The magic of superconductors in the spotlight

A superconducting magnet from the LHC on display outside the United Nations Office in Geneva during the EUCAS 2017 conference. (Image: Michael Struik/CERN)

A major conference on superconductors and their applications gets under way today in Geneva. Organised by CERN in collaboration with the University of Geneva and EPFL-SPC (Swiss Plasma Center) under the auspices of the European Society for Applied Superconductivity, EUCAS 2017 will welcome more than 1000 scientists and engineers to share the latest advances in superconductor technology and its applications.

It’s no coincidence that CERN is co-organising this conference. The Large Hadron Collider (LHC) is quite simply the biggest application of superconductivity in the world, with 23 kilometres of superconducting magnets around its 27-kilometre circumference.

The phenomenon of superconductivity was discovered in 1911. Below a very low critical temperature, some materials lose all of their electrical resistance. This amazing property opens up many exciting possibilities. Since there is no resistance to stop the flow of current and the superconductor does not heat up, it can carry far stronger electrical currents than “normal” or resistive conductors. A coil made from superconducting material can produce stronger magnetic fields than resistive electromagnets. This is the property that is of particular interest to particle physicists.

In circular accelerators like the LHC, particles are kept in their orbits by a magnetic field. But the higher the energy (speed) of the particles, the stronger the field needs to be. The energy of circular accelerators is therefore limited by the power of their magnets. At the end of the 1960s, this limit began to stand in the way of progress and superconductivity was exactly the innovation required to overcome it.

At the start of the 1970s, the idea really started being taken seriously. At the time, the most advanced work on the technology was being carried out by the “Energy Doubler” project at the Fermilab laboratory in the United States. This project later became the Tevatron, the first superconducting collider, which started operation in 1983. Its success really accelerated the use of superconductors for high-energy physics and since then, superconductivity and particle physics have driven each other on. Following the extraordinary technological achievement of the LHC, the future of superconductors is now taking shape in accelerator projects such as the High-Luminosity LHC and, in the longer term, bigger colliders able to push back even further the boundaries of the energy levels that humanity is able to explore.

This text is based on an article published in the September issue of the CERN Courier entitled “Powering the field forward”.