Beam optics correction in the PLS-II storage ring

Abstract

LOCO (Linear Optics from Closed Orbit) is a tool to analyze linear beam-optics and search for errors in the quadrupole focusing strength. Analysis with the help of LOCO reveals these errors by fitting the measured orbit-response matrix to the model orbit-response matrix. By readjusting the currents of the quadrupole-magnet power supplies to eliminate the magnet-gradient error, we can bring the machine's optics parameter close to the design values. In this paper, we use LOCO to show how the design beam optics is restored in the PLS-II storage ring.