The Institut Max von Laue-Paul Langevin (ILL) at Grenoble, France was formally founded in January 1967, with the signature of an intergovernmental convention between France and the Federal Republic of Germany. The aim was to provide the scientific community of the affiliated countries with a unique neutron beam facility applicable in fields such as the physics of condensed matter, chemistry, biology, nuclear physics, and materials science. The construction of the Institut and its high flux reactor was undertaken as a joint French-German project, with a total capital investment of 335 million French francs.

The reactor first went critical in August 1971 and reached its full power of 57 MW for the first time in December 1971. The year 1972 saw the startup of the cold and hot sources, the first instruments, and the beginning of the experimental program.

On January 1, 1973, the United Kingdom joined the Institut as a third equal partner, contributing its share to the total capital investment. In December 1986, an agreement on “Scientific Membership” for Spain was signed for a period of five years starting January 1, 1987. The ILL is a nontrading company under French civil law. The three countries are represented by the following associates: Kernforschungszentrum Karlsruhe GmbH (W. Germany), Centre National de la Recherche Scientifique (France), Commissariat à l'Energie Atomique (France), and Science and Engineering Research Council (United Kingdom). These associates are represented on a Steering Committee which establishes the general rules of the management of the ILL.