A telescope in a cubic kilometer of ice
University of Delaware (UD) scientists and engineers are currently working at South Pole under very harsh conditions. This research team is one of the many other ones working on the construction of IceCube, the world's largest neutrino telescope in the Antarctic ice, far beneath the continent's snow-covered surface. When it is completed in 2011, the telescope array will occupy a cubic kilometer of Antarctica. One of the lead researchers said that 'IceCube will provide new information about some of the most violent and far-away astrophysical events in the cosmos.' The UD team has even opened a blog to cover this expedition. It will be opened up to December 22, 2008. I guess they want to be back in Delaware for Christmas, but read more...
You can see above a drawing of IceCube. Here are the comments from Tom Gaisser, Professor of Physics and Astronomy at UD about these images. "Each line represents one cable. The darker dots between 1400 meters and 2400 meters each represent a digital optical module (DOM). The Eiffel Tower is shown for scale. The dots on the surface represent IceTop stations. Each station has two tanks filled with clear ice, and each tank has two DOMs embedded in the ice. IceCube is now half finished with 40 "strings" of DOMs and 40 IceTop stations. This season we are installing 16 more strings and 19 surface stations. The DOM consists of glass pressure vessel that contains a sensitive photomultiplier tube (PMT) that can detect individual photons of light, a computer and an atomic clock. Each clock is synchronized to a single GPS clock on the surface. The computer digitizes the profile of each signal, provides a time stamp and sends the data to the surface." (Credit: Tom Gaisser, UD; link to a larger picture)
The UD team is composed from many scientists and students belonging to the Bartol Research Institute which is part of the Department of Physics and Astronomy. They are maintaining a specific website about their Antarctic Research expedition. The blog mentioned above is accessible from this link.
But what is exactly the IceCube telescope? "Rather than a giant lens aimed at the heavens, the IceCube telescope consists of kilometer-long strings of 60 optical detectors frozen more than a mile deep in the Antarctic ice like beads on a necklace. Atop each string of deep detectors sits a pair of 600-gallon IceTop tanks, each containing two optical detectors. Ironically, it takes about seven weeks for the water in the IceTop tanks to freeze perfectly, without bubbles or cracks, which could obstruct the tiny flash that occurs when particles pass through the ice."
And why this future telescope is exclusively focused on neutrino research? "Neutrinos are among the most fundamental constituents of matter. Because they have no electrical charge and interact only weakly, these particles can travel millions of miles through space. Neutrinos can pass right through planets, and they can emerge from deep inside regions of intense radiation such as the accretion disk around a massive black hole. The surface IceTop detectors measure cascades of particles generated by high-energy cosmic rays showered down from above, while the detectors deep in the ice monitor neutrinos passing up through the planet from below. When a flash of light is detected, the information is relayed to the nearby IceCube Lab, where the path of the particle can be reconstructed and scientists can trace where it came from, perhaps an exploding star or a black hole."
For more information about the IceCube neutrino telescope, you can read this Wikipedia page if your time is limited. On the other hand, you can spend hours reading tons of information available from the IceCube official website at the University of Wisconsin, which is coordinating 33 institutions worldwide collaborating to this project.
Sources: Tracey Bryant, UDaily, University of Delaware, December 9, 2008; and various websites
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