CAREER: Particle Astrophysics with High-Resolution Cerenkov Imaging

职业：粒子天体物理学与高分辨率切伦科夫成像

• 批准号: 0642751
• 负责人: Scott Wakely
• 金额: $ 62.48万
• 依托单位: University of Chicago
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-01-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0642751&HistoricalAwards=false
• 关键词: CAREER; Particle; Astrophysics; Resolution; Cerenkov

The nature and origin of cosmic rays remains one of the most elusive questions in high-energy astrophysics. After about a century of analysis, it is not known how and where they are produced, or exactly what mechanisms govern their propagation to earth. A major reason for the impasse lies in the steepness of the cosmic ray energy spectrum, which can be described by a rapidly-falling power-law. To push measurements one decade higher in energy, one requires increasing the instrument size by a factor of ~100. Therefore, relatively small (i.e., affordable) balloon or space-based missions become less practical for measurements above energies much higher than 1014 electron Volts (eV). As the cosmic ray flux decreases, ground-based observatories become the only viable option for providing the needed detector area. However, because the atmosphere prevents primary particles from propagating to the earth's surface, direct observation of these particles is not possible. Instead, ground-based instruments have, by necessity, been forced to make indirect observations of the extensive air showers produced by the interactions of the primaries in the atmosphere. Such observations are relatively low precision. Furthermore, they are hampered by large uncertainties in the interaction models used to interpret the observables. These weaknesses exist in even the most sophisticated air shower detector systems. The research goal of this proposal is to perform, for the first time, high-resolution measurements of cosmic ray composition from a ground-based observatory. This will be achieved by exploiting a new technique, proposed by the PI and others, which provides excellent charge resolution by targeting the direct light produced by the primary particle prior to its first interaction in the atmosphere though a new technology. The requested funding will augment and enable this research effort, ultimately culminating in the construction and operation of a prototype instrument called TRICE, for TRack-Imaging Cerenkov Experiment.The broader impacts of the proposed effort will be felt through the support of young female scientists in a hands-on, experimental small-group setting, through the development of instrumentation applicable to other fields, through the support of a fruitful cross-discipline collaboration with a National Laboratory, and through a dedicated education and outreach program designed to broaden the exposure of under-represented groups to research-based educational material.

宇宙射线的性质和起源仍然是高能天体物理学中最难以捉摸的问题之一。经过大约世纪的分析，人们不知道它们是如何产生的，在哪里产生的，也不知道它们传播到地球的确切机制。 僵局的一个主要原因在于宇宙射线能谱的陡峭性，这可以用快速下降的幂律来描述。为了将测量的能量提高10倍，需要将仪器尺寸增加约100倍。因此，相对较小（即，可负担得起的）气球或基于空间的任务对于远高于1014电子伏特（eV）的能量以上的测量变得不太实际。随着宇宙线通量的减少，地面观测站成为提供所需探测器区域的唯一可行选择。然而，由于大气层阻止初级粒子传播到地球表面，因此不可能直接观察这些粒子。相反，地面仪器不得不对大气中初级粒子相互作用产生的大范围空气簇射进行间接观测。这样的观测精度相对较低。此外，他们是阻碍了大的不确定性，在相互作用模型用来解释观测。即使是最先进的空气簇射探测器系统也存在这些弱点。这项建议的研究目标是首次从地面观测站对宇宙射线的组成进行高分辨率测量。这将通过利用PI和其他人提出的新技术来实现，该技术通过瞄准初级粒子在其在大气中的第一次相互作用之前产生的直射光来提供优异的电荷分辨率。所申请的资金将加强并使这项研究工作得以进行，最终导致为跟踪成像切伦科夫实验建造和运行一个名为TRICE的原型仪器，通过在实践、实验性小组环境中支持年轻女科学家，通过开发适用于其他领域的仪器，通过与国家实验室进行富有成效的跨学科合作，并通过专门的教育和推广计划，旨在扩大代表性不足的群体对基于研究的教育材料的接触。