High power and high precision pattern power supply of kicker magnet at SACLA

At the XFEL facility SACLA a beam switching system composed of a pulsed kicker magnet and a DC separator has been installed to perform pulse-by-pulse XFEL switching operations over two XFEL beamlines (BL2 and BL3). However, CSR effects at a dogleg beam transport to BL2 with a deflecting angle of 3 degrees significantly limited the peak current of the electron beam. In order to cancel out the CSR effects, new beam optics, which is more symmetric in terms of the deflecting field distribution, is introduced to the dogleg. Here, a deflecting angle of the kicker magnet working as the first bending magnet in the dogleg is increased from 0.5 to 1.5 degrees. To drive the kicker magnet, a high-power pattern power supply, whose maximum output power is 0.3 MW (299 A and 1 kV) with a current stability of 10 ppm (peak-to-peak), has been developed using SiC MOSFETs as switching elements. This power supply can generate bipolar trapezoidal current waveforms at 60 Hz, and the amplitude and polarity of each waveform are controllable within the required current stability from a pulse to a pulse depending on a beam energy and a destination. This presentation reports the design overview and obtained performance of the developed power supply together with beam commissioning results of the new pulse-by-pulse switching system. (author)