
The Large Hadron Collider Main Dipole. The main experiment at CERN is the Large Hadron Collider, or LHC. This accelerates protons or lead ions in two contra-rotating beams through a 27-kilometre tunnel that lies between 50 and 150 metres beneath the ground. The main dipole steers the beams while they are accelerated — the protons will end up travelling at a speed of around 300 metres per microsecond.








