Abstract

The hard X-ray free-electron laser at the Pohang Accelerator Laboratory (PAL-XFEL) in the Republic of Korea achieved saturation of a 0.144 nm free-electron laser beam on 27 November 2016, making it the third hard X-ray free-electron laser in the world, following the demonstrations of the Linac Coherent Light Source (LCLS) and the SPring-8 Angstrom Compact Free Electron Laser (SACLA). The use of electron-beam-based alignment incorporating undulator radiation spectrum analysis has allowed reliable operation of PAL-XFEL with unprecedented temporal stability and dispersion-free orbits. In particular, a timing jitter of just 20 fs for the free-electron laser photon beam is consistently achieved due to the use of a state-of-the-art design of the electron linear accelerator and electron-beam-based alignment. The low timing jitter of the electron beam makes it possible to observe Bi(111) phonon dynamics without the need for timing-jitter correction, indicating that PAL-XFEL will be an extremely useful tool for hard X-ray time-resolved experiments.

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Acknowledgements

The authors thank K.J. Kim, P. Emma, Z. Huang, P. Krejcik, A. Young, S. Hoobler, C. Xu, T. Straumann, K. Kim, Y. Ding, F. Zhou, D. Ratner, T. Raubenheimer, J. Wu, J. Pflueger and H. Matsumoto for their help. The authors also thank S.L. Cho for providing Bi thin-film samples and H. Loos and J. Loos for their contribution to the PAL-XFEL commissioning. The authors acknowledge the support of the Ministry of Science and ICT of Korea.

Author information

Affiliations

  1. Pohang Accelerator Laboratory, Pohang, Gyeongbuk, 37673, Republic of Korea

    • Heung-Sik Kang
    • , Chang-Ki Min
    • , Hoon Heo
    • , Changbum Kim
    • , Haeryong Yang
    • , Gyujin Kim
    • , Inhyuk Nam
    • , Soung Youl Baek
    • , Hyo-Jin Choi
    • , Geonyeong Mun
    • , Byoung Ryul Park
    • , Young Jin Suh
    • , Dong Cheol Shin
    • , Jinyul Hu
    • , Juho Hong
    • , Seonghoon Jung
    • , Sang-Hee Kim
    • , KwangHoon Kim
    • , Donghyun Na
    • , Soung Soo Park
    • , Yong Jung Park
    • , Jang-Hui Han
    • , Young Gyu Jung
    • , Seong Hun Jeong
    • , Hong Gi Lee
    • , Sangbong Lee
    • , Sojeong Lee
    • , Woul-Woo Lee
    • , Bonggi Oh
    • , Hyung Suck Suh
    • , Yong Woon Parc
    • , Sung-Ju Park
    • , Min Ho Kim
    • , Nam-Suk Jung
    • , Young-Chan Kim
    • , Mong-Soo Lee
    • , Bong-Ho Lee
    • , Chi-Won Sung
    • , Ik-Su Mok
    • , Jung-Moo Yang
    • , Chae-Soon Lee
    • , Hocheol Shin
    • , Ji Hwa Kim
    • , Yongsam Kim
    • , Jae Hyuk Lee
    • , Sang-Youn Park
    • , Jangwoo Kim
    • , Jaeku Park
    • , Intae Eom
    • , Seungyu Rah
    • , Sunam Kim
    • , Ki Hyun Nam
    • , Jaehyun Park
    • , Jaehun Park
    • , Sangsoo Kim
    • , Soonam Kwon
    • , Sang Han Park
    • , Kyung Sook Kim
    • , Hyojung Hyun
    • , Seung Nam Kim
    • , Seonghan Kim
    • , Sun-min Hwang
    • , Myong Jin Kim
    • , Chae-yong Lim
    • , Chung-Jong Yu
    • , Bong-Soo Kim
    • , Tai-Hee Kang
    • , Kwang-Woo Kim
    • , Seung-Hwan Kim
    • , Hee-Seock Lee
    • , Heung-Soo Lee
    • , Ki-Hyeon Park
    • , Tae-Yeong Koo
    •  & Dong-Eon Kim
  2. Department of Physics, POSTECH, Pohang, Gyeongbuk, 37673, Republic of Korea

    • In Soo Ko

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Contributions

All authors designed, constructed and tested the accelerator and X-ray systems, performed the experiments and analysed the data. I.S.Ko was the PAL-XFEL project director.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Heung-Sik Kang.