Beam Momentum Calibration at the LHC

The TOTEM experiment at the LHC has requested a momentum determination with an accuracy of 0.05% at 7 TeV/c to minimize the contribution of the beam momentum uncertainty to the error on the total cross section measurement. In this note three possible calibrations methods are discussed and their expected accuracies are estimated. These methods are the evaluation of the momentum from the magnetic calibration tables and the central frequency, the comparison of revolution frequencies of lead ion and proton beams and finally the option of a dedicated magnetic spectrometer.