Preliminary considerations about the injectors of the HE-LHC
  A hadron collider operating at an energy much larger than the LHC ("HE-LHC") would be a logical successor to the LHC itself, especially if its cost can be minimized by reusing a significant part of the CERN infrastructure like the existing tunnels and/or accelerators. The injector complex must however be extended to reach a beam energy of ~1.2 TeV and. in view of the time span of the HE-LHC project, the replacement of ageing accelerators can also be necessary. The main possible options are outlined together with their specificities. 
R. Garoby (CERN)
physics.acc-ph