11-T Twin-Aperture $\hbox{Nb}_{3}\hbox{Sn}$ Dipole Development for LHC Upgrades

FNAL and CERN are developing a twin-aperture 11-T
$\hbox{Nb}_{3}\hbox{Sn} $
dipole suitable for installation in the LHC. This paper describes the design and parameters of the 11-T dipole developed at FNAL for the LHC upgrades in both single-aperture and twin-aperture configurations, and presents details of the constructed dipole models. Results of studies of magnet quench performance, quench protection, and magnetic measurements performed using short 1-m-long coils in the dipole mirror and single-aperture configurations are reported and discussed.