Abstract
The Pohang Light Source (PLS) storage ring is a synchrotron light source that has been operated using a 2.5 GeV full energy injection from a linac since October 2002. It is necessary to search for betatron tunes that can realize large dynamic apertures in a 2.5 GeV full energy injection. Accordingly, we investigated dependence of dynamic aperture on the betatron tune to obtain large dynamic apertures in the storage ring by a simulation method. We examined dynamic apertures by a tune survey within a specified tune space with and without machine errors. It is also shown how large are the dynamic apertures in the storage ring recovered are after the correction of a closed orbit distortion. The operating tune is examined from the viewpoint of dynamic apertures obtained by a tune survey.