Director Hiroyuki Hama

Research Center for ELectron PHoton Science (ELPH), former Laboratory for Nuclear Science (LNS) was established in 1966 attached to Faculty of Science, Tohoku University. In 1967, a large-scale 300MeV electron linac was completed, and the 300MeV linac commenced to provide the beams to not only nuclear physics but many scientific fields. In addition to the higher beam energy, the 300MeV linac had been operated at a tremendous repetition rate such as 300pps, which is still marvelous for the current linac technology trend. The 300MeV linac played an important role in a new era of nuclear physics driven by high-energy electron beam electron beam, and left a number of significant results such as a study of giant resonance in deformed nuclei via electron inelastic scattering. Furthermore a pulsed-neutron from a dense target irradiated by the high-power electron beam was developed for solid-state physics and other related science, which was conducted by the first director of the Laboratory, Dr. Motoharu Kimura. This historical 300MeV linac is no longer here (the actual maximum energy was ~ 220MeV due to deterioration of accelerating structure shunt impedance in its closing years). Major components of the 300MeV suffered serious damages due to the Great East Japan Earthquake on March 11, 2011. Since there was no technical support for the 44-year-old linac, recovering whole function was impossible any longer. Nowadays superconducting technology has been developed for high average power electron beam, so that the high-repetition normal conducting linac seems to be left behind. This means it may take a huge budget to re-construct a 300Hz - 300MeV linac. It was very difficult task to recover the functions of 300MeV linac. Consequently we have decided to separate major functions of the linac, i.e. production of radioisotopes and beam injection into a 1.2GeV booster synchrotron. Among five 25MW-klystron modulators, two adequate modulators were recovered as main power sources for a 300Hz - 60MeV linac. Other usable components and devices in the old linac have been stocked for possible malfunctions in the near future. A beam transport line into the 1st experimental room where there is a target station for the radioisotope production was also improved by introducing a new dispersive section and a dispersion-free beam line. The memorial linac was revived as an extremely high beam power linac dedicated to the radioisotope production. Accordingly handling of the high-power beam has been greatly improved, so that the stable beam can be provided to users in a short tuning time. Meanwhile, a 1.2GeV booster synchrotron, the so-called STB-ring, was also recovered and reincarnated as a 1.3GeV booster-storage ring (BST-ring) by introducing high-performance synchrotron tracking power supplies. Furthermore the BST ring is now able to store the high beam current more than 100mA theoretically because of replacing quadrupole magnets with sextupole-quadrupole combined magnets to cure the head-tail instability. A 90MeV injector linac was newly constructed in which an originally developed thermionic RF gun was introduced for reducing the linac cost. The role of old 300MeV linac is then distributed to the high-power linac and the injector linac so that parallel operation of two linacs is indeed possible. Detail of recovering from the disaster was reported in an issue “ELPH annual report 2011 – 2013”. In 2014, reform of the research building was completed. This might be very much surprising for ones who know it used to be. The building looks fine and equips a new conference hall whose seating capacity is more than 100 people. In addition, utilities in the facility, such as electricity receiving and transforming station, monitoring system for radiation safety,reservoir pool for polluted water and etc, were fixed and mostly improved. In addition to these facts, the alteration of the 300MeV linac, a symbol in the long history of ELPH and LNS, implies an opening of new era of the Laboratory. Four years have already passed since the big earthquake and tsunami attacked. The scars left by the tsunami were still visible in every quarter. We should not forget contribution for the local area alongside of recovering our research activity. In 2014, we have embarrassed particularly by the steep rise of electricity price. However we are going to reverse the situation and let us be substantial parts of the next generation of the Laboratory. We sincerely ask facility users and related scientific field communities for strong supports and cooperation.

April, 2015 Director Hiroyuki Hama








  • 2016 The 50th anniversary of the foundation.
  • Apr 2015 Collaborative research division “Condensed Matter Nuclear Reaction” established.
  • Jul 2014 Research building renovated and the Mikamine Hall completed.
  • Dec 2013 Operation resumed after recovery from the Great East Japan Earthquake.
  • Apr 2011 Approved as a Joint Usage/Research Center for Electron Photon Science.
  • Mar 2011 Operation suspended due to damages by the Great East Japan Earthquake.
  • Mar 2010 “Accelerator-based Light Source Building” completed.
  • Dec 2009 Reorganized as “Research Center for Electron Photon Science”.
  • Sep 2009 Electromagnetic calorimeter “FOREST” completed in the Gamma-ray Irradiation Room.
  • Feb 2008 “High-frequency Power Source Building” completed.
  • Sep 2006 Magnetic electrometer “NKS2” completed in the Second Experimental Room.
  • May 2006 Electron-Positron test beam line operation started.
  • Jul 2002 GeV Gamma-ray Irradiation building completed and started Hadron experiments.
  • 1998 Organized as adjunct facility of Graduate School of Science.
  • 1997 1.2 GeV Stretcher Booster Ring completed.
  • 1988 World’s first observed coherent emission.
  • 1982 150 MeV Pulse Stretcher completed.
  • 1971 Pulse neutron source developed.
  • 1967 300 MeV Electron LINAC completed.
  • 1966 Established as an on-campus shared-use facility in nuclear physics.




