DYNAMIC APERTURE OF ELECTRON STORAGE-RINGS WITH NONINTERLEAVED SEXTUPOLES

A detailed study of a dynamic aperture is given for electron storage rings with noninterleaved sextupole magnets. As a result of a cancellation of major transverse nonlinearities of sextupoles by -I transformers, other tiny terms such as fringe fields of quadrupoles and kinematical terms of drift spaces come to limit the transverse dynamic aperture. Results for transverse aperture in simulations can be explained by a simple one-dimensional model including these terms. In the longitudinal direction, a modulation of linear betatron motion by synchrotron oscillation is investigated as the source of the aperture limit.