The Large Hadron Collider

A Large Hadron Collider in the LEP Tunnel?

21 March 1984

CERN and the European Committee for Future Accelerators (ECFA) hold a workshop in Lausanne, Switzerland and at CERN from the 21-27 March 1984. The event, Large Hadron Collider in the LEP Tunnel, marks the first official recognition of the concept of the LHC. Attendees consider topics such as what types of particles to collide and the challenges inherent to high-energy collisions. The image above shows one proposal from the workshop – adding the LHC in with the existing LEP machine – that was later scrapped.  

Read the workshop proceedings

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US president announces support for Superconducting Super Collider

30 January 1987

With US President Ronald Reagan’s support, American physicists begin in-depth preparations to build the largest particle collider ever. The Superconducting Super Collider (SSC) – a circular accelerator with an 87-kilometre circumference – is designed to smash particles together at 40 TeV centre-of-mass energy. This would make the accelerator far more powerful than CERN's planned Large Hadron Collider (LHC). Construction begins in 1991 near Waxahachie, Texas. To some, the existence of the SSC project puts the need to build the LHC into doubt. Director-General Carlo Rubbia has to push to keep the LHC project alive.

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LEP tunnel completed

8 February 1988

The excavation of the tunnel for the Large Electron-Positron Collider – Europe’s largest civil-engineering project prior to the Channel Tunnel – is completed on 8 February 1988. The two ends of the 27-kilometre ring come together with just one centimetre of error. The picture above shows a tunneling crew after completing a section of the tunnel between points 2 and 3 on the LEP ring. 

The Large Electron-Positron Collider
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The history of CERN

ATLAS and CMS collaborations publish letters of intent

1 October 1992

The Toroidal LHC Apparatus collaboration propose to build a multipurpose detector at the LHC. The letter of intent they submit to the LHC Experiments Committee marks the first official use of the name ATLAS. Two collaborations called ASCOT and EAGLE combine to form ATLAS.

Read the ATLAS letter of intent

The Compact Muon Solenoid (CMS) collaboration proposes to build a multipurpose detector at the LHC. The letter of intent they submit to the LHC Experiments Committee marks the first official use of the name CMS.

Read the CMS letter of intent

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Superconducting Super Collider project cancelled

21 October 1993

Due to concerns linked to rising costs, the US government votes to cancel the Superconducting Super Collider project. The LHC becomes the sole candidate for a new high-energy hadron collider.

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10-metre magnet prototype achieves 8.73 Tesla

14 April 1994

The first prototype bending-magnet for the LHC reaches a field of 8.73 Tesla, which is higher than the 8.4 Tesla field at which the LHC will operate in 2012.

Superconducting magnets must be "trained" so that they can maintain the superconducting state necessary to achieve such high fields. Any abnormal termination of the superconducting state, which switches the magnet back to its normal, resistive state, is called a "quench."

LHC Director Lyn Evans receives a hand-written note as he sits in a Finance Committee meeting. It reads:

Message de J.P Goubier et R.Perin à L Evans
on a attaint 8,73 tesla
100 quench

They mean "sans quench" - a pun on the French word "cent" or "one hundred", which is pronounced the same as the word for "without".

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Japan admitted as CERN observer state

23 June 1995

The CERN Council admits Japan as an observer state. Japan announces a financial contribution to the LHC. The Japanese Minister for Education, Sciences and Culture offers a Daruma doll to CERN’s Director-General. According to Japanese tradition, an eye is painted on the doll to mark the beginning of the LHC project and the second eye must be drawn at the time of its completion. Japan makes two other major financial contributions to the LHC project in 1996 and 1998.

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LHC Conceptual Design Report published

20 October 1995

The Large Hadron Collider (LHC) project is approved by the CERN council in December 1994. The LHC study group publish the LHC Conceptual Design Report, which details the architecture and operation of the LHC, in October 1995.

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CERN accelerators


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