Adieu ADONE

On April 26 the ADONE ring at Italy's Frascati National Laboratory was shut down for the last time. Giorgio Salvini, first Director of the Laboratory and presently President of the Lincei Academy, ''killed'' the last circulating beam in the machine. It was the end of a long and brilliant history, with an unusual interplay of technical skill, imagination and fruitful physics. The first design of ADONE was presented at a Frascati workshop at the end of 1960, while the four-metre circumference ADA machine, the world's first electron-positron storage ring, was being assembled. ADONE boosted beam energies from the ADA level of 250 MeV to 1500 MeV, with luminosity foreseen as 10³³ cm^-2 h^-1. Construction began in January 1963 and first beam-beam interactions were in the spring of 1969. In its characteristic operation mode, with three bunches per beam and 60+60 mA stored current, the maximum luminosity reached the design value in the collision energy range 2.0 - 2.4 GeV. The first significant and unexpected result came immediately: a copious production of hadronic states at energies far from the so-called rhotail. Hadrons were twice as copious than muon pairs, demonstrating dramatically the production of quark antiquark pairs and the role played by quark colour. Experiments continued in the search for higher recurrences of the already well-known vector mesons rho, omega and phi. However the first generation detectors, designed for a different scenario, did not have sufficient coverage nor magnetic field to analyse the final states. The next step came in 1973 with a second generation of experiments using more sophisticated detectors.. Also notable among the results of the first generation experiments were the study of the first photon-photon interactions and the production of proton-antiproton pairs