Beam-size measurements by using a synchrotron radiation interferometer

The synchrotron-radiation interferometer has been employed to measure the beam size in the storage ring at the 2.5 GeV Pohang Light Source [PLS]. We discuss the optical system of the interferometer and analysis methods to measure the beam size. The PLS has used a Min/Max method to measure the beam size in the ring. In our studies, we also investigated ways in which to optimize the measured results on the beam sizes in the vertical and the horizontal directions by using fitting methods with both Mathematica and Root. We examined the variations in the background by passing time and their effects on the measured beam sizes. In this paper, we present methods for analyzing the measured data that result in improvement the measurement of the beam size in the PLS.