lundi 5 mai 2014

LHC consolidations: 27,000 shunts now in place

CERN - European Organization for Nuclear Research logo.

May 5, 2014

Since April last year, the Superconducting Magnets And Circuits Consolidation (SMACC) team has been strengthening the electrical connections of the superconducting circuits on the Large Hadron Collider (LHC). Last week they installed the last of 27,000 electrical shunts to consolidate "splices" – connections between superconducting magnets – on the accelerator.

Each of the LHC's 10,000 splices carries a hefty 13,000 amps. A shunt is a low-resistance connection that provides an alternative path for a portion of the current in the event that a splice loses its superconducting state.

Image above: An engineer uses a small mirror to inspect a shunt on an interconnection between superconducting magnets on the Large Hadron Collider (Image: Maximilien Brice/CERN).

On 19 September 2008, during powering tests on the LHC, a fault occurred in one of the splices, resulting in mechanical damage and release of helium from the magnet cold mass into the tunnel. Proper safety procedures were in force, the safety systems performed as expected, and no-one was put at risk. But the fault did delay operation of the accelerator by six months. The new shunts make such a fault unlikely to happen again.

To install a shunt the SMACC team first has to open the area around the interconnection they want to work on. They slide the custom-built metallic bellows out of the way and remove the thermal shielding inside, revealing a series of metallic pipes linking the magnets to each other. One set of these pipes – the "M-lines" – must then be cut open to access the splices between the superconducting cables. The team opened up the last of the M lines in February and has been at work ever since adding the shunts.

Check out some more of the main LHC consolidations:


CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 20 Member States.

Related link:

Large Hadron Collider (LHC):

For more information about the European Organization for Nuclear Research (CERN), visit:

Image (mentioned), Text, Credits: CERN / Cian O'Luanaigh.


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