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Headlines Published on 07 December 2006

Title International team successfully launches world’s largest superconducting magnet

The world’s largest superconducting magnet was successfully brought online recently as part of CERN’s Large Hadron Collider (LHC), the new particle accelerator scheduled for full scale use in November 2007. The magnet charged and operated successfully on its first attempt. The magnet, called the Barrel Toroid, provides the powerful magnetic field for ATLAS, one of the major particle detectors for LHC.

The experimental ATLAS detector began construction in 2004. © Nikolai Schwerg
The experimental ATLAS detector began construction in 2004.
© Nikolai Schwerg
The ATLAS Barrel Toroid consists of eight superconducting coils, each in the shape of a round-cornered rectangle 5m wide, 25m long and weighing 100 tonnes, all aligned to millimetre precision. It is designed to operate in concert with the other installed magnets to bend the paths of charged particles produced in collisions at the LHC.

A unique innovation behind the ATLAS detector is that it doesn’t require large amounts of metal to contain the magnetic field. The field is contained within a doughnut shape defined by the coils, allowing for the increased precision of its measurements.

ATLAS is the largest volume detector ever constructed for particle physics, measuring 46m long, 25m wide and 25m high. It has been designed to help researchers solve some of the most important questions in physics: Why do particles have mass? What is the unknown 96 percent of the Universe made of? and Why does Nature prefer matter to antimatter? Some 1800 scientists from 165 universities and laboratories representing 35 countries are building the ATLAS detector and preparing for its use next year.

Superconductors operate under cryogenic conditions and to reach the temperature of 269° C below zero, ATLAS was progressively cooled over a six-week period. It was then slowly charged up to 21 000 amps, 500 above the current needed to produce the nominal magnetic field.

“We can now say that the ATLAS Barrel Toroid is ready for physics,” said Herman ten Kate, ATLAS magnet system project leader.

The ATLAS Barrel Toroid is financed by the ATLAS Collaboration and has been built through close collaboration between the French CEA-DAPNIA laboratory (originator of the magnet’s design), Italy’s INFN-LASA laboratory and CERN. Components have been contributed by national funding agencies from France (CEA), Italy, Germany (BMBF), Spain, Sweden, Switzerland, Russia, and the Joint Institute for Nuclear Research (JINR), an international organisation based near Moscow.

More information:

  • ATLAS homepage
  • CERN homepage

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