Dynamic Effects on Chromaticity for the LHC beam cycle in the SPS

During the energy ramp of the SPS the chromaticity is subject to significant dynamic effects. Sextupolar field errors due to eddy currents and remanent fields lead to beam momentum and ramp rate dependent corrections. Detailled measurements on the LHC beam cycle have been used to verify the modelling and reproducibility the chromaticity corrections. Large deviations were found between the presently used model and the measured chromaticity trims. An improved empirical model is suggested.