S-band Traveling-Wave Deflecting Structures for the PAL-XFEL

We designed a 20-MV S-band traveling-wave deflecting structure to measure the bunch length of the electron beams for the PAL-XFEL. Since the start of commissioning of all RF systems of the PAL-XFEL on 12 April 2016, two out of three fabricated structures are currently being operated; one each in the hard X-ray and the soft X-ray branches. These deflecting structures were carefully tuned by using a 4-m-long nodal phase scanner in a precisely temperature and humidity controlled cleanroom considering the phase predictions calculated using RF field solvers. We carried out RF conditioning and beam commissioning with highly-stable high-power S-band RF systems and an EPICS-based control system. We briefly present our design of S-band deflecting structure and discuss the test results, including the results of the RF and the beam measurements.