Quench Protection Study of a Single-Aperture 11 T $\hbox {Nb}_{3}\hbox {Sn}$ Demonstrator Dipole for LHC Upgrades

The planned upgrade of the Large Hadron Collider (LHC) collimation system will include installation of additional collimators in the dispersion suppressor areas. The longitudinal space for the collimators could be provided by replacing 15-m-long 8.33 T NbTi LHC main dipoles with shorter 11 T Nb₃Sn dipoles compatible with the LHC lattice and main systems. FNAL and CERN have started a joint program with the goal of building a 5.5-m-long twin-aperture Nb₃Sn dipole prototype suitable for installation in the LHC. The first step of this program is the development of a 2-m-long single-aperture demonstrator dipole with a nominal field of 11 T at the LHC nominal current of 11.85 kA. This paper summarizes the results of quench protection studies of 11 T dipoles performed using the single-aperture Nb₃Sn demonstrator.