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The Large Hadron Collider

The Development of the Project

Geneva, 17 June 1994. As early as 1977, during preparatory discussions for building CERN1's Large Electron Positron collider (LEP), it was clear that excavating the LEP tunnel would make more economic sense if it could be reused for a successor machine. Thus, while LEP was being designed and built in the early '80s, groups in CERN were busy looking at the longer term future.

In March 1984, participants in a joint European Committee for Future Accelerators (ECFA)-CERN Workshop identified exploration in the 1 TeV range as the correct next step in the world's particle physics programme. The first formal move towards the LHC came in 1985 when a Long-Range Planning Committee was convened to study future options for CERN. This committee judged that Europe would need a 1 TeV facility after full exploitation of LEP and that a proton collider ring installed in the existing LEP tunnel would be the most cost-effective method of reaching the required energy range. An intense R&D programme was started to establish the credibility of such a collider, and in June 1990, CERN's Scientific Policy Committee endorsed the proposal, with ECFA giving its backing later in the year.

In December 1991, following the review of a detailed technical report on the collider, the CERN Council stated that "the LHC is the right machine for the advance of ...(particle physics)... and of the future of CERN". In June 1993, detectors for proton-proton and heavy ion collisions had been chosen; additional smaller experiments for so-called B-physics are still under discussion. In December 1993, the LHC External Review Committee consisting of 14 world- class experts concluded that the design, expected performance and cost estimates for the LHC machine were all realistic.

When a detailed costing of the future CERN programme (including the LHC) was presented to the Council at the end of 1993, it was obvious that the existing CERN budget could not cover building the LHC on the desired time scale. The total cost to CERN of the LHC is 2,660MCHF. While most of this can be found within the current budget levels, completion of the LHC by the target date of 2002 for first physics would necessitate an extra 500MCHF over and above anticipated budget contributions between 1995 and 2005.

Various funding scenarios are under consideration to meet this shortfall, the most probable being important contributions from those non- Member States whose scientists will make substantial use of the LHC. Other possible sources of income include extra contributions from Member States, in particular the Host States. The difficulty is that the scale of additional support, especially from non-Member States, is unlikely to be clear until after the LHC has been given the go-ahead by the 19 CERN Member States. This conundrum was addressed at the last Council meeting on 15 April 1994. With only Spain abstaining, the Member States reaffirmed that the LHC is the right machine for CERN and that it should form the central element of the Laboratory's long-term programme. As far as funding was concerned, the Council declared that it "wishes to see the LHC implemented as part of the basic programme of the laboratory and wishes the project and its financing to be approved by general consensus". On that basis, the Council hopes to take a final decision on the LHC in June 1994.

1. CERN, the European Laboratory for Particle Physics, has its headquarters in Geneva. At present, its Member States are Austria, Belgium, the Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Italy, Netherlands, Norway, Poland, Portugal, the Slovak Republic, Spain, Sweden, Switzerland and the United Kingdom. Israel, the Russian Federation, Turkey, Yugoslavia (status suspended after UN embargo, June 1992), the European Commission and Unesco have observer status.