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Interactions.org - Particle Physics News and Resources

A communication resource from the world's particle physics laboratories

Interactions News Wire #09-08
6 February 2008 http://www.interactions.org
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Source: IceCube
Content: Seasonal Release
Date Issued: 1 February 2008
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CONTACT: Francis Halzen (608) 262-2667, halzen@icecube.wisc.edu; Tom Gaisser (302) 831-8113

Madison, Wisconsin—IceCube Construction reaches halfway point. The IceCube team exceeded their 2007-2008 seasonal stretch goal of 18 detector strings, four more than the project baseline plan. The 18 down-hole cables mark the halfway point in the construction of the neutrino telescope that will detect neutrinos with energies exceeding TeV. IceCube now consists of 40 strings, each instrumented with 60 digital optical modules (DOMs). The IceCube drilling and deployment teams were able to drill 2500 m deep holes at the South Pole and deploy strings at the rate of about one every 50 hours, creating a detector that now has a volume of one half a cubic kilometer.

Collaboration spokesperson, Tom Gaisser, says, “I am deeply impressed with the incredible job done by the skilled drilling and deployment team. The outstanding support from Raytheon Polar Services Company was essential for our success this season. It is a very exciting time for the IceCube Collaboration!”

Scientists are now evaluating each DOM to determine that it survived the deployment and “freeze-in” process. This testing and calibration effort continues after the last members of the IceCube construction team leave the South Pole on February 15th. The IceCube winter team then takes over the job of incorporating the new DOMs into the data acquisition system. So far 99 % of the deployed DOMs that have been powered on are working. There are now 2400 DOMs in the ice at the South Pole. IceCube will reach a km2-year exposure within two years—a long anticipated milestone of neutrino astronomy.

Not only has the team exceeded this season’s baseline plan they also finished the deployment ahead of schedule. This means there is plenty of time to prepare the site for next year’s season and suggests that construction of the detector will be complete in three more seasons as currently planned.

In addition to the deployed strings, and additional 28 IceTop tanks were installed this season, 80 overall. IceTop is a surface array to detect high-energy cosmic rays and to provide a veto for air showers that interfere with neutrino detection within IceCube. Weekly updates from this season can be viewed here: http://icecube.wisc.edu/news/index.php

The telescope now under construction at the South Pole is an international effort involving 28 institutions worldwide. The project is funded by the U.S. National Science Foundation (NSF), with significant contributions from Germany, Sweden, Belgium, Japan, New Zealand, and the Netherlands.