A new PLS-II in-vacuum undulator and characterization of undulator radiation

This paper describes the result of overall studies from development to characterization of undulator radiation. After three years of upgrading, PLS-II has been operating successfully since 21st March 2012. During the upgrade, we developed and installed an in-vacuum undulator (IVU) that generates brilliant X-ray beam. The IVU with a 3 GeV electron beam generates undulator radiation up to ~ 21 keV by using 11th higher harmonic. The characterizations of the undulator radiation at an X-ray beam line in PLS-II agreed well with the simulation. Based on this performance demonstration, the in-vacuum undulator is successfully operating at PLS-II.