Tag Archives: IceCube

SCIENCE!

So many of you may be wondering by this point “working at the South Pole is cool and all, but…Why?”
Why are we here?
Why is there this giant station?
Why do we have US Air Force planes?
Why is there so much going on down here?

All of these questions, and more, can be answered with the one word: SCIENCE!Everything here is in support of research and for the most part funded through the US National Science Foundation (NSF).

The South Pole, with an elevation of nearly 10,000 feet, an average yearly temperature of -56.9F, and 6 months of darkness is an ideal site for astronomical observations. While there are numerous projects of both short and long term duration the two major ones are IceCube and the 10 meter South Pole Telescope.

NOAA (the National Oceanic and Atmospheric Administration) has a long term Earth Systems Research Laboratory monitoring site here. It’s part of several Global Monitoring Division sites – of which Summit Station, Greenland is also affiliated.

Over the next few posts I’ll highlight some of the primary research projects currently underway here at the South Pole.

ICECUBE
http://icecube.wisc.edu/

A good diagram showing the various parts of the IceCube detector

The IceCube project is a Neutrino detector. Sounds simple enough, but this detector is unlike any other in the world.
Neutrinos are sub-atomic particles of immense energy, but lacking an electric charge – so tiny and with so much energy that they pass through most matter without interaction. Neutrinos are a byproduct of radioactive decay and can be found many places here on earth, but IceCube is interested in a different scale. This project is focusing on neutrinos formed from extremely high energy events such as exploding stars, black holes, and gamma ray bursts. The project goals are to explain these events more thoroughly, shed light on dark matter in our universe, and study the more remote parts of the universe that previously have been too obscured to see. Neutrinos are not affected by magnetic fields, take an extremely long time to decay, and are rarely absorbed, putting them above neutrons or protons as useful particles to study the corners of the universe.

There are several detectors around the world, but the one here at Pole is particularly interesting as it is using the entire earth as a filter. Buried 1.5 kilometers beneath the ice surface the array spans a cubic kilometer! 5160 DOMs (digital optical module) were deployed on 86 vertical strings frozen within the ice sheet.
A hot water drill bored down to 2450m with 1000psi of near boiling water, leaving a tube of liquid water with a 24hr window before it began to freeze. A cable was lowered with the DOMs (61-64 per cable) attached at set intervals. Another part of the project is IceTop which deployed 324 DOMs in tanks on the surface. (http://icecube.wisc.edu/science/icetop) This is an immense project and took over 6 years to complete, the final string being deployed in December 2010. The detector has been collecting data since the first few strings were completed in 2006 and is expected to last another 20 years before the ice stretches and breaks the cables. An international collaboration, there are over 250 scientists around the world are analyzing the overwhelming amount of data being produced. With so many sensors in the ice and with such a large expense it’s good to know that there has been less than a 2% failure rate of the DOMs.

The idea behind having a three dimensional detector is that it is able to track the direction and speed of incoming particles. While many particles come from “above” here, they are noticed first by the IceTop array and can be weeded out, as muons or other various particles not necessarily neutrinos. Particles that come from “below” – or from the North Pole, travelling through the earth, are more likely to be actual neutrinos as most other things are essentially filtered out by the earth’s mass.

How many DOMs total are deployed within the ice here? 5484!
How many miles of copper wire are buried here to transfer data from the strings to the data center in the ICL (IceCube Lab)? 11,650 miles!
Some more fun facts can be found at: http://icecube.wisc.edu/about/facts
A fascinating article (with AMAZING pictures) by NPR about Neutrios and IceCube: http://www.npr.org/blogs/pictureshow/2011/02/24/133997980/cool-science-the-icecube-neutrino-observatory

The IceCube Lab or ICL – all the cables from the DOM strings come back to the ICL where the data is compiled and stored.

A few of the cables as they come together before entering the ICL

The hot water drill itself – the bowed out pieces are to keep the drill from spinning and oriented vertically

A hole over 2.5km deep!

A Digital Optical Module that us G.A.s got to sign last year

A few of the DOMs ready to be deployed on a cable

One of the last strings deployed last year

The DOMs are hung vertically and tensioned carefully so the cable bends around each sensor.

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Filed under Antarctic, Science, South Pole