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.

The collaboration for A Large Ion Collider Experiment (ALICE) propose to build a detector at the LHC to study heavy-ion collisions. The letter of intent marks the first official use of the name ALICE.

Read the ALICE letter of intent

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

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.

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

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.

The CERN research board officially approves the ALICE experiment. Re-using the L3 magnet experiment from the LEP, ALICE is designed to study quark-gluon plasma, a state of matter that would have existed in the first moments of the universe.

In a seminar today the ATLAS and CMS experiments present the status of their searches for the Standard Model Higgs boson. Their results are based on the analysis of considerably more data than those presented at the summer conferences, enough to make significant progress in the search for the Higgs boson, but not enough to make any conclusive statement on the existence or non-existence of the elusive Higgs. The main conclusion is that the Standard Model Higgs boson, if it exists, is most likely to have a mass constrained to the range 116-130 GeV by the ATLAS experiment, and 115-127 GeV by CMS. Tantalising hints were seen by both experiments in this mass region, but they were not yet strong enough to claim a discovery.

The last superconducting magnet is lowered down an access shaft to the LHC. The 15-metre dipoles, each weighing 35 tonnes, are the most complex components of the machine. In total, 1232 dipoles were lowered to 50 metres below the surface via a special oval shaft. They were then taken through a transfer tunnel to their final destination in the LHC tunnel, carried by a specially designed vehicle travelling at 3 kilometres per hour.

The 53rd and final replacement magnet for the Large Hadron Collider (LHC) is lowered into the accelerator tunnel, marking the end of repair work above ground following the incident in September the year before that brought LHC operations to a halt.

The final magnet, a quadrupole designed to focus the beam, is lowered in the afternoon and starts its journey to Sector 3-4, the scene of the September incident. In total 53 magnets were removed from Sector 3-4 after the incident. Sixteen that sustained minimal damage were refurbished and put back into the tunnel. The remaining 37 were replaced and will be refurbished to provide spares for the future.