Bruno Touschek and AdA: from Frascati to Orsay. In memory of Bruno Touschek, who passed away 40 years ago, on May 25th, 1978

Abstract

The first electron-positron collisions in a laboratory were observed in 1963-1964 at the Laboratoire de l'Accélérateur Linéaire d'Orsay, in France, with the storage ring AdA, which had been constructed in the Italian National Laboratories of Frascati in 1960, under the guidance of Bruno Touschek. The making of the collaboration between the two laboratories included visits between Orsay and Frascati, letters between Rome and Paris, and culminated with AdA leaving Frascati on July 4th, 1962 to cross the Alps on a truck, with the doughnut degassed to 10 −9 mmHg through pumps powered by sets of heavy batteries. This epoch-making trip and the exchanges which preceded it are described through unpublished documents and interviews with some of its protagonists, Carlo Bernardini,

Bruno Touschek (1921–1978). The Path to Electron-Positron Collisions

“…They had an intense exchange of ideas during 1957-1958, at a time when much of Pauli's work was still centered on quantum field theory. 26 Such a dialogue with Pauli and with other theorists (notably Charles Enz, Gerhart Lüders, Markus Fierz, Kurt Symanzik, Luigi Radicati, Giacomo Morpurgo, Marcello Cini) was instrumental in the development of his ideas on QED and discrete symmetries, as well as in stimulating his own reflections on the CPT theorem, the solid conceptual base for AdA, as can be derived from correspondence of the period preserved within his papers at 'Edoardo Amaldi Archives' at the Physics Department of Sapienza University in Rome, and in published articles.…”

“…They also discovered an unexpected effect, a loss of particles from the stored beams reducing their lifetime, whose origin was immediately explained by Touschek as an intra-bunch scattering. But luckily, it turned out that the so-called Touschek effect scales sharply with energy and does not seriously affect more powerful colliders [26]. 21 In the meantime, the French started their own e + e − project, the collider ACO [29].…”

AdA at Orsay

“…Official negotiations between André Blanc-Lapierre, LAL's director, on the one side and Edoardo Amaldi, INFN director in Rome, Giorgio Salvini and Italo Federico Quercia, first and second director of the Frascati Laboratories (Fig. 3.6) on the other, led to AdA arriving in Orsay in July 1962 [7] and be installed at the experimental hall of the Laboratoire de l'Accélérateur Linéaire (Fig. 3…”