The Daily Californian Online

Berkeley Lab Scientists at the South Pole Work to Collect Astronomical Data

By Kate Lyons
Daily Cal Staff Writer
Wednesday, January 26, 2011
Category: News > University > Research and Ideas

Lisa Gerhardt, Robert Stokstad, Sandra Miarecki, Spencer Klein, Mariola Lesiak-Bzdak and Thorsten Stezelberger (left to right) show off IceCube, a device intended to detect for neutrinos from the South Pole.

Roughly 10,000 miles from Berkeley at the South Pole, scientists from the Lawrence Berkeley National Laboratory are working on a project that hopes to provide information on large-scale astrophysical events.

Scientists with the IceCube project are using digital optical modules - extremely sensitive light detectors - to study events in the universe. By using these "IceCube" detectors, the researchers can record light caused by neutrinos - electrically neutral elementary particles - when they hit the ice surrounding the detector, allowing scientists to learn more about cosmic happenings such as gamma ray bursts and exploding stars.

The project is primarily funded by the National Science Foundation, with support from collaborators in Germany and Sweden. Construction and preparation for the project officially ended Dec. 18, but scientists at the South Pole are currently engaged in deploying the last strings of IceCubes and fixing last-minute technical issues.

"The main reason we are doing it is to learn more - there aren't a lot of spin-offs to affect daily life," said Spencer Klein, research physicist at UC Berkeley and principal investigator for the project.

IceCube's main goal is to look for sources of high-energy cosmic rays in the universe that originate from large events in space.

"The challenge is that these cosmic rays are electrically charged and are bent by magnetic fields as they travel through galaxies, making it difficult to trace their point of origin," Klein said. "Neutrinos, on the other hand, are electrically neutral and don't get bent - you just need a large detector like IceCube to pick them up."

The entire project covers a cubic kilometer, consisting of 86 drilled holes each filled with 60 detectors. The string of IceCubes - thick-shelled plastic spheres 33 centimeters in diameter filled with electronic components and light detectors - is buried 2,500 meters deep into the ice, which refreezes and secures them into place.

The IceCubes detect neutrinos by recording the rare burst of light created when a neutrino hits an atom of ice, recording the event within billionths of a second, according to Klein.

"You can think of it as a satellite," he said.

Two months into its operation, the IceCube project has collected data about neutrinos produced in Earth's atmosphere. The long-term goal for the project, says Klein, is to look for extraterrestrial neutrinos.

"Soon, we will start our regular run, which should last 10 to 20 years depending on what we find," Klein said. "We are looking for a lot of episodic things, such as bursts of neutrinos from high-energy gamma ray astronomy or from stars exploding. If we pick up a lot of episodic events, there is an argument to run the detector as long as it works."

UC Berkeley physics professor P. Buford Price, also involved in the project, said these extraterrestrial neutrinos trace back to an early period in the history of the universe and could also shed light on dark matter - matter that is believed to exist based on evidence of its effect on nearby objects but that has not been detected directly.

The IceCube project also promises to provide more information about events on planet Earth.

"I would say that our focus is primarily in the ice, and that enables us to do a variety of unrelated searches and experiments, such as in climate change," Price said. "We are also interested in understanding how tiny microbial cells blown on the ice from oceans can stay alive - a spin-off from high energy astrophysics but interesting to the scientific community anyway."

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