Design and status of the dipole spectrometer magnet for the ALICE experiment

A large Dipole Magnet is required for the Muon Arm spectrometer of the ALICE experiment in the future LHC. The absence of constraints of symmetry and homogeneity of the magnetic field has lead to a design dominated by economical and feasibility considerations. In March 1997 the decision was taken to build a resistive dipole magnet for the muon spectrometer of the ALICE experiment. Since then design work has been pursued in JINR/Russia and at CERN. While a common concept has been adopted for the construction of the steel core, two different proposals have been made for the manufacturing technology of the excitation coils. In both cases, however, the conductor material will be aluminum. The general concept of the dipole magnet is based on a window frame return yoke, fabricated from low carbon steel sheets. The flat vertical poles follow the defined acceptance angle of 9 degree. The excitation coils are of saddle type. The coils are wound from large hollow aluminum profiles. They are cooled by pressurized demineralized water. The coil ends are located to both sides of the magnet yoke and determine the overall length of the magnet. The main flux direction in the gap is horizontal and perpendicular to the LHC beam axis. Both coil concepts and the underlying manufacturing technology are compared and the present status of the development of the magnet is described.