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U. testing cosmic ray detectors

Gear at Little Mountain will be moved to desert

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LITTLE MOUNTAIN — Over the years, many fans of the night sky have trekked to the top of Emigration Canyon, somewhat shielded from Salt Lake City's lights, to peer through a huge variety of instruments. But they never had equipment like this.

The newcomer is a portable cosmic ray detector. University of Utah physicists set up the two container vehicles, field generator and motor home more than a week ago.

Peering from the end of one of the vehicles, the detector's big clover-leaf mirrors have been scanning the heavens for flashes of light, which show where cosmic rays blast through the atmosphere.

For now, its main purpose is not to measure these mysterious particles from space, although that would be a welcome by-product. The scientists' immediate goal is to work out potential glitches before they drive the portable lab to the Millard County desert.

There, possibly in February, it will begin scientific observations that may pave the way to eventually setting up 10 clusters of 40 detectors each.

"This is more of a technical shakedown than actually characterizing the atmosphere," said Charles C.H. Jui, assistant professor and an expert in cosmic ray physics.

"The main objective's to make sure everything works nearby." When the researchers have confidence in its ability, they will drive it 200 miles to a remote site in Millard County, where it can begin categorizing the atmosphere.

"I think we've got most of the problems sorted out," Jui said during an interview Wednesday night at Little Mountain. If all questions are answered on Little Mountain, the vehicles were to return to the U. soon, probably Monday.

The Delta region was earmarked years ago for international cosmic ray observatories that would detect particles as they hit the ground. But the U.'s project uses mirrors to track sparks as the rays strike the atmosphere, releasing "air showers" of sparks of ultraviolet light.

By studying the flashes, researchers can figure out where the cosmic ray entered the atmosphere, the direction it was traveling and how much energy it released. Eventually they hope to learn more about the strange processes that create cosmic rays.

If the U.'s observatory can work in tandem with ground collectors, the amount of information will multiply. But even if those projects don't come through, a fleet of portable stations could advance knowledge of cosmic rays.

"We've been struggling real hard to make this detector work and be mobile, be cheap," said John Matthews, program manager for the U.'s High Resolution Fly's Eye Observatory at Dugway Proving Ground. "What we'd like to do is take our detectors that we've been operating out at Dugway . . . and start working our way down into Millard County."

"We're going to try and make sure than any one event is seen by two or three detectors," Jui said. That will allow scientists to triangulate and get its exact distance and energy. Rob Riehle, a graduate research assistant at the U., has been working on the project's hardware, getting the generator and computers working. "One of the things we needed to calculate was show much fuel we were going through," he said, speaking of the generator.

On the first night, the scientists struggled to get the generator running properly.

"It's been dang cold," Matthews said. "While they were struggling for the first handful of hours it was mighty cold up here."

Another problem is that a microwave antenna, which could not be of use to anyone but the researchers, was stolen from one of the vans.

Manning the office through the week were Andreas Zech and Stefan Karg, volunteers from Rutgers, the state university of New Jersey. Both from Germany, the men are graduate students doing the grunt work of recording cosmic ray data.

"We take night shifts, every night, for like 10 hours or something," Zech said. "And we're sitting in this office and we're taking data, opening the door (the roll-up cover over the detector) and everything, and making the detector run."

"One day it was pretty nice," Karg said. On that night the fog cleared enough that they could record some images.

Soon the detector is to lumber south to Millard county, where it can begin observing the condition of the atmosphere, making baseline studies that will be used in the search for cosmic rays.

For now, inside the warm office vehicle, computer screens showed flickering lights picked up during a recent run. Most were the strobes of aircraft lights or glints from headlights on the nearby highway. Some were electronic noise inside the instruments.

But occasionally, a straight line flashed across the segment of computer screen, indicating either a cosmic ray shower or a muon from space.


E-MAIL: bau@desnews.com