CERN has completed a feasibility assessment on a Future Circular Collider (FCC), a potential successor to the Large Hadron Collider (LHC), targeted for construction starting in the 2030s to aid scientists in revealing fundamental physics mysteries.
Thousands of physicists and engineers worldwide weighed in on the idea, and their input was collated into a report covering many aspects and potential concerns related to such a project, ranging from scientific effectiveness to environmental impacts. If constructed, the FCC would dwarf its predecessor with a 91-kilometer circumference compared to the LHC’s 27 kilometers.
Large Hadron Collider
More than 10,000 scientists in over 100 countries contributed across a decade to the design and construction of CERN’s previous model, the Large Hadron Collider. Completed in 2008, with the first collision occurring in 2010, the LHC allowed physicists to view the Higgs boson particle for the first time in 2012, confirming theoretical work predicting such a particle since the 1960s.
However, more work remains to be done in investigating fundamental physics mysteries. The discovery of the Higgs boson was a watershed moment for physics, as the particle was essential to the origin of matter, allowing electrons to gain mass immediately following the Big Bang. It may also hold clues to the universe’s final fate and other physics quandaries. Semiconductors, fusion energy, electricity transmission, and even the medical field all benefit from particle collider research.
Future Circular Collider Stages
The report’s outline breaks the project into two stages designed to meet the 2020 European Strategy for Particle Physics priorities. Geological fieldwork for the study began in 2023 and concluded this year. In addition to its 91-kilometer circumference, the FCC will have an average depth of 200 meters with eight surface protruding sites. In total, the collider will be able to host up to four experiments at the same time.
In its first stage, the FCC would consist of an electron-positron collider where physicists could develop Higgs, electroweak, and top-quark particles. That stage would allow for the most precise particle measurements ever recorded, potentially unlocking new knowledge beyond the standard physics model.
The second stage would push collision energy to an unprecedented 100 TeV to create a proton-proton collider, eight times the power of LHC. Currently, CERN’s timeline predicts the first phase to come online in the mid-2040s, with the second phase not following until the 2070s. While the timeline may seem long, LHC was first proposed in 1984, approved in 1994, and finally online in 2010.
The Many Considerations of the FCC
Beyond the scientific advancements the project may generate, the report covers essential factors stakeholders must weigh when considering whether the FCC should proceed. These include potential environmental impacts, socioeconomic benefits, and cost. Throughout the study, CERN has engaged with local, regional, and national organizations in its host countries, France and Switzerland.
While some public meetings took place last year, further opportunities for the public to weigh in on the FCC plans are currently in the works.
CERN is focused on pursuing an environmentally friendly design, not just during construction and operation, but through eventual dismantling. They hope the FCC will boost new technologies while synergizing with local resources for reusable energy. Laying out and placing the collider ring and its support infrastructure has been thoroughly studied to balance its scientific needs with environmental, construction, and cost considerations. Planners considered 100 different ideas for how to build the FCC before settling on the current parameters.
Making the Decision and Paying for it
Current estimates place the cost at $15 billion Swiss francs, almost USD 17 billion, to be spent over 12 years beginning in the early 2030s. Those funds would be allocated from CERN’s current annual budget towards FCC’s civil engineering, technical infrastructure, electron and positron accelerators, and four detectors.
While the feasibility report is complete, many hurdles remain before the FCC receives any commitments from CERN or its Associate Member States. Multiple independent organizations are reviewing the proposals before the CERN Council meeting to discuss the study scheduled for November 2025. It may not be until 2028 when the CERN Council decides if they will approve the FCC.
Volumes one, two, and three of the Future Circular Collider Feasibility Study Report are available for public viewing at the CERN website.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.