Progress on the superconducting magnets for the Large Hadron Collider

After a review of the proposed CERN Large Hadron Collider (LHC) project, the present design of the high-field superconducting magnets is described. One half of each standard cell for the ring of the magnet system under development consists of four ( approximately 10-m long) dipole magnets, a focusing quadrupole magnet, a tuning quadrupole, a combined sextupole/dipole corrector magnet, and a beam observation station. Only the main features of the dipole design are given. Both presently possible routes to high-field/high-current density magnets, using NbTi superconductors at superfluid helium temperatures or Nb₃Sn at 4.5 K, are summarized. Other major systems such as the vacuum chamber, proton synchrotron, and cavities are also noted. The work then presents the main aspects and the first results of the research and development program that was undertaken in close collaboration with various European industries and laboratories. Emphasis here is on the development of suitable NbTi and Nb₃Sn wires and cables, and the construction of magnet models (1-m long) and of a 9-m long twin-aperture prototype dipole.