Lawrence Berkeley National Laboratory

LOCO is a code for analysis of the linear optics in a storage ring based on the closed orbit response to steering magnets. The analysis provides information on focusing errors, BPM gain and rotation errors,and local coupling. Here, we report the results of an application of LOCO to the KEK-ATF. Although the analysis appears to have provided useful information on the optics of the machine, it appears that one of the main aims of the study to reduce the vertical emittance by correcting the local coupling was not successful, and we discuss some possible reasons for this.