The possibility of polarisation in the LHeC ring-ring scenario

A proposal to add 60-GeV electron and positron beams to the LHC at CERN (LHeC) is currently being prepared. The provision of electron and positron longitudinal polarisation is an important component of the proposal and we are examining the feasibility of Sokolov-Ternov self-polarisation at energies up to 60 GeV in a storage ring in the LHC tunnel. But at this energy the attainable polarisation can be very strongly limited by depolarising effects. This paper summarises first calculations of the attainable polarisation including estimates of the efficacy of Siberian Snakes for weakening synchrotron sideband resonances