As of April 2015

Director :  Professor Hiroyuki Hama




August 2015 ※e-mail address: ※Telephone number: +81- 22-743-####

Academic staff list (ELPH)

Name Title Research field e-mail tel
Hiroyuki HAMA Professor Director of ELPH Beam physics/Accelerator Science hama 3432
Hajime SHIMIZU Professor Quark Nuclear Physics hshimizu 3423
Toshimi SUDA Professor Exotic Nuclear Physics suda 3420
Yasuhiro IWAMURA Professor Condensed Matter Nuclear Reaction iwamura 3462
Shigeru KASHIWAGI Assoc. Prof. Beam physics/Accelerator Science kashiwagi 3434
Hidetoshi KIKUNAGA Assoc. Prof. Radiation Chemistry kikunaga 3425
Fujio HINODE Assoc. Prof. Beam physics/Accelerator Science hinode 3424
Norihito MURAMATSU Assoc. Prof. Quark Nuclear Physics mura 3416
Takehiko ITOH Assoc. Prof. Condensed Matter Nuclear Reaction itoh 3426
Takatsugu ISHIKAWA Assis. Prof. Quark Nuclear Physics ishikawa 3433
Kyo TSUKADA Assis. Prof. Exotic Nuclear Physics tsukada 3418
Manabu MIYABE Assis. Prof. Quark Nuclear Physics miyabe 3435
Toshiya MUTO Assis. Prof. Beam physics/Accelerator Science muto 3429
Atsushi TOKIYASU Assis. Prof. Quark Nuclear Physics tokiyasu 3422
Hayato IKEDA Assis. Prof. Radiation Chemistry    
Yuki HONDA Assis. Prof. Exotic Nuclear Physics honda 3417
Yuta SADA Assis. Prof. Quark Nuclear Physics sada  
Jirohta KASAGI Research Prof. Nuclear Physics, Condensed Matter Nuclear Reaction kasagi 3414
Hajime SHIMIZU Research Prof. Quark Nuclear Physics hshimizu 3414
Tadaaki TAMAE Research Prof. Exotic Nuclear Physics tamae 3418

Academic staff list (Tohoku Univ.)

Name Affiliation /  Titele Research fields
Hirokazu TAMURA Graduate school of Science, Department of physics, Professor Experimental Nuclear physics group
Satoshi NAKAMURA Graduate school of Science, Department of physics, Professor Experimental Nuclear Physics group
Masashi KANETA Graduate school of Science, Department of physics, Assis. Professor  
Kouichi HAGINO Graduate school of Science, Department of physics, Assoc. Professor Nuclear Theory
Yasushi KINO Graduate school of Science, Department of chemistry, Assoc. Professor Radiation Chemistry
Nobuyuki UOZUMI Graduate school of Engineering, Department of physics, Professor Biomolecular Engineering
Tetsuo TANIUCHI The Frontier Research Institute for Interdisciplinary Sciences (FRIS) Laser and Nonlinear Photonics

Technical Staff

Name e-mail tel
Ken'ichi NANBU nanbu 3431
Ikurou NAGASAWA nagasawa 3431
Ken TAKAHASHI ken_takahashi 3431
Ken KANOMATA kanomata 3431
Koutaro SHIBATA shibata 3431
Yoshinobu SHIBASAKI shibasak 3453


Name 学年 所属グループ e-mail tel
Hirotoshi SAITO D3 Beam physics/Accelerator Science hsaito 3422
Taihei AOYAGI D1 Exotic Nuclear Physics aoyagi  
Chihiro YOSHIDA D1 Quark Nuclear Physics yoshida  
Shota TAKAYAMA M2 Exotic Nuclear Physics takayama  
Masahiro OKABE M2 Quark Nuclear Physics okabe  
Nozomu MORITA M2 Beam physics/Accelerator Science morita  
Hiroki YAMADA M2 Beam physics/Accelerator Science yamada  
Masahiro TAKEYA M2 Condensed Matter Nuclear Reaction takeya  
Hikari WAUKE M2 Exotic Nuclear Physics wauke  
Yuto ISHIZUKI M1   ishizuki  
Jumpei TAKAHASHI M1   jtakahashi  
Daisuke TAKI M1   taki  
Kento TERADA M1   terada  
Hajime SAITO M1   hasaito  
Masato TSURUTA M1   tsuruta  
Ryota NISHIKAWA B4   rnishikawa  
Kazuya NOBATA B4   nobata  


Name e-mail tel
Office kakurike @ 3400
Takemitsu ABE ave @ 3412

Administration Office (Radiation Safety Office)

Name e-mail 電話
Administration Office kanri @ 3411
Administrative Assistant (Yumi SUGAWARA) yumi @ 1140



High intensity electron linac

High intensity electron linac








BST ring

BST ring








Injector for BST

Injector for BST








Chemistry Lab. (#3 experimental Lab.)


































































Accelerators and Beam properties

In ELPH, the electron and photon beam lines are provided for nuclear physics experiments and a radioactive isotope production. (Present Configuration (2015))

