CERN Completes Magnet Set for Large Hadron Collider

CERN, the European Organization for Nuclear Research, took delivery of the last superconducting main magnet for the Large Hadron Collider (LHC) on Monday, completing the full set of 1624 main magnets required to build the world's largest and most powerful particle accelerator.

The LHC, initially conceived 22 years ago, is located inside a circular underground tunnel of 27 km circumference approximately 100 meters beneath Switzerland and France. When fully operational, it will reach seven times more energy than the most powerful particle accelerator currently in use. Scientists will use the LHC to recreate the conditions just after the Big Bang created the universe by colliding two beams of protons travelling in opposite directions at close to the speed of light.

LHC project leader Lyn Evans (left) and Lucio Rossi, head of the Magnets, Cryostats and Superconductors group, in front of the last superconducting main magnet delivered to CERN. Part of the long magnet can be seen on the back of the delivery truck, extending outside the right side of the photo's frame.

Thousands of magnets of different varieties and sizes will be used to navigate the beams of particles around the accelerator. These include the superconducting main magnets, of which 1232 dipole magnets of 15-m lengths are used to guide the beams, and 392 quadrupole magnets of 5- to 7-m lengths focus the beams. The main superconducting magnets make up about 22 km of the 27 km circumference of the LHC accelerator. Other magnets in the LHC were also provided by institutes outside Europe, from Canada, Japan, India, Russia, and the US.

The design of the magnets presented one of the most important technological challenges for the LHC. A high magnetic field is required to bend the path of the particle beam around the accelerator. To achieve this, the magnets must perform at the most efficient "superconducting" state without loss of energy, which requires chilling to a temperature of -271 °C throughout the LHC's operation, a temperature even colder than outer space.

CERN led the design and production processes of the dipole magnets, assembled by three European partners: Babcock Noell GmbH (Germany), Alstom MSA-Jeumont (a French consortium), and Ansaldo Superconduttori (Italy) using new techniques, including a new welding method for special stainless steel. The quadrupole main magnets were designed by CEA-DAPNIA laboratory (France), within the framework of the French special contribution to the LHC, and assembled by ACCEL Instruments (Germany). CERN's industrial partners said the challenges of building the LHC have resulted in innovations they can apply to other products, from magnetic resonance imaging machines to car manufacturing.

Assembly processes to complete the LHC are expected to finish by mid-2007, in preparation for its Nov. 2007 startup. Scientists said LHC will be central to the next generation of experiments at CERN, enabling scientific investigations that have never been possible before. The knowledge gained will shed light on the unresolved questions of science, such as the search for the elusive Higgs boson to explain the origin of particle mass, investigating the make up of dark matter and the existence of extra dimensions of space.

CERN also announced last week that the Barrel Toroid, the largest superconducting magnet ever built, has successfully been powered up to its nominal operating conditions. The Barrel Toroid provides a powerful magnetic field for ATLAS, one of the major particle detectors being prepared to take data at LHC.

For more information, visit: http://public.web.cern.ch