First Critical Parts of Giant Neutrino Telescope in Place

MADISON — Working under harsh Antarctic conditions, an
international team of scientists, engineers and technicians has
set in place the first critical elements of a massive neutrino
telescope at the South Pole.

The successful deployment — in a 1.5 mile-deep hole drilled into the
Antarctic ice — of a string of 60 optical detectors designed to sample
phantom-like high-energy particles from deep space represents a key
first step in the construction of the $272 million telescope known as
IceCube.

The telescope and its construction are being financed by the National
Science Foundation (NSF), which will provide $242 million. An
additional $30 million in support will come from foreign partners.

“It’s all on track,” according to Francis Halzen, a University of
Wisconsin-Madison professor of physics and the principal investigator
for the project. “This was our first exam. We met our milestones for
the season and we can move on to the next Antarctic summer.”

In an announcement today (Feb. 15), scientists and managers of the
project declared a successful first season of construction of what will
become the world’s largest scientific instrument.

Building the telescope requires drilling at least 70
one-and-one-half-mile-deep holes in the Antarctic ice using a novel
hot-water drill, and then lowering long strings of volleyball-sized
optical detectors — 4,200 in all — into the holes, where they will be
frozen in place.

The first string, with 60 detectors, was successfully lowered into the
ice in late January, and communication with the detectors, each of
which is like a small computer, has been successfully established.

When completed, the telescope will utilize a cubic kilometer of
Antarctic ice as a detector, and will be capable of capturing
information-laden, high-energy particles from some of the most distant
and violent events in the universe. It promises a new window to the
heavens, and it may be astronomy’s best bet to resolve the century-old
quest to identify the sources of cosmic rays.

The IceCube telescope will look for the telltale signatures of
high-energy cosmic neutrinos, ghostlike particles produced in violent
cosmic events — colliding galaxies, distant black holes, quasars and
other phenomena occurring at the very margins of the universe. Cosmic
rays, which are composed of protons, are thought to be generated by
these same events. But protons are bent by the magnetic fields of
interstellar space, preventing scientists from following them back to
their points of origin.

Cosmic neutrinos, on the other hand, have the unique ability to travel
cosmological distances without being absorbed or deflected by the
stars, galaxies and interstellar magnetic fields that permeate space.
Their ability to skip through matter without missing a beat promises
unedited information about the early universe and the very violent
objects that populate deep space.

But that same phantom-like property — the ability to travel billions
of light years and pass unhindered through planets, stars and galaxies
— makes detecting cosmic neutrinos extraordinarily difficult.

“Neutrinos travel like bullets through a rainstorm,” Halzen explains.
“Immense instruments are required to find neutrinos in sufficient
numbers to trace their origin.”

The optical modules that make up the detector act like light bulbs in
reverse. They are able to sense the fleeting flash of light created
when neutrinos passing through the Earth from the Northern Hemisphere
occasionally collide with other atoms. The subatomic wreck creates
another particle called a muon. The muon leaves a trail of blue light
in its wake that allows scientists to trace its direction, back to a
point of origin, potentially identifying the cosmic accelerators —
black holes or crashing galaxies, for example — that produce the
high-energy neutrinos.

The telescope now under construction at the South Pole is an
international effort involving more than 20 institutions. The project
is funded by the U.S. National Science Foundation, with significant
contributions from Germany, Sweden, Belgium, Japan, New Zealand, the
Netherlands and the Wisconsin Alumni Research Foundation. In the U.S.,
the project involves scientists from UW-Madison, the University of
California at Berkeley, the Lawrence Berkeley National Laboratory, the
University of Maryland, Penn State University, the University of
Wisconsin-River Falls, the University of Delaware, the University of
Kansas, the University of Alabama, Clark Atlanta University, Southern
University and A&M College, and the Institute for Advanced Study.

“UW-Madison’s participation in this project has benefited
significantly from the willingness of Wisconsin’s Congressional
delegation to understand and support the science behind it,” says
UW-Madison Chancellor John D. Wiley. “The deployment of the first
IceCube string is the culmination of years of work to ensure that the
telescope would be built.”

This year marks the first year of work on the IceCube telescope, which
is being built around a much smaller neutrino telescope known as
AMANDA, for Antarctic Muon and Neutrino Detector Array.

“We’ve had an extremely productive year,” says Jim Yeck, the IceCube
project director. Accomplishments include fabrication of telescope
instrumentation at collaborating institutions; the shipment of almost 1
million pounds of cargo to the South Pole; assembly and successful
operation of the custom-built hot water drill; installation of
facilities and instrumentation on the ice, including surface tanks with
optical detectors (IceTop); and setting the first IceCube string into
the ice. The first IceCube strings included optical detectors produced
in Madison, Berlin and Stockholm. Data from the strings and the surface
tanks is now being successfully transmitted to the Northern Hemisphere.

The hot-water drill system alone was transported to the South Pole
from McMurdo Station on the Antarctic coast in 30 separate C-130
flights.

“We met all of the high-level milestones, including the most
significant one, the installation of a string,” Yeck says. Establishing
the project at the South Pole, setting surface equipment in place and
testing the powerful new drill meant the team had only a two-week
window to drill the first hole and deploy the first IceCube string.
Next year, with half of the three-month Austral season, the goal will
be to drill holes for and deploy ten or more strings.

Although significant progress was made this year, there were setbacks,
including an accident that injured a driller. The injured driller was
evacuated from the Pole to a hospital in New Zealand and has since
recovered.

“The safety of personnel living and working at the South Pole is an
extremely high priority, in particular given the environment and harsh
working conditions,” Yeck says. “We responded to the accident very
quickly by stopping drilling and placing equipment in standby mode
until the appropriate safety reviews could be completed and the factors
contributing to it could be addressed.”

Yeck added that undertakings like the IceCube neutrino observatory and
other polar science projects by U.S. researchers would not be possible
without the strong logistics and science support provided by Raytheon
Polar Services Co., the agency’s prime support contractor in
Antarctica, and without the strong support of the New York Air National
Guard for air cargo and personnel delivery, and the U.S. Coast Guard
for keeping sea lanes to the U.S. Antarctic coastal bases open.

Halzen expressed confidence the project would remain on track: “If we
stay on schedule, IceCube could take over next year as the world’s
largest neutrino telescope.”