Centers & Labs

RIKEN SPring-8 Center

Beam Dynamics Team

Team Leader: Toru Hara (D.Sci.)
Toru  Hara(D.Sci.)

The team does research on generation, precise control and stabilization of brilliant electron beams on the basis of charged particle dynamics and electrodynamics. The team also does research on optimum schemes for Seeded FEL in wavelengths from soft to hard X-rays.

Main Research Field

Interdisciplinary science and engineering

Related Research Fields



  • Free-electron laser
  • Linear accelerator
  • Synchrotron radiation
  • Electro-magnet

Selected Publications

  1. Hara T et al.:
    "Two-colour hard X-ray free-electron laser with wide tunability"
    Nature Communications, vol. 4, 2919 (2013).
  2. Hara T et al..:
    "Time-interleaved multienergy acceleration for an x-ray free-electron laser facility"
    Physical Review ST-AB, vol.16, 080701 (2013).
  3. Ishikawa T et al.:
    "A compact X-ray free-electron laser emitting in the sub-angstrom region"
    Nature Photonics 6, p. 540 (2012).
  4. Hara T, Togawa K, Tanaka H.:
    "Transverse envelope analysis for accelerating relativistic electron beams in a linear accelerator as a photon source."
    NUCL INSTRUM METH A, vol.624, p.65 (2010).
  5. Togawa K, Hara T, Tanaka H.:
    "Electron-bunch compression using a dynamical nonlinearity correction for a compact x-ray free-electron laser."
    Physical Review ST-AB, vol.12, p.080706 (2009).
  6. Shintake T, Tanaka H, Hara T, Tanaka T, Togawa K et al.:
    "Stable operation of a self-amplified spontaneous-emission free-electron laser in the extremely ultraviolet region."
    Physical Review ST-AB, vol.12, p.070701 (2009).
  7. Lambert G, Hara T, Garzella D, Tanikawa T, Labat M, et al.:
    "Injection of harmonics generated in gas in a free-electron laser providing intense and coherent extreme-ultraviolet light."
    Nature Physics, vol. 4, p.296 (2008).
  8. Shintake T, Tanaka H, Hara T, Togawa K, Tanaka T, et al.:
    "A compact free-electron laser for generating coherent radiation in the extreme ultraviolet region."
    Nature Photonics vol. 2, p. 555 (2008).
  9. Hara T, Togawa K, Tanaka H.:
    Proceedings of the FEL conference 2010, Malmo, p.111 (2010).
  10. Kano Y, Hara T, Takebe H, Fukami K, Kumagai N.:
    Proceedings of the 7th Annual Meeting of Particle Accelerator Society of Japan (in Japanese), Himeji, p.558 (2010).

Lab Members

Principal Investigator

Toru Hara
Team Leader

Core Members

Kazuaki Togawa
Senior Research Scientist
Takahiro Inagaki
Senior Research Scientist
Hirokazu Maesaka
Senior Research Scientist

Contact information

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

Email: toru [at]