BEAM BASED ALIGNMENT AT THE POHANG LIGHT SOURCE*

A beam based alignment method was adopted to re-calibrate the Beam Position Monitors (BPM) to the center of quadrupole magnets at the Pohang Light Source (PLS). We added a shunt circuit to each quadrupole magnet to control the current indepen-dently. This alignment method involves BPM readings and shunt impedance controls at the quadurpole mag-nets. This paper presents the beam based alignment control mechanism, the process, and the results.