Mystery of cosmic rays might be solved by its radiation flashes

December 4th, 2007 - 1:24 pm ICT by admin  

Washington, Dec 4 (ANI): The mystery of the origin and source of cosmic rays might be solved by recording the radiation flashes which its particles emit, suggests a new research.
Cosmic rays are energetic particles originating from space that impinge on Earth’s atmosphere. Flying through the universe at nearly the speed of light, the most powerful c osmic rays contain more than one hundred million times more energy than the particles produced in the world’s most powerful particle accelerator.
But since the discovery of cosmic rays in 1938 by French physicist Pierre Auger, their origin has remained a mystery.
Though recent results from the Pierre Auger Cosmic Ray Observatory suggest that the highest-energy cosmic rays may come from the centers of active galaxies, the vast majority of the cosmic rays seen at Earth originate from its own galaxy, from sources that are still unknown.
Now, a new research by Scott Wakely, assistant professor in Physics at the University of Chicago, is aiming to develop an instrument that might reveal important new data about the nature and origin of cosmic rays.
Working in collaboration with Simon Swordy, the James Franck Professor in Physics at Chicago, the research team plans to make detailed measurements of Cerenkov radiation, which cosmic rays emit when they travel faster than the speed of light through the atmosphere.
“It’s possible that you get a particle which goes through the atmosphere faster than light does. And when that happens, you get the equivalent of a sonic boom, but with electromagnetic radiation. And that light boom is called Cerenkov radiation,” said Wakely.
Incoming cosmic-ray particles trigger two flashes of Cerenkov radiation. The first occurs when the original particle enters into the atmosphere, but the resulting shower of secondary particles also emits Cerenkov light. In an earlier study, David Kieda of the University of Utah, along with Swordy and Wakely, proposed a ground-based “direct Cerenkov technique,” whose basic idea was to record both the flashes of Cerenkov light.
As of now, many experiments have been designed to record the second flash of Cerenkov light. These include a collaboration called VERITAS (Very Energetic Radiation Imaging Telescope Array System), to which Swordy and Wakely belong.
The first scientists to see direct Cerenkov light belong to a European group that operate the High Energy Stereoscopic System (HESS), an array of telescopes in the African nation of Namibia. “They showed that even with non-optimum equipment, you could actually do something useful,” said Wakely. “With equipment designed to do this properly, we can do even better,” he added.
The idea behind direct Cerenkov detection was to combine the precision of balloon-borne cosmic-ray instruments with the far greater detection area afforded by ground-based arrays like VERITAS and HESS. “This is something that’s never been possible before,” said Wakely. (ANI)

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