CERN Accelerating science


Feasibility Study

Over the last 50 years, particle colliders have been among the main scientific instruments used to understand the most fundamental particles and laws of the Universe. With its 27km circumference, the Large Hadron Collider (LHC) is currently the most powerful particle collider in the world. The High Luminosity phase (HL-LHC), will increase the machine’s discovery potential with a programme of research up to 2040. But CERN is already thinking beyond the LHC.

The future of high-energy physics in the 21st century hinges on designing and building colliders capable of pushing the energy and intensity frontiers by an order of magnitude beyond the present values. The Future Circular Collider (FCC) study explores different collider options, combined into a single research infrastructure built in a 100km underground tunnel, it can offer a solid and diverse physics programme extending beyond the end of the century.
FCC ring


A key recommendation of the 2020 update to the European Strategy for Particle Physics is that Europe, in collaboration with the worldwide particle physics community, should undertake a feasibility study for a next-generation hadron collider. As a result, from 2021 to 2027 the Future Circular Collider (FCC) feasibility study is investigating the technical and financial viability of such a facility at CERN.
The Feasibility Study includes a scientific component, numerous technical considerations as well as administrative and financial issues and massive work in terms of territorial feasibility, including: geological, environmental impact, infrastructures, and civil engineering.
If the outcome of the feasibility study is positive, CERN’s Member States and its international partners may endorse a more in-depth technical feasibility study of the project. This process could endorse the next steps towards the final approval of this project and start of construction after the middle 2030s, with the first step of an electron-positron collider (FCC-ee) beginning operations around 2045. A second machine, colliding protons (FCC-hh) in the same tunnel would extend the research programme from the 2070s to the end of the century.


Feasibility Study for a New Research Infrastructure.

The future collider would be built in a


ring-shaped underground tunnel located beneath the French departments of Haute-Savoie and Ain, and the Swiss canton of Geneva.

Well-known constraints restrict the layout to a limited area: the tunnel must avoid geologically complex areas; it must maximize the efficiency of future colliders; be connectable to the LHC; and the location of the surface sites must respect social and environmental constraints. For this reason, diverse variants of the layout are being considered, following the principles avoid, reduce, compensate to ensure a sustainable design, for future generations.
The FCC tunnel would house two colliders, one after the other. The first step, aimed to start operation in the mid 2040s, is an electron-positron collider (FCC-ee) that would provide unprecedented precision measurements and potentially point the way to physics beyond the standard model. The second step would be a proton-proton collider (FCC-hh) reaching energies up to eight times those of the LHC and offering new discovery potential.

Hosting different
particle accelerators
for the post-LHC era.
Profiting from CERN's
existing infrastructure.




surface points




meter depth (avg)

Up to 






decades of scientific research

FCC would be the most efficient and comprehensive scientific instrument for addressing the open questions in particle physics.

Successively hosting in the same tunnel a luminosity frontier electron-positron collider (FCC-ee) and an energy frontier proton-proton collider (FCC-hh).

Offering a shared and cost-effective technical and organizational infrastructure, like its predecessors, LEP and LHC.

Strengthen European leadership in physics research throughout the 21st century.


A Scientific Mission for the 21st century

The goal of the FCC is to push the energy and intensity frontiers of particle colliders, with the aim of reaching collision energies of 100 TeV in the search for new physics.The development of these colliders requires significant advances in many technologies. More than 150 universities, research institutes and industrial partners from all over the world are evaluating possibilities for new detector facilities: the associated infrastructure, cost estimates, global implementation scenarios, as well as appropriate international governance structures. 
One of the main concerns of the FCC collaboration is to make the future colliders sustainable, implementing energy efficient technologies and circular economy in all stages. The effective interplay of different science and technology domains is the key to success, and the potential for innovation with application in society at large is considerable.