FEL performance achieved at PAL-XFEL using a three-chicane bunch compression scheme

J Synchrotron Radiat. 2019 Jul 1;26(Pt 4):1127-1138. doi: 10.1107/S1600577519005861. Epub 2019 Jun 19.

Abstract

PAL-XFEL utilizes a three-chicane bunch compression (3-BC) scheme (the very first of its kind in operation) for free-electron laser (FEL) operation. The addition of a third bunch compressor allows for more effective mitigation of coherent synchrotron radiation during bunch compression and an increased flexibility of system configuration. Start-to-end simulations of the effects of radiofrequency jitter on the electron beam performance show that using the 3-BC scheme leads to better performance compared with the two-chicane bunch compression scheme. Together with the high performance of the linac radiofrequency system, it enables reliable operation of PAL-XFEL with unprecedented stability in terms of arrival timing, pointing and intensity; an arrival timing jitter of better than 15 fs, a transverse position jitter of smaller than 10% of the photon beam size, and an FEL intensity jitter of smaller than 5% are consistently achieved.

Keywords: arrival timing jitter; bunch compression; coherent synchrotron radiation; free-electron laser; hard X-rays; stability.