Full Breakdown
LHC Enters Long Shutdown for High-Luminosity Upgrade
6/30/2026, 11:19:12 AM
Background and Upgrade Timeline
The Large Hadron Collider (LHC) at CERN began circulating beams in 2008, delivered the 2012 Higgs boson discovery and over 85 hadrons, and completed three runs. On 29 June 2023 it entered its longest pause—47 months of Long Shutdown 3 (LS3). LS3 will replace 1.2 km of magnets, install crab cavities, and refurbish ATLAS and CMS, preparing the High-Luminosity LHC (HL-LHC) for a 2030 start with up to ten-fold higher luminosity.
Canada’s Role in the ATLAS Inner Tracker
Canadian groups at Simon Fraser University, TRIUMF, the University of British Columbia and industry in Toronto and Ottawa are building 84 silicon “petals” for the ATLAS inner tracker—about 20 % of the detector. Five petals and prototypes have been shipped to Germany for assembly; each undergoes cryogenic testing at TRIUMF before export.
Upgrade Technical Objectives
The HL-LHC will raise the collision rate from 2.4 billion to roughly 24 billion interactions per second, a ten-fold increase. This requires narrower proton bunches, higher beam intensity and crab cavities that rotate the beams for optimal overlap. The new inner tracker will record billions of particle trajectories, enabling finer Higgs measurements.
Scientific Significance
With an anticipated 380 million Higgs bosons, the HL-LHC will allow precision studies of the particle’s couplings and searches for rare decays that could reveal dark-matter candidates or other physics beyond the Standard Model.
Official Statements
CERN Director for Accelerators and Technology Oliver Brüning said the LHC “has exceeded every expectation” and that the shutdown marks a deliberate farewell to the machine. LS3 Coordination Lead Jean-Philippe Tock called the programme “a huge and complex logistical and engineering undertaking” involving thousands of specialists.
On-the-Ground Perspectives
Project leader Markus Zerlauth noted the goal to “increase the collision rate by a factor of 10.” TRIUMF manager Luise Poley warned that “the clock is ticking” as the deadline approaches. Undergraduate Madison Levagood called testing a petal in a freezer “incredibly exciting,” emphasizing its contribution to the experiment.
Conflicting Reports
Earlier coverage mistakenly said Canada would produce about 1,500 petals; the corrected figure is 84 petals comprising roughly 1,500 individual segments.
Verbatim Quotes
- “The LHC has exceeded every expectation,” — Oliver Brüning, CERN Director for Accelerators and Technology
- “The LS3 represents a huge and complex logistical and engineering undertaking,” — Jean-Philippe Tock, Head of the LS3 Coordination Team
- “Our goal is to increase the collision rate by a factor of 10,” — Markus Zerlauth, overall project leader for the upgrade
- “The clock is ticking,” — Luise Poley, TRIUMF scientist and project manager
- “it’s incredibly exciting,” — Madison Levagood, UBC undergraduate researcher
- “The theory landscape is wide open in terms of breakthrough discoveries, but we need the data to really shed light on this,” — Bernd Stelzer, Simon Fraser University professor
What's Next
HL-LHC commissioning begins 2028; physics runs start 2030.
