Long Shutdown 3
The third long technical stop of the LHC. A period of major rebuilding of the machine and the detectors: no collisions, but thousands of specialists in the tunnel.
CERN today
What is happening at CERN
Is the Large Hadron Collider running? When will the LHC restart? The four-year Run 3 collision programme has just ended and the longest technical stop in the machine's history has begun. Here is a dated status overview: what is happening now, what is planned and where it comes from.
As of: 2 July 2026
The LHC has ended Run 3 and entered Long Shutdown 3
In the early morning of 27 June 2026 the LHC produced the final collisions of Run 3. July opens LS3: a multi-year rebuild that prepares the machine for its high-luminosity era as the HL-LHC. The smaller accelerators of the complex keep running until the end of August, and the full work programme starts in September.
- 13.6 TeVcollision energy in Run 3
- 1.2 kmof machine rebuilt in LS3
- 10xmore data in the HL-LHC era
- ~91 kmplanned FCC circumference
Timeline: done, in progress, ahead
Future dates are official CERN plans, not guarantees.
- 2022 to June 2026
Run 3: a record LHC run
Four years of collisions at 13.6 TeV, the highest energy ever reached. CERN summed the run up as exceeding every expectation, with a record amount of data collected.
- 27 June 2026
The final collisions of Run 3
At 6 am the LHC Page 1 dashboard said goodbye to collisions. That closes the physics programme of the machine in its current form.
- from July 2026
Long Shutdown 3now
The biggest technical stop in the history of the LHC, planned to run to the end of the decade. About 1.2 km of the accelerator will be dismantled and rebuilt.
- 2026 to 2029
ATLAS and CMS detector upgrades
Both large detectors get an extensive overhaul to cope with 140 to 200 collisions per bunch crossing. During Run 3 that number was about 60.
- around 2028
The FCC decision
The feasibility study of the Future Circular Collider, a ring of roughly 91 km, was concluded in March 2025. Around 2028 the CERN member states are expected to decide on the next step.
- June 2030
HL-LHC start (Run 4)
The high-luminosity LHC is designed to collect up to 10 times more data than the programme so far. Its key next-generation magnets passed their tests in spring 2026 after cooling to 1.9 K.
Three abbreviations worth knowing
Everything you need to follow CERN news.
High-Luminosity LHC
The same 27 km machine after the upgrade: far more collisions per second, which means more data on the Higgs boson and on rare processes.
Future Circular Collider
A concept for the successor of the LHC: a ring of roughly 91 km. For now it is design work and analysis; a construction decision is expected around 2028.
Frequently asked questions about the LHC and CERN
Short answers to what people ask most often.
Is the LHC running right now?
No. On 27 June 2026 the Large Hadron Collider produced the final collisions of Run 3 and entered the long technical stop called Long Shutdown 3. The smaller accelerators of the CERN complex keep running until the end of August 2026.
When will the LHC restart?
According to the official CERN schedule a gradual restart begins towards the end of the stop, and full operation as the high-luminosity HL-LHC (Run 4) is planned from June 2030.
What is Long Shutdown 3?
It is the third long technical stop of the LHC and the biggest in its history. It covers dismantling and rebuilding about 1.2 km of the accelerator and an extensive detector overhaul that prepares the machine for the high-luminosity era.
How is the HL-LHC different from the LHC?
It is the same 27 km machine after an upgrade. New magnets and crab cavities let it deliver up to 10 times more data, which means sharper measurements of the Higgs boson and a better chance of spotting rare processes.
Will the Future Circular Collider be built?
The decision has not been taken yet. The feasibility study, concluded in March 2025, confirmed that a ring of roughly 91 km is technically feasible. The CERN member states are expected to decide on the next steps around 2028.
Can you visit CERN during the shutdown?
Yes. The Science Gateway visitor centre operates independently of the accelerator schedule, and the official CERN website lists the tours that are currently available.
Sources
- Long Shutdown 3, home.cern
- CERN bids farewell to the LHC and enters Long Shutdown 3, home.cern
- High-Luminosity LHC, home.cern
- Future Circular Collider, home.cern
This page does not fetch anything live. The content is curated by hand from official CERN announcements and stamped with the freshness date above.