High intensity electron linac

High intensity electron linac
The 300 MeV electron linear accelerator had been constructed in 1967. In the Great East Japan Earthquake (March 11, 2011), serious damages was inflicted on this linac and a low energy part of the linac was reconstructed as a high intensity electron linac. The linac consists of 90 keV thermionic cathode gun, a buncher section and eight 1m-long s-band accelerating structures. Maximum energy of the linac is 70 MeV without beam loading. The linac is operated with 300 Hz repetition rate and a peak current in macropulse is approximately 100 mA with 3 micro-sec pulse duration. The average beam current is about 100 micro-Ampere. This high current electron beam is used for radio isotope production by photonuclear reactions.
Linac Energy Modulator Repetition Macropulse Peak Current Macropulse Duration Average Current
50 MeV 300 Hz 〜130 mA 3.0 µs 120 µA
30 MeV 300 Hz 〜100 mA 3.0 µs 90 µA

Injector linac for BST

Injector linac for BST
Injector linac for the Booster synchrotron ring.
Compact electron linac had been constructed as the injector for the booster synchrotron in 2012. The injector consists of a thermionic rf-gun, an alpha magnet, two s-band 3m-long accelerating structures, and transport line to the booster synchrotron. The maximum energy of injector is 90 MeV with beam loading. This linac has two beam lines for beam diagnostics, one is straight line and the other is 90 degree beam line with dispersion section.

1.3 GeV Booster-STorage ring (BST)

Newly installed combined function magnet.  It looks like an ordinary quadrupole magnet but has a special pole-face shape to generate the sextupole component, and thus the chromaticity correction can be accomplished with these magnets by introducing the dispersion function to the magnet location.
BST ring. The ring circumference is 50 m, and eight dipole magnets (blue pieces) deflect the electrons so as to guide the electron beam, while the focusing magnets (orange and red magnets) are used to keep the electrons circulating inside the vacuum chamber.

BST is an electron synchrotron which accelerates the electrons injected from the injector linac up to 1.3 GeV in maximum. The required energy to accelerate and store the electron beam is supplied by a 500 MHz rf cavity. By inserting a very fine carbon wire to the beam orbit of circulating electrons after the acceleration, high energy gamma rays are generated via bremsstrahlung. Two beam lines are operational to utilize such gamma rays. In a typical operation pattern, beam acceleration is immediately started just after the injection and finished within ~2 sec., and then stored electrons with ring current of 10~30 mA are consumed to generate the gamma rays over a duration of about 10~40 sec. Currently available operation energy is 1.3, 1.0 and 0.8 GeV, and typical ring current is ~15 mA.

Injection Beam Energy Injection Repetition Ring Top Energy Storage Beam Current
90 MeV ~0.05 Hz (typ.) 0.8~1.3 GeV ~30 mA

Tagged photon beamline

The BST ring has two beamlines providing tagged photons. The typical properties of the tagged photon beams are summarized in the table:
Beam line Energy Range
(Rint Energy: 1.3 GeV)
# of Bins Intensity Duty
BST-Tagger-I 0.8 ~ 1.26 GeV 160 TBC ~60% (NKS2)
BST-Tagger-II 0.9 ~ 1.25 GeV 116 TBC ~50% (FOREST)

Photon beamline I

The photons are designed to be tagged with energies of 62%~98% with respect to the circulating electron energy of the BST ring. The number of tagging channels are 160. The details of the photon beam properties are under investigation.

Please contact to Dr. Hiroki Kanda (mail:

Photon beamline II

The photons are designed to be tagged with energies of 62%~96% with respect to the circulating electron energy of the BST ring. The duty facto is approximately 50% (stable photon beam can be obtained for 8.5 s out of a 17 s cycle). The number of tagging channels are 116. The details of the photon beam properties are under investigation. Information before The Great East Japan Earthquake (March 11, 2011) can be obtained in a reference "The second GeV tagged photon beamline at ELPH"

Reference: T. Ishikawa et al., Nucl. Instr. and Meth. A 622, 1 (2010).

Please contact to Dr. Takatsugu Ishikawa (mail:

Positron/electron beamlines for testing detectors

The positrons and electrons, which are produced at a metal plate in front of the bending magnet RTAGX by the photon beam, are provided at three beamlines in the GeV-γ experimental hall. The positrons and electrons are momentum-analyzed with RTAGX, and the energy spread of them is approximately 0.5% . The beam profile and intensity depend on the beam energy, and the diameter of the beam is roughly 20 mm, the intensity is roughly a few kHz. The positrons (or electrons) at the -30 deg beamline can be focused with a triplet quadrupole magnets thanks to a KEK cooperation. The polarity of the magnets can be changed. The details of the photon beam properties after the earthquake are under investigation. Information before can be obtained in a reference "A detailed test of a BSO calorimeter with 100-800 MeV positrons",

Reference: T. Ishikawa et al., Nucl. Instr. and Meth. A 694, 348 (2012).
Beam Beam line Maximum beam energy
Positron / Electron ± 30 deg ~840 MeV
Positron -23 deg ~1000 MeV
Please contact to Dr. Takatsugu Ishikawa (mail: