Civil engineering for CERN1's next major particle accelerator, the Large Hadron Collider (LHC), got the green light from France last week when Prime Minister Lionel Jospin signed the decree allowing work to commence. This important landmark for the laboratory, situated on the Franco-Swiss border, comes after a long and painstaking study of the environmental impact of the project and follows Swiss approval earlier this year.
The LHC will be the world's most powerful particle accelerator allowing physicists to study the fundamental constituents of matter more closely than ever before. It will accelerate beams of protons, the nuclei of hydrogen atoms, to nearly the speed of light before smashing them together head-on. Due to switch on in 2005, the LHC has already attracted thousands of physicists from all over the world who are currently preparing their experiments. For the first time in CERN's history, the Laboratory's 19 European Member States are collaborating with other countries, Canada, India, Israel, Japan, Russia, and the United States not only on the experimental programme, but also on constructing the accelerator itself.
The 27-kilometre tunnel built for CERN's current flagship accelerator, the Large Electron-Positron collider (LEP), will house the LHC. At first glance, the civil engineering needed to accommodate the LHC in the LEP tunnel appears minor. However, it is anything but. Because of the amount of work required, contracts are being awarded in three separate packages. The only civil engineering work excluded from these packages is one of the tunnels which will carry protons from the smaller Super Proton Synchrotron accelerator to the LHC. This is being built by Switzerland as part of a special host-state contribution to the LHC project.
Civil engineering in Switzerland is already under way, but the French sites for the LHC have not been idle in the wait for government approval. A collaboration between CERN and the regional directorate for cultural affairs has allowed archaeologists to undertake preliminary digs at a Roman site adjacent to one of the LHC's experimental areas. Their findings have allowed them to piece together a picture of life in the area some 1700 years ago. Mr Jospin's signature gives CERN the go ahead to take this voyage back in time even further. As the civil engineers dig down through the foothills of the Jura mountains, they will be cutting through terrain which formed in two phases about 66.4 million years ago and between 5.3 and 1.6 million years ago. The rock itself dates from about 208 to 144 million years, and by recreating the conditions of the big bang the LHC's collisions will take physicists back almost to the beginning of time itself.