CERN's two-year shutdown drawing to a close

February 13, 2015 by Cian O'luanaigh, CERN
A welder at work consolidating interconnections between dipole magnets on the Large Hadron Collider. Credit: CERN

It's almost two years to the day since the team in the CERN Control Centre switched off the beams in the Large Hadron Collider (LHC) at 7.24am on 14 February 2013, marking the end of the accelerator's first three-year run. Hundreds of engineers and technicians have been repairing and strengthening the laboratory's accelerators and experiments in preparation for running the LHC at the higher energy. So what has the work achieved?

When the LHC restarts this year, the energy of will be 13 TeV (or 6.5 TeV per beam) compared to 8 TeV (4 TeV per beam) in 2012. This higher energy will allow physicists to extend their searches for new particles and to check previously untestable theories.

To prepare the machine for this new energy frontier, 18 of the LHC's 1232 superconducting dipole magnets, which steer around the , were replaced due to wear and tear. More than 10,000 electrical interconnections between dipole magnets were fitted with splices – pieces of metal that act as an alternative path for the 11,000 amp current, saving the interconnection if there is a fault. The machine will operate at a higher voltage to run the higher energy beams, and has been fitted with new sets of radiation-resistant electronics. The vacuum system that keeps the beam pipe clear of stray molecules has been upgraded, and the cryogenics system for the LHC's superconducting has been refurbished.

Bunches of protons in the accelerator will be separated in time by 25 nanoseconds compared to 50 nanoseconds. The LHC will thus deliver more particles per unit time, as well as more collisions, to the experiments. To prepare for the challenges of more collisions, the LHC experiments, including ALICE, ATLAS, CMS and LHCb, underwent full consolidation and maintenance programmes, including upgrades to their subdetectors and data-acquisition systems.

A welder uses a custom-made orbital welding tool to seal an interconnection between dipole magnets on the LHC. Credit: Maximilien Brice/CERN

The CERN IT department purchased and installed almost 60,000 new cores and over 100 petabytes of additional disk storage to cope with the increased amount of data that is expected from the experiments during run 2. Significant upgrades have also been made to the networking infrastructure, including the installation of new uninterruptible power supplies.

When the LHC starts up again this spring, CERN's accelerators and experiments will be ready.

A 3D artist has dissected the LHC in this composite image, showing a cut-out section of a superconducting dipole magnet. The beam pipes are represented as clear tubes, with counter-rotating proton beams shown in red and blue. Credit: Daniel Dominguez/CERN

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5 comments

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Z99
2 / 5 (4) Feb 13, 2015
Be sure to fail to mention WHEN its scheduled to be turned back on. How useful. This article could have been written anytime in the last 2 (or 3) years with only the lede changed. Junk reporting.
TechnoCreed
5 / 5 (4) Feb 13, 2015
Be sure to fail to mention WHEN its scheduled to be turned back on. How useful. This article could have been written anytime in the last 2 (or 3) years with only the lede changed. Junk reporting.
My understanding is that the first proton beams will be injected on March 23rd but it is going to be low energy low luminosity (only a few bunches) mainly machine testing. The real physics should start on June 17 after the 50ns scrubbing operation and there will not be any 25ns bunches until July 25th. https://espace.ce...2015.pdf
TheGhostofOtto1923
3 / 5 (2) Feb 13, 2015
Be sure to fail to mention WHEN its scheduled to be turned back on. How useful. This article could have been written anytime in the last 2 (or 3) years with only the lede changed. Junk reporting.
I know. Typing is so HARD.
http://home.web.c...schedule

Junk commenting.
Lex Talonis
not rated yet Feb 14, 2015
Hmmmm I am just glad they didn't provide primary power with the salt water battery packs.

When they explode from inverse parallax back flows..... Oooooo the salt corrodes everything.
PhysicsMatter
not rated yet Feb 17, 2015
They will not start as long as there are winter temperatures in Switzerland, it may be late April before they turn it on. It is because they do not have enough power generated in local area to heat people's houses in the same time. But I would expect additional delays since the overhaul was massive not just a maintenance. It's odd because they claimed in 2010 that max. energy is 14 TeV not 13TeV. It seems they play safe.

This whole project is not optimal by design. Too much hugely expensive and unreliable cryo-technology. Much better and easier idea was linear accelerator like SLA or 100 km linear accelerator project, unfortunately scrapped in Texas in 1994, as a part of republican contract against America.

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