Magnets for the large hadron collider

CERN is finalising the design of the Large Hadron Collider (LHC), a proton-proton accelerator/collider to be installed in the existing 27 km long LEP tunnel. The principal component of the projected machine is a high-field superconducting magnet system embracing two beam pipes in common yokes and cryostats. The dipole magnets, to guide the beams in their quasi circular orbit, will provide a field of 8.65 T for a 14 TeV centre of mass energy in proton-proton collisions. The corresponding field gradient of the main focusing quadrupole magnets will be 220 T/m. To reach these high performances the magnets will be cooled by superfluid helium at 1.9 K. Dipoles and quadrupoles will be of the two-in-one type. There will be about 1300 thirteen metre long dipole, 380 three metre long quadrupoles and a large number of other superconducting magnets for correction and special purposes, for a total of about 10'000 superconducting magnetic units. The magnet R and D programme, which was started several years ago, is centred on the main dipoles and quadrupoles. Prototype short dipoles have reached the record field of 10.5 T. A general description of the system is given together with the main design features and the state of the R and D programme. (orig.)