史蒂芬-普罗希拉 物理学家

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史蒂芬-普罗希拉
物理学家｜2022级
挑战传统理论，设计新的工具来检测超高能量的亚原子粒子，这些粒子可能为我们宇宙中长期存在的奥秘提供线索。


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标题
物理学家
工作单位
堪萨斯大学物理学和天文学系
工作地点
堪萨斯州，劳伦斯
年龄
获奖时35岁
重点领域
物理学、天体物理学和天文学
网站
prohira.com
堪萨斯大学。Steven Prohira
雷达回波望远镜
2022年10月12日发布
关于史蒂文的工作
史蒂文-普罗希拉是一位物理学家，他通过在理论、工程和实验设计这三个不同领域罕见地结合专业知识，推动了对宇宙射线和超高能中微子的研究。普罗希拉在他的建议中借鉴了这种知识的广度，提出了一种新的方法来探测被称为超高能中微子的臭名昭著的亚原子粒子。宇宙中微子是高能量、高温空间事件的残留物，如恒星内的核聚变反应。它们是电中性的，几乎没有质量，与物质的互动非常弱。由于它们可以穿过行星和恒星等大质量物体而不损失能量，因此它们是来自太阳系以外的重要信使，而且非常难以观察。

即使作为研究生，普罗希拉也在大规模中微子探测实验中发挥了重要作用。在一个案例中，他用一个校准和测量系统支持了南极洲冲动瞬变天线（ANITA）的研究。高能中微子在通过密集的质量时，有时会与原子发生碰撞。这种相互作用会产生带电粒子和电磁辐射的级联，或称淋浴，可由高度敏感的无线电接收器观察到。在资金有限的情况下，Prohira和合作者设计并建造了HiCal-2，一个廉价的、现成的无线电频率发射器和气球有效载荷。HiCal-2帮助ANITA团队从环境背景辐射中分辨出潜在的中微子信号，完善并进一步验证了更大（更昂贵）的主系统的经验测量。他现在是超高能观测有效载荷（PUEO）团队的成员，这是与NASA合作的该项目的延伸。最近，普罗希拉发明了一种潜在的改变游戏规则的技术，用于探测能量范围超过迄今已测量的中微子。雷达回波望远镜（RET）使用现有的雷达技术来跟踪中微子在冰中运动产生的电离云上反射的无线电波的 "回波"。这项技术建立在先前提出的通过雷达探测大气层中的宇宙射线的基础上，但该方法被证明是不成功的，因为很难将极弱的信号从背景噪声中区分出来。Prohira及其同事最近在SLAC国家加速器中心的实验室环境中展示了对密集材料中带电粒子阵的雷达探测。他们现在正在建立一个原型，以便在现场进行实验。如果成功的话，RET将使研究人员能够扫描更大的区域，以了解中微子与极地冰的相互作用，而同时也大大减少了目前阻碍该领域的高成本和设备复杂性的负担。普罗希拉是一位具有独特才能和大胆想法的早期职业科学家，他完全有能力帮助改变我们对宇宙中长期存在的奥秘的认识。

个人简历
史蒂芬-普罗希拉在冈萨加大学获得学士学位（2009年），在堪萨斯大学获得硕士学位（2016年）和博士学位（2018年）。目前，他是堪萨斯大学物理和天文学系的助理教授。在这之前，他是俄亥俄州立大学宇宙学和天体粒子物理中心（CCAPP）的总统博士后学者和研究员（2018-2022）。他的研究发表在《宇宙学和天体粒子物理学杂志》和《物理评论快报》等刊物上。




Steven Prohira
Physicist | Class of 2022
Challenging conventional theories and engineering new tools to detect ultra-high energy sub-atomic particles that could hold clues to long-held mysteries of our universe.


Portrait of Steven Prohira
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Title
Physicist
Affiliation
Department of Physics and Astronomy, University of Kansas
Location
Lawrence, Kansas
Age
35 at time of award
Area of Focus
Physics, Astrophysics and Astronomy
Website
prohira.com
University of Kansas: Steven Prohira
Radar Echo Telescope
Published October 12, 2022
ABOUT STEVEN’S WORK
Steven Prohira is a physicist advancing the study of cosmic rays and ultra-high energy neutrinos through a rare combination of expertise in three distinct areas: theory, engineering, and experimental design. Prohira draws on this breadth of knowledge in his proposal for a novel method for detecting the notoriously elusive sub-atomic particles known as ultra-high energy neutrinos. Cosmic neutrinos are remnants of high energy, high temperature space events, such as nuclear fusion reactions within stars. They are electrically neutral, nearly massless, and interact very weakly with matter. Since they can pass through massive objects like planets and stars without losing energy, they are important messengers from outside of our solar system and very difficult to observe.

Even as a graduate student, Prohira played important roles in large-scale neutrino detection experiments. In one case, he supported the Antarctic Impulsive Transient Antenna (ANITA) study with a calibration and measurement system. High-energy neutrinos will sometimes collide with atoms when passing through dense masses. This interaction produces a cascade, or shower, of charged particles and electromagnetic radiation that can be observed by a highly sensitive radio receiver. With limited funds at their disposal, Prohira and collaborators designed and built HiCal-2, an inexpensive, off-the-shelf radio frequency transmitter and balloon payload. HiCal-2 helped the ANITA team distinguish potential neutrino signals from ambient background radiation, refining and further validating the empirical measurements of the larger (and more expensive) primary system. He is now a member of the team for Payload for Ultrahigh Energy Observations (PUEO), an extension of this project with NASA. More recently, Prohira has invented a potentially game-changing technique for detecting neutrinos in an energy range beyond what has been measured to date. The Radar Echo Telescope (RET) uses existing radar technology to track the “echo” of radio waves reflected off ionization clouds produced by neutrinos moving through ice. This technique builds on a prior proposal for detecting cosmic rays via radar in the atmosphere, but the method proved unsuccessful due to the difficulty of distinguishing the extremely weak signal from background noise. Prohira and colleagues recently demonstrated radar detection of charged particle showers in a dense material in a lab-based setting at the SLAC National Accelerator Center. They are now building a prototype for experimentation in the field. If successful, the RET would enable researchers to scan much larger areas for neutrino interactions with polar ice than current methods allow, while also significantly reducing the burdens of high cost and equipment complexity that currently frustrate the field. An early career scientist with a unique combination of talents and bold ideas, Prohira is well-positioned to help transform what we know about long-held mysteries of our universe.

BIOGRAPHY
Steven Prohira earned a BA (2009) from Gonzaga University and an MS (2016) and a PhD (2018) from the University of Kansas. Currently, he is an assistant professor in the Department of Physics and Astronomy at the University of Kansas. Prior to this appointment, he was a President’s Postdoctoral Scholar and Fellow at the Center for Cosmology and AstroParticle Physics (CCAPP) at the Ohio State University (2018–2022). His research has appeared in such journals as the Journal of Cosmology and Astroparticle Physics and Physical Review Letters, among other publications.