When a suitable amount of electrons and positrons have been gathered in the storage ring, they are steered into a circular accelerator called the PS. Here they are accelerated further to an energy of 3.5 GeV.
After the PS the particles are led into a bigger circular accelerator, the SPS, where they are accelerated to 22 GeV. Finally they are moved to the biggest circular accelerator, LEP. Inside LEP electrons and positrons can be accelerated to an energy of 104 GeV before they are made to collide to each other.