What Are They Doing?
A large international team of scientists and drilling technicians worked throughout the austral summer to continue to assemble and test the world's largest scientific instrument, the in-ice IceCube Neutrino Detector. Neutrinos are incredibly common (about 10 million pass through your body as you read this) subatomic particles that have no electric charge and almost no mass. They are created by radioactive decay and nuclear reactions, such as those on the sun and other stars. Neutrinos rarely react with other particles or forces; in fact, most of them pass through objects (like you, or the entire earth) without any interaction. This makes them ideal for carrying information from distant parts of the universe, but it also makes them very hard to detect. All neutrino detectors rely on observing the extremely rare instances when a neutrino does collide with a proton. This collision transforms the neutrino into a muon, a charged particle that can travel for 5-10 miles and generate detectable light.
IceCube is being constructed in Antarctica because the huge amount of dense ice under the South Pole contains a lot of protons that can be hit by passing neutrinos, and the ice is transparent, so the resulting light can be caught by sensors. IceCube is made up of 4200 sensitive light detectors embedded in the ice at depths between 1450 and 2450 meters (4700-8000 feet). The sensors were deployed on strings of 60 modules each, into holes 60 cm. in diameter in the ice, melted using a hot water drill. Covering about one square kilometer, IceCube expands on an existing experiment that started detecting neutrinos at the South Pole in 1997 (http://). Now complete, IceCube can detect up to 300,000 neutrinos a year for up to 20 years.
The data collected will be used to make a neutrino map of the universe and to learn more about cataclysmic astronomical phenomena, like gamma ray bursts, black holes, and exploding stars, and other aspects of nuclear and particle physics. However, the true potential of IceCube is discovery; the opening of each new astronomical window can lead to unexpected discoveries.
Where Are They?
The team worked from the Amundsen-Scott South Pole Station in Antarctica – the southernmost continually inhabited place on the planet. The IceCube site is about one kilometer from the new South Pole station, which supplies the necessary logistics of food, power, and shelter. The South Pole is reached by plane from McMurdo Station on the coast of Antarctica from October through February, after which temperatures become too low for planes to safely operate. Approximately 50 people stay through the rest of the year, which is known as wintering over. IceCube has two to three people dedicated to overseeing the operation of the telescope during this period at the South Pole.
Dr. Madsen is the chair of the Physics Department at UW-River Falls and Associate Director of the IceCube Neutrino Observatory where he directs the education and outreach program. His research interests include heliophysics and astrophysics, which he has studied at his various projects in Antarctica. In addition to research, Dr. Madsen is committed to reaching a broad audience beyond the research community. He is involved in education and outreach for the IceCube project including professional development courses for teachers and science and math instruction for the UWRF Upward Bound Program. He collaborates with a number of programs and institutions in addition to PolarTREC, including the Knowles Science Teaching Foundation, UW-River Falls Upward Bound and McNair Programs, and service groups (Rotary International, Boy and Girl Scouts, university alumni associations, etc.). You can read more about Dr. Madsen's work here and here.
"Working in Antarctica is a wonderful adventure, and it is great to provide opportunities for others to have this awesome experience."
Francis Halzen is a theoretician studying problems at the interface of particle physics, astrophysics and cosmology. Since 1987, he has been working on the AMANDA experiment, a first-generation neutrino telescope at the South Pole. AMANDA observations represent a proof of concept for the recently completed kilometre-scale observatory IceCube.
The current spokesperson for the IceCube collaboration is Tom Gaisser. He is the Martin A. Pomerantz Professor of Physics at the Univesity of Delaware. Tom is a well known astroparticle and cosmic ray physicist who promoted the concept of an array of detectors on the surface as part of IceCube.. Tom has been instrumental in getting an Antarctic Research page up at the University of Delaware where he and others have posted blogs from the South Pole.