Optical functions parametrization: beta*=1540 m

We report about a method to estimate the acceptance of Roman Pot detectors at high optics using a parametrisation of the optical functions to estimate the proton coordinates at the detectors. These optical functions depend on the transverse position, on the scattering angle and on the momentum loss of the proton at the interaction point. The complete parametrization has been performed and the comparison with simulated events has been carried out showing differences of less than 50 um on the proton coordinates. We conclude that this methods can be used for the estimation of the Roman Pot detector acceptances.