Introduction

• 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.