Beam-optics analysis and periodicity restoration in the storage ring of the Pohang Light Source

Abstract

In this paper, we examine numerically and experimentally linear beam-optics distortion in the storage ring of the Pohang Light Source (PLS) and the correction of optics by using a number of quadrupole magnets installed in the storage ring. The measured orbit-response matrices were fitted to the model-response matrices to obtain beta and the dispersion functions in the storage ring. By readjusting the currents of quadrupole-magnet power supplies, we were able to successfully restore the optics parameters to values very close to the design ones. The results revealed that the power-supply current of a quadrupole magnet was off significantly by a maximum of 18%. After optics correction, the performance of the storage ring is expected to be better.