LHC Machine Outreach

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  • The LHC is installed in a tunnel 3.8 m. in diameter, buried 50 to 175 m. below ground. The tunnel straddles the French-Swiss border to the North-West of Geneva. [see map above]
     

  • Two counter rotating beams are injected into the LHC from the SPS accelerator (the Super Proton Synchrotron).
     

  • The proton beams are injected at 450 GeV and then accelerated to 7 TeV.
     

  • The beam moves around the LHC ring inside a continuous vacuum chambers which pass through a large number of magnets.
     

  • 1232 dipole magnets bend the beam around the 27 km. ring. The momentum of the beam is very high and these magnets have to produce a very strong magnetic field.
     

  • To reach the high magnetic field required, high currents are needed. To avoid excessive resistive losses, the magnets are superconducting. A huge cryogenics system is required to produce the liquid helium needed to keep the magnets cold.
     

  • The cables of the magnets are of a very special design and conduct current without resistance in their superconducting state
     

  • The beams will be stored at high energy for 10 to 20 hours (with a bit of luck). In 10 hours the particles make four hundred million revolutions around the machine. During this time collisions take place inside the four main LHC EXPERIMENTS.

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