LHC - the aim of the exercise:
To smash protons moving at 99.999999% of the speed of light into each other and so recreate conditions a fraction of a second after the big bang. The LHC experiments try and work out what happened.

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Why? How? What?
3D interactive view of tunnel
[and how it was in 2005]


The Large Hadron Collider (LHC)  is built in a circular tunnel 27 km in circumference. The tunnel is buried around 50 to 175 m. underground. It straddles the Swiss and French borders on the outskirts of Geneva.

The first beams were circulated successfully on 10th September 2008. Unfortunately on 19th September a serious fault developed damaging a number of superconducting magnets. The repair required a long technical intervention. The LHC beam did not see beam again before November 2009.

First collisions took place on 30th March 2010 with the rest of the year mainly devoted to commissioning. 2011 was the first production year with over 5 inverse femtobarns delivered to both ATLAS and CMS. 2012 started well with over 6 inverse femtobarns delivered by the time of the summer conferences - these data paved the way for the announcement of a/the Higgs on 4th July 2012.

The LHC is designed to collide two counter rotating beams of protons or heavy ions. Proton-proton collisions are foreseen at an energy of 7 TeV per beam.

  • The beams move around the LHC ring inside a continuous vacuum guided by magnets.

  • The magnets are superconducting and are cooled by a huge cryogenics system. The cables conduct current without resistance in their superconducting state.


"Particle physics is the unbelievable in pursuit of the unimaginable. To pinpoint the smallest fragments of the universe you have to build the biggest machine in the world. To recreate the first millionths of a second of creation you have to focus energy on an awesome scale."
The Guardian

Taking a closer look at the LHC