David Warner (1934 - 2003)
It is with great sadness that we learned that our friend and former colleague, David Warner, passed away on Christmas Eve. The funeral was held the following Monday.
David was a "linac man". His career centred around linacs, but with a multitude of different subjects. He began at CERN by building the 3 MeV linac in the extension of the South Hall. He did pioneering work on this machine, which paved the way towards the design of the Alvarez cavities for the CERN Linac 2, for which he was responsible.
After this challenge was successfully finished, David was the first member of the small but growing team, that was in charge of building the LEP Injector Linacs (LIL). After having been recognised as a proton linac expert, he quickly converted to electron linacs where he soon became the respected key expert for the design, parameters and ultimate performance of LIL. His predilection for precise and detailed documentation, and his vision that the know-how acquired with LIL should be preserved and passed on to his younger colleagues, were an essential prerequisite to jump-start the CERN Linear Collider (CLIC) studies, the present research work that may still allow CERN to make a substantial contribution to a linear collider of the next generation.
With the CERN Heavy Ion Project, Dave returned to hadron linacs, this time to build a linac to accelerate lead ions. He invented a new structure, which he called the "Quasi Alvarez", which would have been able to cope with fairly high current beams. When it turned out that for financial reasons this machine could not be built, he was a loyal collaborator to get Linac 3 going, based on another principle.
David had a reputation of being precise and critical, and he was usually right when he questioned what was commonly assumed to be correct "by default", and in turn often he exposed hidden mistakes. David was not a perfectionist, yet his active mind rarely could be satisfied with a "first approximation to the optimal solution", and it was in this spirit that he introduced intelligent innovation and frequently more economical solutions. In this way David made an essential contribution towards CERN's long-term future.
Throughout his illness he maintained dignity and courage. We shall remember him as a friend and outstanding linac expert, who always tried to do things in the optimum way.