It is the detectors that enable us to measure the energy and trajectories of the particles that are created in the collisions. With this information the types of particles can be determined.

Three types of detector are commonly used:

Delphi was one of the detectors in the LEP accelerator; it consisted of the different types of detectors mentioned above. Delphi has been removed to give room for Atlas, which is larger detector of the same kind that operates in the new LHC accelerator.