IceCube

History

In the years 1970 and 1980, Soviet scientists launch an experiment, in the Antarctic, of detection of the radio signal emitted by neutrinos crossing the polar ice.

Following these too weak results, Francis Halzen, university of the Wisconsin (the United States) imagines: “I thus thought of exploiting the light Tcherenkov, a very held bluish flash generated by the collision of a neutrino with the core of a Atome in the ice. ”

The first experiment takes place in August 1990 with the Greenland, carried out by Bob Morse, with a budget of 50000 dollars of NSF. It makes it possible to detect Muon S coming from the interaction of the cosmic rays with the atmosphere.

In 1993, begins the project AMANDA (Antarctic Muon and Neutrino Detector Array). It showed that it was necessary to install the photomultipliers in 1400 depth meters lower part, because the ice, until this depth, contains tiny bubbles of air, deviating luminous flows Tcherenkov.

In 2005, begins the IceCube project. It will include AMANDA.

“Thanks to AMANDA, one recorded a murmur; with IceCube, one will listen to the sound of a double bass. ” (Francis Halzen)

Management of the project

Budget

The project costs 272 million dollars.

It is financed by the the National Science Foundation (NSF) to 90%. The remainder is financed by an international collaboration gathering the Germany, the Belgium, the Japan and the Sweden.

Men

Francis Halzen, University of the Wisconsin, chief of the IceCube project,
Bob Morse, developer of the detectors.

The scientific experiment

Detectors

IceCube will consist of 80 lines of detectors distributed in a Hexagone on one square kilometer.

Each one kilometer length line, is composed of 60 spheres of glass 50 centimetres in diameter, containing each one a Photomultiplicateur directed downwards. This line is placed in a well between 1450 meters and 2450 meters of depth.

There are thus 4800 Photomultiplicateur S distributed in a prism hexagonal right of one kilometer cubic (a photomultiplier every 17 meters in height).

Detection

The process of detection is the following:

the galactic Neutrino S and extragalactic, coming from the hemisphere celestial North, cross the Ground. This crossing makes it possible to eliminate the others particle S.
One from the neutrinos interacts with a Proton.
This interaction produces a Muon which will continue its race in the same direction.
In its voyage in the Ice, the muon produces a cone of Lumière by visible Effet Tcherenkov on approximately 250 meters.
This light is detected by various photomultipliers.
the light signals, converted into electrical signals are sent towards the stations of surface.

Construction

The site

This building site is located at the geographical south pole, with 2830 meters of altitude.

The calendar

The building site began in January 2005. It should finish in 2011.

In 2005, a first line of detectors was installed and tested successfully. Eight other lines were installed during the southern summer 2005/2006. Thirteen lines were installed during the southern summer 2006/2007, and then 14 to 18 lines are envisaged per annum.

Work can take place only six months per annum, during the southern summer.

Logistics

The equipment arrives mainly by air, thanks to Hercules LC-130.

A road, the Highway of the south pole, will be open since the station McMurdo, on the island of Ross, towards the south pole. It is a frozen track of 1.650 kilometers which would cross the Barrière of Ross and it transantarctic assembly line.

Drillings

To install each line of detectors, it is necessary to drill a well 60 centimetres in diameter on a 2450 meters depth. This well is drilled with warm water under pressure (61000 liters).

See too

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