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.

It had all started with a visit to Frascati by Pierre Marin (1927-2002). After a period spent at CERN, Pierre Marin, who would later play a principal role in the French effort to accelerator building in post-war Europe, including research with ACO, was trying to find his own research direction and was told that in Frascati "[il] se passait des choses qui intriguaient les esprits''. In summer 1961, Pierre Marin visited Frascati, finding AdA to be  "un vrai bijoux'' and, on September 19, 1961, prepared a report of his visit, in which a collaboration between Frascati and Orsay is discussed.
Following Marin's visit, letters were exchanged between Frascati and Orsay. On December 22, 1961, André Blanc-Lapierre, the LAL Director wrote to Italo Federico Quercia, Director of Frascati Laboratories, that preliminary studies for a 1.3 GeV storage ring for electrons and positrons had started, and proposed a visit of French scientists from Orsay in the near future. François Fer, Pierre Marin and Boris Milman came thus to Frascati in early 1962. During their discussions with Carlo Bernardini and Bruno Touschek, the idea of bringing AdA to Orsay and obtain a higher luminosity thanks to the high intensity of the Orsay LINAC, took form.  By early April a decision to move AdA to LAL had been taken, and the transfer of AdA to Orsay was prepared.
At the beginning of July 1962 AdA was packed on a big truck, which had to cross the Alps with a fully evacuated beam pipe and with batteries lasting about three days to power the vacuum pumps: at that time, one needed months to reach the required extreme vacuum and one could not waste precious time to obtain it anew.

When the truck arrived at the Italian-French border, the custom officers wanted to inspect the inside of the doughnout. What was inside it? “Vacuum, the best possible vacuum”, was the answer. It would not suffice. It took high-level diplomatic interventions before AdA could  cross the border between France and Italy, with its high vacuum still intact. According to Jacques Haïssinski, who would do his doctoral thesis on AdA in Orsay,  "It took the intervention of Francis Perrin, then the Haut Commissaire à l'Énergie Atomique, to get over this hurdle''. Carlo Bernardini remembers also the intervention from the Italian side, with Edoardo Amaldi, Director of the Physics Department in Rome, calling the Italian Ministry of Foreign Affairs, and, through this, the French authorities.

By August 1962 AdA was installed in Orsay. During the installation, while being hauled by a heavy crane in its place, AdA was almost smashed against a wall. It was Pierre Marin, alerted by yelling from the Italian group, who ran and pushed the buttons that averted the crash. Later on, one of the detectors, while being moved close to the AdA ring, tipped over and broke Pierre Marin's foot. None of this could however quench the enthusiasm and drive of the Franco-Italian group, which was joined in the fall 1962 by Jacques Haïssinski.

In Orsay, thanks to the linear accelerator, collisions were observed and important effects in beam dynamics appeared. One such is the Touschek effect, immediately explained by Touschek. This effect limits the machine luminosity, manifesting itself through a progressive decrease in the beam lifetime while the number of stored particles increases, and is still one of the effects that limit the beam lifetime in accelerators.
Thus AdA opened the way to the machines that would discover new fundamental particles and bring the experimental confirmation of the Standard Model.