Further development of the sextupole dipole corrector (MSCB) magnet for the LHC

Combined sextupole dipole corrector magnets (MSCB) will be mounted in each half cell of the new Large Hadron Collider (LHC) being built at CERN. The d ipole part, used for particle orbit corrections, will be powered individual ly and is designed for low current, originally 30 A but now 55 A. The sextu pole part, used for chromaticity corrections, is connected via cold busbars in families of 12 or 13 magnets and is powered with 550 A. Several version s of this corrector magnet were tested as model magnets in order to develop the final design for the series. In the first design the coils are nested, with the dipole coil wound around the sextupole coil to obtain as short a magnet as possible, accepting the slight cross-talk between the coils due t o persistent currents, and increased saturation effects. The design has evo lved and an alternative design, in which the dipole and sextupole coils are separated, is now favored. Tests at 4.5 K and at 1.9 K were conducted to d etermine the training behavior, the field quality, and the cross-talk betwe en the windings. This paper discusses the results for the different configu rations.