Non-Linear Ring Model Calibration with Frequency Analysis of Betatron Oscillations

A precise model of an accelerator ring is crucial to achieve ultimate performance both in synchrotron light sources and high energy synchrotrons. Algorithms have been developed to calibrate the linear model of the ring. They have been successfully applied experimentally to determine and correct the linear optics of the machine. More recently the Frequency Map Analysis has been used to model also the non-linear optics. We propose here a technique based on the fit of non-linear spectral lines to recover the non-linear driving terms and to compensate the non-linear field errors around the ring.