Studies of a New Optics With Intermediate Transition Energy as Alternative for High Intensity LHC Beams in the CERN SPS

The LHC injector upgrade project calls for a twofold increase in intensity of the SPS proton beam. In this paper, we present studies with a new SPS optics called Q22, which has a transition energy in between the one of the operationally used Q20 and Q26 optics. This new optics provides a compromise between the stability of Q20, due to the low transition energy, and the reduced requirements in terms of RF voltage and power in Q26. A non-linear effective model of Q22 has been extrapolated from beam based measurements and used to complement the SPS non-linear optics model. Furthermore the studies of the TMCI threshold performed so far are discussed.