In early February, CERN’s Select Board held a special meeting to discuss one important topic going forward: the next particle accelerator they will build. CERN is home to the Large Hadron Collider (LHC), the most complex single machine in the world. The proposed design for the next generation particle crusher for international collaboration is the Future Circular Collider (FCC), and is three times as long as the LHC.
The LHC is an extraordinary instrument. It has a 27-kilometer-long ring of superconducting magnets deep beneath Geneva, on the border between France and Switzerland. The LHC works thanks to the superconducting magnets that are kept just above absolute zero around the two giant tubes that are kept in an ultra-high vacuum. It is colder and emptier there than in interstellar space.
Bundles of protons (or sometimes heavy ions) travel through the tubes at almost the speed of light, and they collide with each other in one of four experiments. The collisions create conditions not seen in the universe since shortly after the Big Bang, and create a whole host of interesting particles. The crowning achievement was the discovery of the Higgs boson, the particle that (simplistically) gives all other mass.
Yet the LHC is limited. There are energies that cannot be achieved with such a machine – and for this reason researchers have wondered what the next step could be. A few years ago, CERN began investigating the proposal for the next particle accelerator, and after consultation between particle physicists across Europe and worldwide, the design emerged for an even larger circular machine: the Future Circular Collider.
At a distance of 90 kilometers, the proposed accelerator will be three times as long as the LHC and built twice as deep. If approved, it would begin construction in the early 2030s, begin destroying electrons in the 2040s, and move to destroying protons in the 1970s.
The goal would be to investigate the energies where direct evidence of dark matter and dark energy could be found. These energies simply lie outside the LHC – the protons in its beams cannot be pushed beyond a certain limit. To go beyond this, one approach is to build a much larger detector. All for a price tag of 15 billion Swiss francs, or about $17.2 billion.
However, the proposed plan is not without criticism. The project is being called a gamble because there is no guarantee that it will succeed in providing evidence of the elusive dark matter and dark energy, something the LHC has not yet done. The same could have been argued about the LHC and the discovery of the Higgs boson.
Of course, the discovery of that particle is not the only success of the LHC. In its first ten years of operation, nearly 3,000 scientific papers were published on its experiments – a huge impact on our understanding of particle physics.
Some scientists, policymakers and media have also labeled the cost of the proposed facilities as a waste of money, rather than seeing them as an investment in the construction and manufacturing industries in all countries that are part of CERN. CERN is also the birthplace of the World Wide Web, so you are only reading this because of an investment in the organization.
Another criticism is that the money should be spent on environmental projects to alleviate the climate crisis. Leaving aside the incorrect assumption that the two are mutually exclusive, the European Union – which includes many CERN members – has actually spent almost a hundred times as much on fossil fuel subsidies in 2022 as the cost of the proposed plan.
Ultimately, the decision whether the project is what CERN needs rests with the countries that pay for CERN membership. A study into the feasibility of the FCC will be completed next year. The European Strategy for Particle Physics will be updated in 2026, which may affect the plans. If the plans go well, the FCC could be approved in 2028 and a new generation of particle physics could begin.