Bigger and stronger: the next Large Hadron Collider

At the end of May, scientists from all over the world met in Berlin to discuss the successor to the Large Hadron Collider, the particle accelerator at CERN. This one they’re calling the Future Circular Collider, or FCC, which will be up to three times larger and seven times more powerful than the current LHC and aims to simulate energy levels much closer to those seen during the ‘Big Bang’. Tom Crawford heard about the project from physicist Carsten Welsch at the University of Liverpool…

Carsten - The fundamental driving question of all of this is why: why are we; why is universe the way it is; why do the fundamental forces behave in the way that they behave? A future collider can give us the insight that currently cannot be gained by using any of the facilities on Earth because we are limited in the ultimate energy of these colliders.

Tom - Can we not upgrade or extend the current Large Hadron Collider that we have?

Carsten - The fundamental problem is we need to look into what limits the performance of the current Large Hadron Collider. There are a few limitations and one of them is the ultimate achievable energy. Now the energy of a particle beam is provided to the particles by means of radio frequency power which is pumped into the accelerator and then transferred over to the beam. In order to keep that beam on a circular path you need magnets. There's simply not the technology available to bend a higher energy particle beam around the 27 kilometre circumference of the LHC so, at the moment, we want to go to higher beam energies. We need much stronger magnets in the existing tunnel or we need a larger tunnel in order to be able to store that kind of high energy particle beam.

Tom - Looking back at what we’ve learnt in the past from the LHC and from these kinds of experiments - of course there was the discovery of the Higgs Boson particle which is huge - but beyond the physics and understanding are there any other applications in everyday life?

Carsten - Absolutely. If you look at past colliders, every single particle collider lead to a breakthrough in our understanding of nature. It is not unlikely that there will be similar discoveries also in that energy range.

In terms of more tangible applications immediately for society, if you look back again in the history of particle physics, the impact on society can’t be overstated. For example, the internet itself was basically a spinoff from particle physics collaboration and what would we be today without the internet and mobile communications?

The magnets we talked about before are used nowadays routinely in hospitals for NMR diagnostics. So having access to better magnet technologies, even higher field strengths, would increase the resolution of such medical diagnostics automatically. The technologies that will be developed along the conceptual design of this machine will lead to breakthroughs that also impact on our lives every single day.

Tom - What is the main aim then of the FCC project?

Carsten - At the moment there’s an international community who looks into a conceptual design report. What will be required in order to build such a machine.

Tom - So it’s like you’re planning for the plan in some sense?

Carsten - Absolutely. At the moment the LHC has an expected lifetime of at least 20 years from now. So if you look at these timescales then the construction of the next machine would already take me pretty close to my retirement age. We need to engage the next generation of scientists, so these are really school kids today, to think about the questions we don’t have answers for at the moment. That they consider a career in science and also develop technologies that will benefit everyday life in the future.