CERN's colliding-beam pioneers

24 January 2001

CERN's colliding-beam pioneers

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Thirty years ago, on 27 January 1971, CERN, the European centre for research in particle physics near Geneva, achieved the world's first ever interactions between colliding beams of protons, in a machine called the Intersecting Storage Rings (ISR). Here, Kjell Johnsen, who led the construction team which built the ISR, is seen making the announcement that the first collisions had been recorded. To the left are Franco Bonaudi (far left), who was responsible for the civil engineering of the project, and Dirk Neet, who later took charge of ISR operations. The machine stored proton beams in two interlaced rings, 300 m in diameter, after acceleration in CERN's Proton Sychrotron (PS). It was masterpiece of engineering, achieving an extremely good vacuum in order to store the beams, which collided where the rings crossed. The ISR closed down in 1984, having pioneered the way for future colliding-beam machines, in particular the Large Hadron Collider now under construction at CERN.

Credit: CERN Photo

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