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Large Hadron Collider First Beam

Category: Science & Technology Key figures: Robert Aymar (CERN Director-General), Lyn Evans (LHC Project Leader), Peter Higgs (theoretical physicist whose predicted boson was a primary search target)

Summary

On September 10, 2008, at 10:28 AM local time, CERN successfully circulated the first proton beam through the full 27-kilometre ring of the Large Hadron Collider (LHC) at its facility on the Franco-Swiss border near Geneva, Switzerland. The moment — marked by two bright dots on a control-room screen — was broadcast live to a global audience estimated at over one billion people, with the BBC dedicating an entire day’s radio coverage to the event. CERN’s website recorded a record number of simultaneous visitors, and approximately 2,500 television broadcasts and 6,000 press articles covered the milestone. Scientists and journalists at CERN dubbed it “First Beam Day.”

The LHC is housed in a circular tunnel 100 metres underground, originally constructed for CERN’s previous accelerator, the Large Electron-Positron Collider. The machine contains 1,232 dipole superconducting magnets that bend the beam around the ring, chilled to 1.9 K (−271.25 °C) — colder than outer space — using liquid helium. Construction of the LHC began in earnest in 1998 after the LEP was decommissioned; the total cost was approximately $4.75 billion (roughly €7.5 billion for accelerator and detectors combined), making it the most expensive scientific instrument ever built at that time. The accelerator was designed to collide two beams of protons at centre-of-mass energies of up to 14 TeV to recreate conditions approaching those that existed just after the Big Bang.

Nine days after the triumphant first-beam event, on September 19, 2008, a faulty electrical bus connection between two superconducting dipole magnets in Sector 3-4 caused a resistive voltage spike at 9 kA, triggering a quench that released approximately six tonnes of liquid helium into the tunnel, ripping magnets from their concrete anchors. The sector had to be warmed up for inspection and repair, delaying full LHC operations by more than a year. Beam circulation and the first low-energy collisions did not resume until November 2009, with the first high-energy collisions (7 TeV) achieved on March 30, 2010. The LHC eventually fulfilled its central scientific mission when, on July 4, 2012, CERN announced the discovery of a particle consistent with the long-sought Higgs boson.

Significance

The first-beam event of September 10, 2008 represented the culmination of roughly two decades of planning, engineering, and international collaboration involving more than 10,000 scientists and engineers from over 100 countries — the largest scientific collaboration in history. The LHC fundamentally changed particle physics by providing the collision energies necessary to probe the electroweak scale and test the Standard Model in previously inaccessible regimes. Its construction demonstrated that nations could cooperate at unprecedented scale and cost on a purely fundamental-science endeavour. The subsequent 2012 Higgs-boson discovery, enabled directly by this 2008 milestone, confirmed the last major missing piece of the Standard Model, the mechanism by which elementary particles acquire mass, validating decades of theoretical work and earning Peter Higgs and François Englert the 2013 Nobel Prize in Physics.

Sources

• Large Hadron Collider — CERN official page
• CERN Large Hadron Collider is powered up — History.com
• The day the world switched on to particle physics — CERN Courier
• First Beam for Large Hadron Collider — Lawrence Berkeley National Laboratory
• Incident in LHC sector 3-4 — CERN press release

Related

• SpaceX Falcon 1 First Orbital Launch — Another landmark scientific milestone of September 2008, demonstrating the breadth of transformative events in a single month.
• 2008 Beijing Summer Olympics — The global spectacle of the Olympics preceded the LHC first-beam by weeks in a remarkable summer of 2008.