Chemical Composition and Energy Spectrum of Cosmic Rays Using the IceCube Neutrino Observatory

宇宙射线不断地轰击大气层，但关于宇宙射线的产生、加速和传播过程的关键信息仍然缺乏。然而，已经开发出候选理论模型，以对在地球上可观测到的宇宙线参数进行可测试的预测。为了测试这些模型，需要在整个能量范围内对宇宙射线的多个元素光谱进行精确的实验测量。利用冰立方中微子天文台(ICNO)，马奎特大学的冰立方小组将利用六年的IceCube数据、新的大型强子对撞机模拟、事件选择的新方法、减少的系统误差、新的软件算法和新的成分敏感参数，为宇宙射线团体提供第一次测量宇宙线能量谱中从“膝盖”到“脚踝”的四个不同质量组的元素光谱。该组织将与更广泛的密尔沃基社区分享他们的研究，以帮助弥合这个美国种族隔离程度最高的城市之一的种族和社会经济鸿沟。在这个奖项下，他们将走进社区，用有趣和互动的“家庭物理”项目激励当地多样化的高中生群体，并将多样化的高中生带回Marquette，通过IceCube大师班让他们接触到“大科学”的工作机会。为了提高高中生对物理的认识，使其成为所有背景的学生的一条强大而可行的职业道路，这项工作将由一个跨文化能力计划来框架，该计划将培训Marquette学生以同情的态度与当地社区互动和联系，提高他们自己的跨文化能力，并在物理系内建立同情文化，以维持女性和未被充分代表的少数群体对物理学的参与。ICNO是目前唯一能够进行这项备受关注的测量的探测器，其中包括整整十年从未测量过四种元素光谱的能量。这将为从银河系到银河系外宇宙射线的整个过渡区域提供一幅新的、连贯的图像。此外，Marquette IceCube小组将模拟和全面优化探测器响应和阵列布局，用于本季度(2018-19年)在南极部分部署的新原型闪烁体阵列，以最大限度地提高其对宇宙线分析的有效性。这一新的阵列旨在缓解威胁当前ICNO表面阵列(IceTop)有效性的积雪和积雪问题。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。

Cosmic rays constantly bombard the atmosphere, yet key information regarding the processes of cosmic ray creation, acceleration, and propagation is lacking. However, candidate theoretical models have been developed to make testable predictions about cosmic ray parameters that are observable at Earth. In order to test these models, precise experimental measurements of multiple elemental spectra of cosmic rays are needed from a single experiment across the full energy range. Using the IceCube Neutrino Observatory (ICNO), the IceCube group at Marquette University will provide the cosmic ray community with the first measurement of the elemental spectra from four distinct mass groups from the 'knee' to the 'ankle' in the cosmic ray energy spectrum using six years of IceCube data, new post-LHC simulations, novel methods for event selection, reduced systematic errors, new software algorithms, and new composition-sensitive parameters. The group will share their research with the broader Milwaukee community to help bridge the racial and socio-economic divide in one of the most highly segregated cities in the United States. Under this award, they will go out into the community to inspire the diverse local high school student population with fun and interactive "household physics" projects and bring diverse high school students back to Marquette to expose them to "big science" job opportunities through an IceCube Master Class. In order to increase awareness among high school students of physics as a strong and viable career path for students from all backgrounds, this work will be framed by an intercultural competency program to train Marquette students to interact and connect with their local community empathetically, increase their own intercultural competency, and to build a culture of compassion within the physics department to sustain the participation of women and underrepresented minorities in physics.The ICNO is the only detector that can presently perform this highly sought measurement that includes an entire decade in energy where four elemental spectra have never been measured. This will provide a new and coherent picture across the entire transition region from galactic to extragalactic cosmic rays. Further, the Marquette IceCube group will simulate and fully optimize the detector response and array layout for a new prototype scintillator array being partially deployed at the South Pole this season (2018-19) to maximize its effectiveness for the cosmic ray analyses. This new array is designed to mitigate the problem of snow drift and accumulation that threatens the effectiveness of the current ICNO surface array (IceTop).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.