In 1960 the prototype of an absolutely new kind of particle accelerator was designed and built at the Frascati National Laboratories following an idea of the physicist Bruno Touschek. AdA was a storage ring collider in which, for the first time, two separate beams - one of electrons and one of their antiparticles, positrons - were circulated in opposite directions and directed so as to clash head-on, making almost all the energy carried by the colliding particles available for producing massive new particles.

In the collision the electron and the positron disappear (annihilate) creating microscopic concentrations of energy that reconvert into a system of new particles in infinitesimal time spans. The innovative characteristic of a collision ring is that the sum of the energy from the two beams is totally used for the materialization of new particles. Most of the powerful accelerators operating in the world today, including the proton-proton collider LHC at CERN with its 14 TeV total energy and circumference of 27 km, are collision rings.

In early summer 1962, AdA was transferred to France, at LAL, the Laboratoire de l'Accélérateur Linéaire at Orsay, near Paris, where a high intensity linear accelerator (LINAC) was available.  This transfer led to the first experimental evidence of electron-positron collisions in a storage ring, and thus opened the era of electron-positron physics.

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