Jean Gervaise 1921–2007
Jean Gervaise, a pioneer of metrology at CERN, passed away on 10 April. Under his leadership, metrology at CERN acquired international renown.
Despite the disruptions caused by the Second World War, Jean completed an engineering degree at the École Nationale des Sciences Géographiques in Paris, which led to a first job in the prestigious Geodesy Department of the Institut Géographique National (IGN). The rich experience he acquired here helped to form his great professional qualities, as well as the main traits of his character as a private individual and as a public figure. Jean not only had bold and pertinent technical ideas, he was also a flamboyant and experienced practical man who was not afraid to speak his mind.
Sent to CERN on a temporary mission by the IGN, he arrived with André Decae on 13 December 1954 to design the Proton Synchrotron positioning metrology, or "alignment", to use the official jargon. The project challenged the tools available at the time and thus required innovative solutions. The mission became a secondment that later resulted in the award of a first CERN contract starting on 1 January 1956. This marked the beginning of an extraordinary career imbued with the enthusiasm and innovative spirit of CERN's pioneers.
As the person in charge of what is generally known as the Survey Group (also Alignment, Metrology and Topometry, and Applied Geodesics over the years), Jean succeeded in meeting the increasingly challenging needs of successive machines and experiments, acquiring the necessary new skills, initiating the development of specific methods and instruments (distinvar-wire and laser-offset measuring devices) and achieving technical performances that gained him international recognition. His developments have found applications not only in particle accelerators but in many other scientific, technical and industrial domains.
Jean's remarkable innovations and achievements from the start of his career led to a brilliant PhD from the University of Munich in 1965. Passionate about geology and geomechanics, he looked back with particular fondness on the search for and geotechnical classification of possible sites for the Super Proton Synchrotron (SPS), which he regarded as one of the great periods of his career. Other highlights include technical and methodological developments for the underground north-finding gyroscopes, and his daring decision to base the piloting of the tunnelling machines for the SPS and the Large Electron–Positron (LEP) collider on unusually long distances between reference points issued from the surface, thus generating significant savings. The required precision seemed inconceivable but it proved a great success in both cases. The acquisition of an exceptional distance meter (known as the Terrameter, with a precision of 1 mm per 10 km) gave LEP the world's most precise geodetic network ever. This enabled conclusive checks of the high-precision geodetic use of GPS to be carried out, and the results were greeted with great excitement at a conference in 1985 on the first applications of GPS technology for precision positioning.
Jean was also a manager with an eye on both CERN's future and that of his colleagues, always concerned for their personal development, that they enjoyed harmonious relations and that they were happy in their work. Conscious of the importance of education and communication, he was particularly attentive to the training of young people. This was the start of a tradition that has been continued and even reinforced by his successors, as the group has welcomed more than 250 trainees. Following his retirement in 1986, Jean helped to found the CERN Pensioners Association and served a term of office as its chair.
It would be impossible to conclude without mentioning the man behind the public figure. He was a good and true friend to those who knew him, hospitable and generous, and always ready – together with his wife Madeleine – to welcome you to his home or to his table. We will not forget the happy times that we spent with him nor the warmth of his personality.
Michel Mayoud, successor to Jean Gervaise from 1986 to 2005.