The pioneers of nuclear and particle physics used naturally-occurring sources for their particle beams: Rutherford discovered the atomic nucleus and then disintegrated the nucleus of nitrogen using alpha particles from naturally occurring radioactive isotopes while many of the early discoveries in particle physics were made using cosmic rays.

However, there are problems with both methods. There is an upper energy limit of ~ 10 MeV for alpha particles which is insufficient for them to penetrate the strong electrostatic repulsive barrier around most nuclei. Some cosmic rays have far higher energies than any accelerator of today can produce, but their location and occurrence cannot be predicted, making them unsuitable for systematic studies. Work on building accelerators began in the late 1920’s with the first workable machines starting up in 1932.

Introduction        Direct voltage and cascade machines           Cyclotrons

Betatrons                    Linear accelerators and the synchrocyclotron                Synchrotrons       

    Fixed target verses collider machines        Lepton verses Hadron machines        The Future?