History
After World War 2, the rapid growth of nuclear physics and chemistry meant that research needed more and more powerful accelerators, which required large areas. The Université de Paris, the Ecole Normale Superieure and the College de France looked for space in the south of Paris near Orsay.
October 1954
The Parc de Launay in Orsay (160 hectares) was bought by the State.
1955
Construction began on the Institut de Physique Nucléaire (Nuclear Physics Institute) and the Laboratoire de l'Accélérateur Linéaire (Linear Accelerator Laboratory) by architect Seassal under the scientific direction of Joseph Pérès, Irène and Frédéric Juliot-Curie and Hans von Halban.
1957
The cyclotron of the College de France, built in 1937, was moved to Orsay.
1958
The first beams of the new French accelerators began to function (synchro-cyclotron of 157 MeV, and Linear Accelerator).
1958-1965
Some of the teaching activity of the Faculty of Sciences in Paris was transferred to Orsay. The rapid increase of students led to the independence of the Orsay Center on March 1st, 1965.
December 1970
The Université Paris-Sud 11 was founded with the integration of the centers of Orsay, Châtenay-Malabry, Sceaux, Cachan and Kremlin-Bicêtre.
Since 1970
The campus in Orsay began to expand on the plateau de Moulon with the founding of new laboratories which were almost all within Université Paris-Sud, although a few were more specifically linked to the CNRS or even with Paris VI University.
Because of the proximity of Université Paris-Sud to the CEA (Atomic Energy Institute) and to the laboratories of the CNRS in Gif sur Yvette, many institutes and laboratories, as well as academic schools (Polytechnique, HEC, IHES, ENSTA...) also came to this area. As a result, the Vallée de Chevreuse has become one of the most important and well-known areas in scientific research in Europe.

