Telescope array in Delta expands to analyze low-energy cosmic rays

Cosmic rays » Sensors will allow scientists to gather more data on low-energy cosmic rays.

An intricate dance of helicopters, physicists and cosmic ray sensors played out in Utah’s west desert Thursday as the University of Utah expanded its telescope array in Delta.

The new sensors, called scintillator surface detectors, are part of the Telescope Array Low Energy Extension project, or TALE, which will place 35 sensors in an additional 30 square miles of land owned by the Bureau of Land Management. The only way to deliver the sensors was by air as vehicles are not allowed on the federally protected land.

Since 2007, the array, which exists on 300 square miles, allows physicists to analyze ultra high energy cosmic rays that come from outside of the Milky Way Galaxy.

The new extension will allow physicists to analyze lower-energy cosmic rays that originate from within the galaxy. Ultra-high energy rays hit 1 square kilometer once per century while the lower-energy rays hit every few minutes.

"The rate is about 1 million times higher for TALE than for the highest energies," said Gordon Thomson, U. professor of physics. The array is a joint project among the U. and universities in Japan, Korea, Russia and Belgium.

The lower-energy rays will allow physicists to better understand the composition of the nearby rays in hopes of better understanding the high-energy ones.

"When it’s dark and you lose your keys, you look under the lamppost where the light is," Thomson said. "In a sense, we’re looking under the lamppost. This is an energy range where we can answer questions in a much more simple way than the ultra-high energy ways. It will provide a lot of data as we go. We’re just expanding our horizons."

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, so the typical westerly winds can’t kick up much dust, allowing the particle showers to fall with fewer interruptions, Thomson said.