During the first half of this century, achievements in Europe dominated progress in the physics, from the discovery of the electron to the atomic nucleus and its constituents, from special relativity to quantum mechanics. Sadly, the conflicts of the 1930s and 40s interrupted this as many scientists had to leave for calmer shores. The return of peace heralded some decisive changes. By the early 50s, the Americans had understood that further progress needed more sophisticated instruments, and that investment in basic science could drive economic and technological development. While scientists in Europe still relied on simple equipment based on radioactivity and cosmic rays, powerful accelerators were being built in the US. Table-top experiments were being overtaken by projects involving large teams of scientists and engineers.
A few far-sighted physicists, such as Rabi, Amaldi, Auger and de Rougemont, perceived that co-operation was the only way forward for front-line research in Europe. Despite fine intellectual traditions and prestigious universities, no European country could cope alone. The creation of a European Laboratory was recommended at a UNESCO meeting in Florence in 1950, and less than three years later a Convention was signed by 12 countries of the Conseil Européen pour la Recherche Nucléaire. CERN was born, the prototype of a chain of European institutions in space, astronomy and molecular biology, and Europe was poised to regain its illustrious place on the scientific map.
CERN exists primarily to provide European physicists with accelerators that meet research demands at the limits of human knowledge. In the quest for higher interaction energies, the Laboratory has played a leading role in developing colliding beam machines. Notable "firsts" were the Intersecting Storage Rings (ISR) proton-proton collider commissioned in 1971, and the proton-antiproton collider at the Super Proton Synchrotron (SPS), which came on the air in 1981 and produced the massive W and Z particles two years later, confirming the unified theory of electromagnetic and weak forces. The main impetus at present if from the Large Electron-Positron Collider (LEP), where measurements unsurpassed in quantity and quality are testing our best description of sub-atomic Nature, the Standard Model, to a fraction of 1% soon to reach one part in a thousand. By 1996, the LEP energy was doubled to 90 GeV per beam in LEPII, opening up an important new discovery domain. More high precision results are expected in abundance throughout the rest of the decade, which should substantially improve our present understanding. The LEP/LEPII missions will by then be largely completed.
LEP data are so accurate that they are sensitive to phenomena that occur at energies beyond those of the machine itself; rather like delicate measurement of earthquake tremors far from an epicentre. This gives us a "preview" of exciting discoveries that may be made at higher energies, and allow us to calculate the parameters of a machine that can make these discoveries. All evidence indicates that new physics, and answers to some of the most profound questions of our time, lie at energies around 1 TeV (1 TeV = 1,000 GeV).
To look for this new physics, the next research instrument in Europe's particle physics armoury is the LHC. In keeping CERN's cost-effective strategy of building on previous investments, it is designed to share the 27-kilometre LEP tunnel, and be fed by existing particle sources and pre-accelerators. A challenging machine, the LHC will use the most advanced superconducting magnet and accelerator technologies ever employed. LHC experiments are, of course, being designed to look for theoretically predicted phenomena. However, they must also be prepared, as far as is possible, for surprises. This will require great ingenuity on the part of the physicists and engineers.
T he LHC is a remarkably versatile accelerator. It can collide proton beams with energies around 7-on-7 TeV and beam crossing points of unsurpassed brightness, providing the experiments with high interaction rates. It can also collide beams of heavy ions such as lead with a total collision energy in excess of 1,250 TeV, about thirty times higher than at the Relativistic Heavy Ion Collider (RHIC) under construction at the Brookhaven Laboratory in the US. Joint LHC/LEP operation can supply proton-electron collisions with 1.5 TeV energy, some five times higher than presently available at HERA in the DESY laboratory, Germany. The research, technical and educational potential of the LHC and its experiments is enormous.
|Last update: 14-JAN-99|