Student researcher selected for 'beam time' at Stanford accelerator lab

LAWRENCE — A University of Kansas graduate student who searches for some of the most elemental and elusive particles in the universe has been selected to participate in a prestigious federal research program.

Steven Prohira, a fourth-year doctoral student from Denver, does experimental research in high-energy physics. He is one of just 52 graduate students nationwide selected to participate in the U.S. Department of Energy’s 2017 Office of Science Graduate Student Research Program. That means Prohira will get to travel to Stanford University in spring 2018 for a rare opportunity to conduct experiments at the SLAC National Accelerator Laboratory.

“This lab measurement is one I’ve wanted to do since I joined the program,” Prohira said. “So to get to go out there and do this in the spring is really thrilling.”

Dave Besson, KU professor of physics & astronomy, serves as Prohira’s adviser. He said that it’s difficult even for faculty-level researchers to obtain “beam time” at the Stanford accelerator.

“It’s a hot commodity,” Besson said. “For faculty, you can make a request, but the chances are less than 50 percent. For Steven as a graduate student to be awarded beam time is a big deal.”

Prohira plans to use his lab time to test a technique that could, eventually, help researchers search for neutrinos in Antarctic ice. Neutrinos are subatomic particles that physicists believe can help unlock some mysteries of how the universe functions. High-energy neutrinos originate off-Earth, created through the nuclear reactions at the hearts of stars, for example.

“They’re very interesting to study because they don’t fit into current theories of physics very well,” Prohira said.

“A neutrino, because it doesn’t interact with matter, flies straight,” Prohira said. “So if you detect it on Earth, that points straight back to where it came from. That tells us about its source, where they’re generated, and that can help us pin down what they’re about.”

But they’re hard to find, he said: A neutrino might appear in a square kilometer of land once per century, which means Prohira and other researchers must perfect their techniques for finding neutrinos. At Stanford, he’ll fire an electron beam at a polyethylene target, which has similar properties to Antarctic ice, and use radio waves to try to detect the entire shower of particles produced by the collision. The electron beam will act as a proxy for a very high-energy neutrino.

“It’s basically a problem of scale,” Prohira said. “The challenge is to cover a huge area with as little apparatus as possible.”

The experiment builds on research Prohira has done in collaboration with Besson, who has himself ventured to the South Pole in the ongoing effort to detect the tiny particles. Besson is a pioneer of radio-based neutrino physics, specifically in Antarctica.

“He’s a good guy, and he’ll do well,” Besson said of Prohira. “He’s industrious. He had an interesting idea for a project. It’s a testament to his initiative, his work ethic and his industriousness.”

The Graduate Student Research Program was established to support graduate students; it provides awards to allow such students to spend up to 12 consecutive months at a DOE national laboratory conducting graduate thesis research. The award provides support for travel to and from the laboratory as well as a monthly stipend of up to $3,000 for general living expenses while at the host DOE laboratory.

The Department of Physics & Astronomy is part of the College of Liberal Arts & Sciences. The College is the heart of KU, educating the most students, producing the most research and collaborating with nearly every entity at KU. The College is home to more than 50 departments, programs and centers, as well as the School of the Arts, School of Literatures, Languages & Cultures, and School of Public Affairs & Administration.