The detector array, named Auger (“oh-jay”) North, will be a network of tanks, each 12 feet in diameter and filled with purified water. The tanks will sit approximately one and a half miles apart, waiting to capture evidence of high-energy cosmic rays.
The purpose of the project is to collect data on the highest energy particles now known to science. These particles are detected on earth in the form of cosmic rays.
“We want to find out where they [the rays] come from and why they have such enormous energy,” said Auger Project Manager Paul Mantsch.
Scientists believe these high-energy rays come from outside the Milky Way, but do not know how or why this high-energy matter is created.
Cosmic “rays” begin as a single high-energy particle that crashes into the Earth’s atmosphere, colliding with nitrogen molecules and creating a cascade of enormously energized particles.
Auger scientists hope this cascade of secondary particles showering the Earth’s surface will give them clues to the extra-galactic origins of the original primary particle.
Low-energy cosmic rays were discovered at the beginning of the century. Scientists think they are generated inside the Milky Way.
Second Observatory an Improvement
The project is massive, not only for the amount of earth covered but also for human cooperation. It requires the participation of communities in five Colorado counties, where residents must agree to have 44,000 tanks dotting their ranches and towns for the next 20 years.
The observatory completed its South Auger detector in 2008, near the small town of Malargüe, Argentina. South Auger has only 1,600 water tanks and covers an area the size of Rhode Island.
Auger North is the second half of the project, located in the Northern hemisphere so scientists will have full-sky coverage.
There is now a small array of 10 experimental tanks in Colorado, Mantsch said, but construction for the full array has not been approved yet.
Mantsch said that about 90 percent of funding for the project in the United States comes from the U.S. Department of Energy and the National Science Foundation, and the current economic situation has put the project on hold.
Detection Apparatus
The scientists detect comic rays in two ways. Inside each water tank, is a photomultiplier tube, an extremely light-sensitive instrument that detects and records the tiny amounts of Cherenkov light, generated when cosmic rays pass through water in the tank.
The scientists also use florescence detectors, telescopes directed toward the sky above the tanks, which measure the ultra violet light created by the interaction of charged cosmic ray particles with atmospheric nitrogen.
Through these telescopes, scientists “can see the [cosmic ray] shower develop in the atmosphere. From the way it develops, it’s possible to tell something about the nature of the incoming particles, whether it’s heavy or light,” Mantsch explained.
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