Old tech provides new way to study cosmic rays

Scientists at the University of Utah are using old technology to find a new way to explore high-energy cosmic rays.

John Belz, a research associate professor of physics at the U., is using an old analog TV transmitter donated by KUTV and other equipment to detect cosmic rays as they hit the Earth.

The transmitter — part of the W.M. Keck Bistatic Radar Observatory — will emit a sounding wave, and several receiver antennas placed 25 miles away will look for radar scattering as the rays cascade through the atmosphere.

The observatory will be next to the Telescope Array project in Delta, allowing Belz and other researchers to determine how accurate their radar readings are in comparison to the array's sensors that are spread across more than 300 square miles of Bureau of Land Management land.

Radar observation, Belz said, will allow scientists to scan a much larger area at a much lower cost than the ground-based detectors currently used.

"We're looking at the same events as the Telescope Array, but using a different technology," Belz said. "We can cover a lot of ground, unlike radiation detectors, which are expensive and can only be put on a finite amount of ground."

Ultra high-energy cosmic rays are the "highest-energy radiation in the universe," Belz said.

"The mechanisms to form the rays are among the most violent processes in the universe," Belz said. "Where are they coming from, what is the chemical composition?"

Utah's West Desert makes a particularly good place to study cosmic rays, which hit the atmosphere and cause a cascade reaction of particles that eventually hit the Earth. The north-south running mountains in Western Utah and Nevada break up the winds, allowing the particle showers to fall with fewer interruptions. Also, the near radio silence throughout the area allows for more accurate readings.

The idea took root several years ago when Helio Takai, a physicist at Brookhaven National Laboratory on Long Island, was working with high school students to look for coincidences between a cosmic ray hitting the area and radar readings. Some U. professors invited Takai to come to Utah to do the same project. They attempted to build their own transmitter, but in 2009, "when the analog TV stations switched to digital, we were able to get the transmitter we needed," Takai said.

With funding from the National Science Foundation and the W.M. Keck Foundation, the project started and saw "first light" on Memorial Day Weekend.

The transmitter will take a sample once per second, and ultra high-energy cosmic rays hit the area about once a week.

smcfarland@sltrib.com

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