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TY - CONF AU - Kim, S.H. AU - Kang, H.-S. AU - Kim, K.H. AU - Lee, H.-S. AU - Min, C.-K. AU - Park, S.S. AU - Park, Y.J. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Stability and Reliability Issues of PAL-XFEL Modulator J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL) employs 51 units of the pulse modulator in order to obtain the 10 GeV electron beam, which drive one X-band to linearize and 50 S-band klystrons. The PAL-XFEL requires very tight control of the klystron RF phase jitter 0.03-degree for S-band RF, 0.1-degree for X-band RF and the beam voltage stability of below 50 ppm. The RF phase jitter is directly related to the amplitude stability of modulator output pulses. There are several factors to satisfy the stability and reliability for the PAL-XFEL modulator. The largest sources of pulse-to-pulse instability are a current charging power supply (CCPS) for PFN charging, a thyratron switch, and a klystron focusing magnet power supply (MPS). In this paper, the operation and debugging results of those devices are described. PB - JACoW Publishing CP - Geneva, Switzerland SP - 4096 EP - 4099 KW - FEL KW - klystron KW - operation KW - power-supply KW - electron DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-THPRB117 UR - http://jacow.org/ipac2019/papers/thprb117.pdf ER -