic rays (e.g. nuclei of iron) to light cosmic rays (e.g. protons) in an energy region not accessible to direct observation with detectors carried above the atmosphere on balloons or spacecraft. In particular we will look for a characteristic signature of a transition from sources inside our Milky Way Galaxy to extra-Galactic sources at higher energy. We will also analyze data taken simultaneously by the Radio Ice Cherenkov Experiment, looking for coincidences with IceTop as a way of extending our research to still higher energy. As of 2006, IceCube has 9 strings of 60 detectors each in the ice, and there are 32 IceTop tanks in operation. It is already the largest detector of its kind, and analysis will start as construction proceeds.During the course of this grant we will consolidate and improve our outreach efforts into a coherent program We will start by creating a web page about the science and techniques, with connections to the IceCube photo and video collection. Then we will formalize and extend our current program of occasional lectures for K-12 students and the public.