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7 June, 2019
In the LHC tunnel during LS2 (Image: CERN)
Major endeavours have got under way way in the Large Hadron Collider (LHC) over the past few weeks, with the extraction of magnets from the accelerator tunnel. The LHC has a total of 1232 dipoles, magnets which bend the particles’ trajectories, and 474 quadrupoles, which squeeze the bunches. All these magnets are superconducting, i.e. they operate at a temperature of -271°C, are 15 metres long and weigh up to 28 tonnes. So moving them around is no trivial matter.
(Image: CERN)
During the second long shutdown, 22 of these large components (including 19 dipoles) have to be replaced, especially as several have been showing operating deficiencies. Twelve have already been brought above ground and the last one is scheduled to be dismantled at the beginning of July.
Exchanging LHC magnets at CERN
The replacement magnets are arriving one by one. Ten new magnets have been installed, aligned and are being connected in the first sectors of the accelerator (sectors 8-1 and 1-2). This involves reconnecting the beam-pipes, the superconducting cables that transport currents of up to 13 000 amps, the transfer lines for the helium that cools the magnets, the beam shields that thermally insulate the magnets once they have been cooled down to -271°C. Care needs to be taken to ensure the tightness of the insulating vacuum, and tests then are carried to check that the new magnets are perfectly interconnected with the neighbouring magnets. These operations take several weeks for each magnet ! All 22 magnets should thus be connected at the beginning of 2020.
Note:
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 23 Member States.
Related link:
Large Hadron Collider (LHC): https://home.cern/science/accelerators/large-hadron-collider
For more information about European Organization for Nuclear Research (CERN), Visit: https://home.cern/
Images (mentioned), Video (CERN), Text, Credits: CERN/Anaïs Schaeffer.
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