Title：A Historical Account of the First Electron-Positron Circular Collider – AdA 
Speaker：Prof.Jacques Haissinski 
Moderator：Prof.Gao Jie
Time: 15:00, Oct.9
Place: Room C305, IHEP Main Building

Abstract： 
The speaker will start by briefly recalling the first collider schemes proposed towards the end of the fifties and by a short discussion of the option electron-electron versus electron-positron colliders. Then he will describe the circumstances under which Bruno Touschek proposed to build the AdA e+-e- ring at the Frascati National Laboratories (Italy). He will describe the physics goals and the technical challenges underlying this project and give the main parameters of the ring. The initial successes and the difficulties met in Frascati will be presented. He will say why and how AdA was then brought to the Laboratoire de l’Accélérateur Linéaire (LAL) at Orsay. The results of the AdA runs at Orsay will be presented concerning the beam size and its lifetime. The “Touschek effect” which was then discovered and interpreted will be discussed. He will tell how the ring luminosity was determined. An overall review of the accelerator physics learnt with AdA will be given. What happened next in Europe in the collider field will end the lecture. 

About the speaker： 

1965 PhD degree: Experiments with the AdA collider 
1970 Physics professor at the Paris University 
1974-77 Vice-President of the Orsay Scientific Center 
1987-92 Deputy Director of the National Institute for Nuclear Physics and Particle Physics (IN2P3) 
1992-96 Head of the Department of Astrophysics, Nuclear Physics, Particle Physics and the Associated Instrumentation (DAPNIA) at CEA Saclay 
1990-93 Chairman of the “LEP Experiments Committee” du CERN