Centers & Labs

RIKEN SPring-8 Center

FEL Physics Team

Team Leader: Takashi Tanaka (D.Eng.)
Takashi  Tanaka(D.Eng.)

FEL physics team is in charge of development of devices called undulators, which induce interaction between radiation and electron beam to realize x-ray lasing. In addition, theoretical research and new XFEL scheme are explored to futher upgrade the laser performance of SACLA.

Main Research Field

Interdisciplinary science and engineering

Related Research Fields

Mathematical and physical sciences / Engineering


  • free electron laser
  • synchrotron radiation
  • undulator
  • simulation
  • permanent magnet

Selected Publications

  1. Y. Kida, R. Kinjo and T. Tanaka:
    "Synthesizing high-order harmonics to generate a sub-cycle pulse in free-electron lasers"
    Applied Physics Letters 109, 151107 (2016)
  2. T. Bizen et al.:
    "Radiation-induced magnetization reversal causing a large flux loss in undulator permanent magnets"
    Scientific Reports 6, 37937 (2016)
  3. T. Tanaka et al.:
    "Using irregularly spaced current peaks to generate an isolated attosecond X-ray pulse in free-electron lasers"
    Journal of Synchrotron Radiation 23, 1273 (2016)
  4. T. Tanaka:
    "Reducing the group velocity of coherent radiation for upconverting the single-cycle electron density modulation"
    Applied Physics Letters 108, 061106 (2016)
  5. T. Tanaka:
    "SIMPLEX: simulator and postprocessor for free-electron laser experiments"
    Journal of Synchrotron Radiation 22, 1319 (2015)
  6. T. Tanaka:
    "Proposal to generate an isolated monocycle X-ray pulse by counteracting the slippage effect in free-electron lasers"
    Physical Review. Letters 114, 044801 (2015)
  7. T. Hara, Y. Inubushi, T. Katayama, T. Sato, H. Tanaka, T. Tanaka et al.
    "Two-colour hard X-ray free-electron laser with wide tunability"
    Nature Comm., 4 (2013) 2919
  8. K. Tamasaku, M. Nagasono, H. Iwayama, E. Shigemasa, Y. Inubushi, T. Tanaka et al.
    "Double Core-Hole Creation by Sequential Attosecond Photoionization"
    Phys. Rev. Lett., 111 (2013) 043001
  9. T. Tanaka
    "Proposal for a Pulse-Compression Scheme in X-Ray Free-Electron Lasers to Generate a Multiterawatt, Attosecond X-Ray Pulse"
    Phys. Rev. Lett., 110 (2013) 084801
  10. H. Yumoto, H. Mimura, T. Koyama, S. Matsuyama, K. Tono, et al.
    "Focusing of X-ray free electron laser pulses with reflective optics"
    Nature Photon., 7 (2013) 43

Lab Members

Principal Investigator

Takashi Tanaka
Team Leader

Core Members

Ryota Kinjo
Research Scientist

Contact Information

1-1-1 Kouto, Sayo-cho
Sayo-gun, Hyogo
679-5148 Japan

Email: ztanaka [at]

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