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
Academic staff list (ELPH)
|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|
|Jirohta KASAGI||Research Prof.||Nuclear Physics, Condensed Matter Nuclear Reaction||kasagi||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|
|Kazushige MAEDA||Graduate school of Science, Department of physics, Professor||Intermediate Energy Nuclear Physics group|
|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|
|Yusuke TSUCHIKAWA||D3||Quark Nuclear Physics||tsuchikawa||3435|
|Ryuji YAMAZAKI||D3||Quark Nuclear Physics||ryama||3433|
|Yuki HONDA||D3||Quark Nuclear Physics||honda||3435|
|Yuji MATSUMURA||D1||Quark Nuclear Physics||matumura||3422|
|Teruaki TSURU||M2||Exotic Nuclear Physics||tsuru||3414|
|Ken'ichiro SHIRAISHI||M2||Quark Nuclear Physics||siraisi||3422|
|Satoshi KIDO||M2||Quark Nuclear Physics||kido||3422|
|Hirotoshi SAITO||M2||Beam physics/Accelerator Science||hsaito||3422|
|Yosuke MORIYA||M2||Exotic Nuclear Physics||moriya||3422|
|Taro ABE||M1||Beam physics/Accelerator Science||abe||3429|
|Yosuke INOUE||M1||Quark Nuclear Physics||noue||3422|
|Yuki KOSHOUJI||M1||Exotic Nuclear Physics||koshoji||3418|
|Mizuki SASAGAWA||M1||Quark Nuclear Physics||sasagawa||3433|
|Ryo TAJIMA||M1||Condensed Matter Nuclear Reaction||tajima||3426|
Administration Office (Radiation Safety Office)
|Administrative Assistant (Yumi SUGAWARA)||yumi||@||lns.tohoku.ac.jp||1140|
|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|
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 beamlineThe 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: firstname.lastname@example.org).
Photon beamline IIThe 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: email@example.com).
Positron/electron beamlines for testing detectorsThe 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|