h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Hello,

this is areally goor article about particle accelerators. I appreciate it very much. But I just found some small details I would licke to comment on. The first one concerning LEP at CERN. It is true that LEP was designed to accelerate electrons and positrons to energies of 50 GeV but actually they are running at 104 GeV after some upgrades. As the Tevatron at FNAL LEP has two beams colliding at the experiments thus producing events with 208 GeV energy in the cernter of mass system.

The reason why FNAL got so much higher energies for their particles is that they use protons which have about 2000 times the mass of the electron. Therefore the trajectories of protons are much easyer to bend to a smaller radius resulting in higher energies. (The SPS at CERN produces 450GeV protons in a ring with only 7 km circumference.)

At the end of this year LEP will finish its operation and give its tunnel to the LHC project. Then a proton storage ring will be installes in the 27 km tunnel which will produce two beams of 7 TeV each. So in theory there is a center of mass energy of 14 TeV available. But as the protons are made up of several quarks and gluons the single events wil expose much lower energies.

Best regards,

R146533

Thanks very much indeed for this. And welcome to h2g2. This kind of forum response is *exactly* the kind of thing that brings a big smile to all our faces here at h2g2 Thanks once again!