The basic components

In CERN particle accelerators, the same basic components are needed as in a television set: something to accelerate the particles, something to bend them, something to focus them, a vacuum for them to travel through plus something to house the whole lot.

The accelerating component: the cavity

Charged particles receive the energy needed to reach a speed close to that of light from sophisticated accelerating cavities like the one illustrated here. These cavities store up electrical energy, transferring a small amount to the particles each time they pass. They act like a short section of linear accelerator.

The bending component: the dipole magnet

Magnets called dipoles are used to keep the particles moving in a circle. Each time more energy is pumped into the particles, the magnetic field has to be increased to prevent them from skidding off the ring.

The focusing components: the quadrupole and sextupole magnets

Other magnets, called quadrupoles and sextupoles, are used to keep the particles tightly packed within the beam. They work in much the same way as lenses do with light.

The race track: the vacuum chamber

In particle accelerators, to ensure that particles are not lost by colliding with molecules of air, they travel inside a pipe, from which all the air has been removed. Vacuum pumps all around the ring ensure that there is even less matter inside the beam pipe than there is in outer space.