When is CERN Large Hadron Collider New Test Run Begins?

Estimated date: June 1, 2030. CERN has scheduled the High-Luminosity Large Hadron Collider to start up in June 2030, with commissioning described as beginning around mid-2030. CERN has not announced an exact day, so June 1 is used as an estimated countdown date rather than a confirmed launch date.

When Will CERN’s Next LHC Test Run Begin?

The next planned LHC startup and testing period is expected in June 2030. It will follow Long Shutdown 3, a four-year programme of installation, maintenance and detector upgrades that began after the final LHC beams were removed in June 2026.

CERN’s published accelerator schedule places the start of High-Luminosity LHC operations in June 2030. A later project update says commissioning is scheduled for mid-2030. Until CERN releases a day-by-day restart plan, the exact first-beam and first-collision dates remain unconfirmed. The current timetable can be checked on CERN’s official accelerator schedule page.

What Is the Current Status of the Large Hadron Collider?

The LHC is not running particle collisions. It entered Long Shutdown 3 after its last beams were dumped on June 27, 2026. CERN announced the formal start of the shutdown phase on June 29, 2026.

The final weeks of Run 3 included high-intensity beam studies designed to test conditions expected in the upgraded machine. That 2026 test campaign has ended. The next startup will be the staged return of the rebuilt collider, followed by machine checks, beam commissioning and preparations for physics data collection.

CERN describes the shutdown and upgrade work on its Long Shutdown 3 page.

What Will Happen When the New Test Run Begins?

The LHC will not move directly from shutdown to full collision production. Restarting a particle accelerator of this size requires a sequence of checks and controlled beam tests.

Hardware and System Checks

Teams will verify the upgraded magnets, cryogenic systems, electrical circuits, beam-protection equipment, vacuum systems and controls. New High-Luminosity LHC components must work together under operational conditions before higher-intensity beams can be used.

First Beams and Circulation Tests

Low-intensity proton beams are expected to circulate first. Operators will measure the beam orbit, adjust magnets, test safety systems and confirm that the machine can transport beams reliably around the 27-kilometre ring.

Energy and Intensity Ramp-Up

Beam energy and the number of proton bunches will be raised in stages. Each step depends on stable machine performance and acceptable readings from protection systems. Delays can occur during commissioning because faults or unexpected beam behaviour must be studied before the next stage begins.

First Test Collisions and Physics Preparation

Initial collisions will be used to align and calibrate the experiments. ATLAS, CMS, ALICE and LHCb will test their upgraded detectors and data systems before routine physics operation begins. CERN may announce separate dates for first beams, first test collisions and the formal start of Run 4.

How Will the High-Luminosity LHC Differ?

The High-Luminosity LHC is an upgraded form of the existing collider, not a separate ring. CERN is replacing and adding equipment in selected sections of the machine so that experiments can record far more collisions over time.

The work includes new beam-focusing magnets, superconducting links, upgraded protection equipment and crab cavities that help the proton bunches overlap more effectively at collision points. ATLAS and CMS are also replacing large parts of their tracking, timing, electronics and data-handling systems.

CERN’s High-Luminosity LHC overview states that the upgraded collider should become operational in mid-2030.

Where Will the New LHC Test Run Take Place?

The testing will take place inside CERN’s Large Hadron Collider, a circular underground accelerator near Geneva. The ring crosses beneath land in both Switzerland and France. Operations are managed from CERN’s control facilities, while the main experiments sit at separate collision points around the ring.

This is a machine-operation milestone rather than a public event at one venue. There is no spectator area beside the collider during beam commissioning.

Can the Public Attend or Watch the LHC Restart?

There are no tickets for the accelerator test run itself. CERN may publish news updates, videos, control-room coverage or a webcast when first beams or first collisions approach, but no 2030 broadcast schedule has been announced.

Visitors can separately register for CERN Science Gateway and other public activities. Admission is free, subject to registration and availability. The LHC tunnel cannot be visited by families or individual visitors, and underground access is rare even for organised groups. Current options are listed on CERN’s official booking page.

When Will CERN Confirm the Exact Date?

A precise date is more likely after the upgrade work is advanced enough for CERN to publish the detailed Run 4 commissioning schedule. Accelerator restart dates can change because installation, testing and safety checks are linked. CERN may first announce a commissioning window, then publish separate dates for hardware tests, first beam injection, beam circulation and first collisions.

For now, June 2030 is the official planned startup month. June 1, 2030 remains an estimated marker for the countdown.

Questions About the CERN LHC Test Run

Is June 1, 2030 the confirmed start date?

No. CERN has confirmed June 2030 as the planned startup month and has referred to commissioning in mid-2030. It has not named an exact day.

Did a new LHC test run already take place in 2026?

Yes. CERN carried out high-intensity beam studies during the final part of Run 3 in June 2026. Those tests ended before the LHC entered Long Shutdown 3.

Will full physics collisions begin on the first day?

No. First beams, machine commissioning, detector calibration and collision setup are separate stages. Routine physics data collection will begin only after the collider and experiments are ready.

Is the High-Luminosity LHC a new collider?

It is a large upgrade of the existing LHC. The underground ring remains in use, while selected machine sections and experiment systems are replaced or improved.

Could the 2030 date change?

Yes. June 2030 is CERN’s current target, but the exact commissioning timetable depends on the completion and testing of the upgrade work.