The world's largest cyclotron

26 January 2000

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Seventy years ago, Ernest Lawrence published his idea for a circular particle accelerator - the basics of the cyclotron - in a short article in Science*. Lawrence's first successful cyclotron was some 10 cm across. Nowadays cyclotrons take a variety of forms and sizes, the world's largest being at TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics. In this image, a worker is checking the accelerator vacuum chamber for worn or damaged components. The diameter of the machine is about 18 m, and during the course of their acceleration in the machine, as they spiral outwards, protons travel a total of 45 km to reach maximum energy (520 MeV). The machine is now embarking on its second quarter-century of operation, having started up in December 1974.

( *see E.O.Lawrence and N.E.Edlefsen, Science, 72 376 (1930))

Credit: TRIUMF