Claude Détraz was born on 20 March 1938 in Albi, in the south of France. He graduated from the École Normale Supérieure and began his career at CNRS in 1962 as a researcher studying atomic nuclei.
Détraz then joined the Institut de Physique Nucléaire d’Orsay, founded by Irène and Fréderic Joliot Curie, which has now been merged with its neighbouring laboratories in Orsay to form the Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab).
At CERN’s Proton Synchrotron (PS), in collaboration with Robert Klapisch’s team, he contributed to the discovery of the first evidence of deformation in exotic nuclei at a shell closure. Drawing on these results, he became convinced that the beams at GANIL could also become a unique tool in this field.
Détraz was a great scientist and a true visionary, who played a major role in nuclear and particle physics in France and Europe. As the Director of GANIL (the Grand Accélérateur National d’Ions Lourds in Caen) from 1982 to 1990, he launched several research projects on exotic nuclei. The legacy of these projects is still with us today and will continue into the future. He was one of the main founders of NuPECC (the Nuclear Physics European Collaboration Committee) and was its first Chair from 1989 to 1992, cementing its position as the main coordinating committee for nuclear physics in Europe.
In 1991, Claude Détraz became a technical adviser in the office of the French Minister for Research, Hubert Curien, who was later the President of the CERN Council at the time of the LHC's approval in 1994. Through his involvement with decision-making bodies at all levels in France, Détraz made a major contribution to ensuring that the LHC project was approved. For example, he played a key role in Hubert Curien’s appointment as the President of the CERN Council, a position from which he was able to exert a major influence in the final phases of the decision.
As the Director of IN2P3 (Institut National de Physique Nucléaire et de Physique des Particules at CNRS) from 1992 to 1998, he helped to give the impetus, first with Robert Aymar and then with Catherine Cesarsky of the CEA, to France’s wholehearted participation in the LHC adventure. His involvement was essential in ensuring that France and its institutes played a leading role in the project.
In 1999, Luciano Maiani, CERN Director-General at that time, appointed him Director of Research, jointly with Roger Cashmore, until 2003. This was a period filled with important events for CERN, including the shutdown of LEP, the excavation of new caverns for the LHC and the start of a project to send neutrinos from CERN to the underground laboratory at Gran Sasso, to which Claude contributed substantially.
Throughout his career, Détraz promoted and supported interaction between scientific disciplines. As a nuclear physicist, he established strong links with particle physics. He was also one of the architects of the emergence of astroparticle physics, a discipline connecting the two infinities.
He received multiple honours both in France (commander of the Order of Merit, SFP Joliot-Curie prize, CNRS silver medal) and abroad (Gay Lussac-Humboldt prize from the Humboldt Foundation and an honoris causa doctorate from JINR Dubna).
I knew Claude Détraz throughout his time at GANIL, IN2P3 and CERN, and even afterwards. As well as being a brilliant scientist and occupying several high-level positions, he was a true “Enlightenment man” whom I appreciated for his commitment, efficiency, foresight and humanity. A man of great culture and finesse, he expressed himself in an elegant, convincing and moving way. His passing is a great loss that greatly saddens me. He was a shining light of our generation.
Michel Spiro, President of the International Union of Pure and Applied Physics, Chair of the CERN and Society Foundation Board, former Director of IN2P3 and former President of the CERN Council