Author: Kim, G.
Paper Title Page
0.1-nm FEL Lasing of PAL-XFEL  
  • H.-S. Kang, H. Heo, C. Kim, G. Kim, C.-K. Min, H. Yang
    PAL, Pohang, Kyungbuk, Republic of Korea
  The hard X-ray free electron laser at Pohang Accelerator Laboratory (PAL-XFEL) achieved saturation of a 0.144-nm free electron laser (FEL) beam on November 27, 2016, making it the third hard X-ray FEL in the world, following LCLS in 2009 and SACLA in 2011. On February 2, 2017, a saturated 1.52-nm FEL beam was also achieved in the soft X-ray FEL line with an electron beam energy of 3.0 GeV. Finally, saturation of a 0.104-nm FEL beam was achieved on March 16, 2017 using an electron beam energy of 9.47 GeV and K = 1.87. In this paper we present the commissioning result of PAL-XFEL as well as the beamline commissioning results.  
slides icon Slides MOC01 [7.016 MB]  
Demonstration of Harmonic Lasing Self-Seeded Mode for Soft X-Rays Down to 1nm at PAL-XFEL  
  • I.H. Nam, H. Heo, H.-S. Kang, C. Kim, G. Kim, C.-K. Min, H. Yang
    PAL, Pohang, Kyungbuk, Republic of Korea
  Harmonic lasing is a promising way to provide the beams that can be brilliant, stable and narrow-band. We demonstrate the 3rd harmonic lasing operation in the current configuration with gap-tunable planar hybrid type undulators at soft X-ray beam line at PAL-XFEL. In order to suppress the fundamental resonant radiation, we used a set of phase shifters for optimal condition. This new operation mode can improve the spectral brightness compare to Self-Amplified Spontaneous emission (SASE) mode. In this paper, we report the results of these studies of the harmonic lasing mode for soft X-ray in the wavelength down to 1 nm with the electron beam energy of 3 GeV at PAL-XFEL.  
TUP058 Slippage-Enhanced SASE FEL 1
  • J. Wu, A. Brachmann, K. Fang, A. Marinelli, C. Pellegrini, T.O. Raubenheimer, C.-Y. Tsai, C. Yang, M. Yoon, G. Zhou
    SLAC, Menlo Park, California, USA
  • H.-S. Kang, G. Kim, I.H. Nam
    PAL, Pohang, Republic of Korea
  • B. Yang
    University of Texas at Arlington, Arlington, USA
  Funding: The work was supported by the US Department of Energy (DOE) under contract DE-AC02-76SF00515 and the US DOE Office of Science Early Career Research Program grant FWP-2013-SLAC-100164.
High-brightness XFEL is demanding for many users, in particular for certain types of imaging applications. Seeded FELs including self-seeding XFELs were successfully demonstrated. Alternative approaches by enhancing slippage between the x-ray pulse and the electron bunch were also demonstrated. This class of Slippage-enhanced SASE (SeSASE) schemes can be unique for FEL spectral range between 1.5 keV to 4 keV where neither grating-based soft x-ray self-seeding nor crystal-based hard x-ray self-seeding can easily access. SeSASE can provide high-brightness XFEL for high repetition rate machines not suffering from heat load on the crystal monochromator. We report start-to-end simulation results for LCLS-II project and PAL-XFEL project with study on tolerance. Performance comparison between SaSASE FEL and self-seeding FEL in the overlapping frequency range is also presented.