Development of Radiation Resistant Superconducting Corrector Magnets for LHC Upgrade

Two prototype superconducting corrector magnets, a sextupole and an octupole, have been designed and fabricated by CIEMAT during the preparatory phase for the Large Hadron Collider (LHC) luminosity upgrade, in the framework of the SLHC project. These magnets will be grouped with other correctors in a dedicated cryo-assembly, placed in the LHC insertion regions. The magnets shall be designed to withstand radiation levels up to 10 MGy. Therefore, the nominal aperture will be increased to 140 mm to include a 10-mm-thick steel shielding, and all materials must be radiation resistant. The sextupole has been produced with conventional materials but radiation-resistant ones have been used for the octupole, like polyimide insulated wire and cyanate-ester resin. The nominal integrated strength of the sextupole is 0.055 T · m (0.035 T · m for the octupole) at 40 mm reference radius and overall mechanical length is 160 mm (180 mm for octupole). Due to the moderate peak field, a superferric design is preferred, which also allows placing the coils further away from the aperture. Fabrication techniques and test results are described.