This week in 1956: CERN European synchrotron

As scientists prepare to switch on CERN's Large Hadron Collider and probe the mysteries of the universe, this article from the archives provides a fascinating insight into the origins of the world's most significant particle physics experiment.

It looks at the first annual report of CERN, otherwise known as the European Organisation for Nuclear Research, and details the development of the two accelerators that paved the way for the astonishing instrument we see today.

'The main installation will consist of two accelerators for research on high energy particles,' said The Engineer. 'One of these is a 600MeV synchro-cyclotron…the second is a 25GeV proton synchrotron.'

Describing the operation of the proton synchrotron, the article refers to 'a machine for accelerating positively charged particles by causing them to describe a circular path in such a way that during each circuit the particles receive one or more high frequency energy pulses. The particles are thus accelerated with each circuit of the circular path until they attain the required energy level, when they may be constrained to strike a suitable target.'

The key to this was the magnet. Rather than a continuous ring that had been used in smaller, less powerful synchrotrons, it was made up of 'a number of sections separated by RF accelerating cavities and focusing lenses.' This, wrote the magazine, would enable the particles to receive a series of accelerating impulses in each circuit rather than only one.

This system led to a series of immense engineering challenges, not least in the design of the foundations of the magnet system, 'the structure as a whole should be insensitive to temperature changes and ground movements. The diameter of the magnet ring is 200m and the load to be carried is made up mainly of the magnet iron (3,200 tons) and the coils (220 tons for copper, 110 tons for aluminium).'

Jon Excell