The history of CERN

CERN has come a long way since its foundation in 1954. This timeline collects the organization's major contracts, projects, partnerships and scientific advances.

20 11, 2006
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The ATLAS Barrel Toroid, then the largest superconducting magnet ever built, was switched on for the first time at CERN on 20 November 2006. The magnet is called the Barrel Toroid because of its barrel-like shape.

It provides a powerful magnetic field for ATLAS, one of the major particle detectors taking data at the Large Hadron Collider (LHC). The magnet consists of eight superconducting coils, each in the shape of a round-cornered rectangle, 5 metres wide, 25m long and weighing 100 tonnes, all aligned to millimetre precision.

The ATLAS Barrel Toroid was cooled down over a six-week period from July to August 2006 to reach –269°C . It was then powered up step-by-step to higher and higher currents, reaching 21 thousand amps for the first time during the night of 9 November. Afterwards, the current was switched off and the stored magnetic energy of 1.1 GigaJoules, the equivalent of about 10,000 cars travelling at 70 kilometres per hour, was safely dissipated, raising the cold mass of the magnet to –218°C.

Read the press release

31 07, 1974
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A few months after the signature of the agreement giving the go-ahead for the expansion of CERN into French territory, work began on the Super Proton Synchrotron (SPS). Two years later, on 31 July 1974, the Robbins tunnel-boring machine excavating the SPS tunnel returned to its starting point (see photograph). It had excavated a tunnel with a circumference of 7 kilometres, at an average depth of 40 metres below the surface. The tunnel straddled the Franco-Swiss border, making the SPS the first cross-border accelerator. More than a thousand magnets were needed to equip the ring. The civil engineering and installation work was completed in record time after only four years.

10 02, 1971
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Seven kilometres in circumference, the Super Proton Synchrotron (SPS) was the first of CERN’s giant underground rings. It was also the first accelerator to cross the Franco–Swiss border.

Eleven of CERN's member states approved the construction of the SPS in February 1971, and it was switched on for the first time on 17 June 1976, two years ahead of schedule. The SPS quickly became the workhorse of CERN’s particle physics programme, providing beams to two large experimental areas. Advances in technology during the building period meant that not only was construction finished early, it was able to operate with a beam energy of 400 GeV - 100 GeV higher than the original design energy.

The SPS operates today at up to 450 GeV, and has handled many different kinds of particles. Research using SPS beams has probed the inner structure of protons, investigated nature’s preference for matter over antimatter, looked for matter as it might have been in the first instants of the universe and searched for exotic forms of matter.

27 01, 1971
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By the late 1950s, physicists knew that a huge gain in collision energy would come from colliding particle beams head on, rather than by using a single beam and a stationary target. At CERN, accelerator experts conceived the idea to use the Proton Synchrotron (PS) to feed two interconnected rings where two intense proton beams could be built up and then made to collide. The project for the Intersecting Storage Rings (ISR) was formally approved in 1965.

On 27 January 1971 Kjell Johnsen (pictured), who led the construction team for the Intersecting Storage Rings (ISR), announced that the world's first interactions from colliding protons had been recorded. Pictured on the left are Franco Bonaudi, who was responsible for the civil engineering and Dirk Neet, who later took charge of ISR operations.

For the next 13 years the machine provided a unique view of the minuscule world of particle physics. It also allowed CERN to gain valuable knowledge and expertise for subsequent colliding-beam projects, and ultimately the Large Hadron Collider. For example, it was here that Simon van der Meer’s ideas to produce intense beams by a process called "stochastic cooling" were first demonstrated.

17 01, 1968
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In the 1960s, detection in particle physics mainly involved examining millions of photographs from bubble chambers or spark chambers. This was slow, labour-intensive and unsuitable for studies into rare phenomena.

Then came a revolution in transistor amplifiers. While a camera can detect a spark, a detector wire connected to an amplifier can detect a much smaller effect. In 1968, Georges Charpak developed the “multiwire proportional chamber”, a gas-filled box with a large number of parallel detector wires, each connected to individual amplifiers. Linked to a computer, it could achieve a counting rate a thousand times better than existing detectors. The invention revolutionized particle detection, which passed from the manual to the electronic era.

Charpak, who joined CERN in 1959, was awarded the 1992 Nobel prize in physics "for his invention and development of particle detectors, in particular the multiwire proportional chamber".

Today practically every experiment in particle physics uses some track detector based on the principle of the multiwire proportional chamber. Charpak has also actively contributed to the use of this technology in other fields that use ionizing radiation such as biology, radiology and nuclear medicine.

24 11, 1959
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The Proton Synchrotron (PS) accelerated protons for the first time on 24 November 1959, becoming for a brief period the world’s highest energy particle accelerator. With a beam energy of 28 GeV, the PS became host to CERN’s particle physics programme, and provides beams for experiments to this day.

During the night of 24 November 1959 the PS reached its full energy. The next morning John Adams (pictured) announced the achievement in the main auditorium. In his hand is an empty vodka bottle, which he had received from Dubna with the message that it was to be drunk when CERN passed the Russian Synchrophasotron’s world-record energy of 10 GeV. The bottle contains a polaroid photograph of the 24 GeV pulse ready to be sent back to Dubna.

When CERN built new accelerators in the 1970s, the PS’s principle role became to supply particles to the new machines. Since the PS started up in 1959, the intensity of its proton beam has increased a thousandfold, and the machine has become the world’s most versatile particle juggler.

In the course of its history the PS has accelerated many different kinds of particles, feeding them to more powerful accelerators or directly to experiments.

29 09, 1954
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At the sixth session of the CERN Council, which took place in Paris from 29 June - 1 July 1953, the convention establishing the organization was signed, subject to ratification, by 12 states. The convention was gradually ratified by the 12 founding Member States: Belgium, Denmark, France, the Federal Republic of Germany, Greece, Italy, the Netherlands, Norway, Sweden, Switzerland, the United Kingdom, and Yugoslavia. On 29 September 1954, following ratification by France and Germany, the European Organization for Nuclear Research officially came into being. The provisional CERN was dissolved but the acronym remained.

01 10, 1952
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Geneva was selected as the site for the CERN Laboratory at the third session of the provisional council in 1952. This selection successfully passed a referendum in the canton of Geneva in June 1953 by 16,539 votes to 7332.

It was selected from proposals submitted by the Danish, Dutch, French and Swiss governments. But Geneva's central location in Europe, Swiss neutrality during the war and that fact that it already hosted a number of international organisations all playing a role gave it the edge. While preparations were being made to establish the laboratory in Geneva, theoretical work would be carried out in Copenhagen.

13 12, 2011
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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.

30 04, 2009
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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.