Computation of nonlinear one-turn maps from measurement with model-independent analysis

It is desirable to determine the nonlinear transformation maps, especially the one-turn map, of a storage ring from measured BPM data for nonlinear analysis in order to improve the machine performance. However, the accuracy of detecting the weak signals from nonlinear effects is often limited by the available BPM resolution. With the recent development of Model-Independent Analysis methods, which can significantly reduce BPM random noise via statistical analysis, it is possible to more accurately determine the nonlinear maps from measured data by using a large number of BPMs. Computational techniques and some simulation results for PEP-II are presented.