Simon van der Meer (24 November 19254 March 2011) was a Dutch particle accelerator physicist who shared the Nobel Prize in Physics in 1984 with Carlo Rubbia for contributions to the CERN project which led to the discovery of the W and Z particles, the two fundamental communicators of the weak interaction. Biography One of four children, Simon van der Meer was born and grew up in The Hague, the Netherlands, in a family of teachers. He was educated at the city's gymnasium, graduating in 1943 during the German occupation of the Netherlands. He studied Technical Physics at the Delft University of Technology, and received an engineer's degree in 1952. After working for Philips Research in Eindhoven on high-voltage equipment for electron microscopy for a few years, he joined CERN in 1956 where he stayed until his retirement in 1990. Van der Meer was a relative of Nobel Prize winner Tjalling Koopmans – they were first cousins once removed. In the mid-1960s, Van der Meer married Catharina M. Koopman; they had a daughter and a son. Work at CERN In the 1950s, Van der Meer designed magnets for the 28 GeV Proton Synchrotron (PS) In 1961, he invented a pulsed focusing device, known as the ‘Van der Meer horn’. Such devices are necessary for long-base-line neutrino facilities and are used even today. That was followed in the 1960s by the design of a small storage ring for a physics experiment studying the anomalous magnetic moment of the muon. Soon after and in the following decade, Van der Meer did some very innovative work on the regulation and control of powersupplies for the Intersecting Storage Rings (ISR) and, later, the SPS. Van der Meer's ISR Collider days in the 1970s led to his technique for luminosity calibration of colliding beams, first used at the ISR and still used today at the LHC, as well as in other colliders. The Nobel Prize committee recognised Van der Meer's idea of stochastic cooling and its application at CERN in the late 1970s and 1980s, specifically in the Antiproton Accumulator, which supplied antiprotons to the Proton-Antiproton Collider. During his work at the ISR, Van der Meer developed a technique using steering magnets to vertically displace the two colliding beams with respect to each other; this permitted the evaluation of the effective beam height, leading to an evaluation of the beam luminosity at an intersection point.