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Instrumentation Development Group

Leader's Photo
Group Director
Tetsuya ONISHID.Sci.
  • 1984年北海道大学理学部卒業
  • 1990年広島大学大学院理学研究科物理学専攻修了
  • 1991年理化学研究所基礎科学特別研究員
  • 1992年理化学研究所サイクロトロン研究室研究員
  • 2008年仁科加速器研究センター実験装置開発室長

Research Areas

This group develops core experimental instrumentations for the RI Beam factory, which consists of unique instrumentations. The SCRIT (Self-Confining RI Ion Target) and the R3 (Rare-RI Ring) are provide storage ring experiments for specific purpose and their operation have been already started. All are designed to maximize the research potential of the world's most intense RI beams, Beam-manipulation techniques, such as a beam accumulation and a beam cooling, will be able to provide opportunities of new experimental challenge and the foundation for future development of RIBF. For the future, we are also developing an ion storage ring for nuclear reaction experiments with unstable nuclei.


We aim at the investigation of internal nuclear structure of short-lived radioactive nuclei (RI) by means of electron scattering. Electron scattering for RI's has never been performed duo to inability to make target of these nuclei. An electron-RI collider system, which requires a huge accelerator complex, has so far been unique solution to overcome the difficulty. We have developed a novel internal target system named SCRIT (Self-Confining RI Ion Target) in an electron storage ring to make the experiment easier with much compact experimental system.
The commissioning experiment using stable Xe ions was conducted at 2016. After the development of RI production and SCRIT techniques, the electron scattering experiment using online-produced unstable nuclei, which is 137Cs ions, was successfully performed at 2022. Further development for the experiment using short-lived and rarely-produced unstable nuclei is in progress.

Laboratory image photo

Rare-RI Ring

We are developing the isochronous storage ring to measure the mass for rare radioactive isotopes (Rare RI ring). It is assumed that uranium is synthesized by neutron capture process after the supernovae explosion (r-process). To prove r-process, mass measurements for the rare RI is indispensable. It is possible to inject the rare RI one by one to the ring (individual injection) since cyclotrons in RIBF provide continuous beams. The isochronous storage ring and the individual injection are very unique system.


Research Subject

  1. Developments of the SCRIT technology and electron scattering for unstable nuclei
  2. Developments of isochronous storage ring to measure mass of rare RI
  3. Developments of ion storage ring for nuclear reaction experiment

List of Selected Publications


  1. K. Tsukada, Y. Abe, A. Enokizono, T. Goke, M. Hara, Y. Honda, T. Hori, S. Ichikawa, Y. Ito, K. Kurita, C. Legris, Y. Maehara, T. Ohnishi, R. Ogawara, T. Suda, T. Tamae, M. Wakasugi, M. Watanabe, and H. Wauke, “First observation of electron scattering from online-produced radioactive target”, Phys. Rev. Letters 131, 092502 (2023).
  2. R. Ogawara, Y. Abe, T. Ohnishi, A. Enokizono, M. Hara, T. Hori, S. Ichikawa, K. Kurita, Y. Maehara, T. Suda, K. Tsukada, M. Wakasugi, M. Watanabe, H. Wauke, “Ion-trapping properties of SCRIT: Time evolutions of 138Ba charge state distributions”, Nuclear Instrumentation and Methods in Physics Research Section B 541, 90 (2023).
  3. T. Ohnishi, D. Abe, Y. Abe, R. Danjyo, A. Enokizono, T. Goke, M. Hara, Y. Honda,T. Hori, S. Ichikawa, S. Iimura, Y. Ishikura, K. Ishizaki, Y. Ito, K. Kurita, C. Legris,Y. Maehara, Y. Nagano, R. Obara, R. Ogawara, T. Suda, T. Tamae, K. Tsukada, M. Wakasugi, M. Watanabe, H. Wauke, T. Yamano, S. Yoshid, “The SCRIT electron scattering facility at RIKEN RI Beam Factory.”, Nuclear Instrumentation and Methods in Physics Research Section B 541, 380 (2023).
  4. M. Wakasugi, M. Togasaki, T. Ohnishi, K. Kurita, R. Toba, M. Watanabe and K. Yamada, “FRAC: Fringing-RF-field-activated dc-to-pulse converter for low-energy ion beams”, Review of Scientific Instruments 89, 095107 (2018).
  5. K. Tsukada, A. Enokizono, T. Ohnishi, K. Adachi, T. Fujita, M. Hara, M. Hori, T. Hori, S. Ichikawa, K. Kurita, K. Matsuda, T. Suda, T. Tamae, M. Togasaki, M. Wakasugi, M. Watanabe, and K. Yamada, “First Elastic Electron Scattering from 132Xe at the SCRIT Facility”, Physical Review Letters 118, 262501 (2017).
  6. M. Wakasugi, T. Ohnishi, S. Wang, Y. Miyashita, T. Adachi, T. Amagai, A. Enokizono, A. Enomoto, Y. Haraguchi, M. Hara, T. Hori, S. Ichikawa, T. Kikuchi, R. Kitazawa, K. Koizumi, K. Kurita, T. Miyamoto, R. Ogawara, Y. Shimakura, H. Takehara, T. Tamae, S. Tamaki, M. Togasaki, T. Yamaguchi, K. Yanagi, and T. Suda, “Construction of the SCRIT electron scattering facility at the RIKEN RI Beam Factory” Nuclear Instruments and Methods in Physics Research Section B 317, 668 (2013).

Rare-RI Ring

  1. S. Naimi, Y. Yamaguchi, T. Yamaguchi, A. Ozawa, “Recent achievements at the Rare-RI Ring, a unique mass spectrometer at the RIBF/RIKEN”, European Physical Journal A, 59:90 (2023)
  2. H. F. Li, S. Naimi, T. M. Sprouse, M. R. Mumpower, Y. Abe, Y. Yamaguchi, D. Nagae, F. Suzaki, M. Wakasugi, H. Arakawa, W. B. Dou, D. Hamakawa, S. Hosoi, Y. Inada, D. Kajiki, T. Kobayashi, M. Sakaue, Y. Yokoda, T. Yamaguchi, R. Kagesawa, D. Kamioka, T. Moriguchi, M. Mukai, A. Ozawa, S. Ota, N. Kitamura, S. Masuoka, S. Michimasa, H. Baba, N. Fukuda, Y. Shimizu, H. Suzuki, H. Takeda, D. S. Ahn, M. Wang, C. Y. Fu, Q. Wang, S. Suzuki, Z. Ge, Yu. A. Litvinov, G. Lorusso, P. M. Walker, Zs. Podolyak and T. Uesaka, “First Application of Mass Measurements with the Rare-RI Ring Reveals the Solar r-process Abundance Trend at A = 122 and A = 123”, Physical Review Letters 128, 152701 (2022).
  3. D. Nagae, Y. Abe, S. Okada, S. Omika, K. Wakayama, S. Hosoi, S. Suzuki, T. Moriguchi, M. Amano, D. Kamioka, Z. Ge, S. Naimi, F. Suzaki, N. Tadano, R. Igosawa, K. Inomata, H. Arakawa, K. Nishimuro, T. Fujii, T. Mitsui, Y. Yanagisawa, H. Baba, S. Michimasa, S. Ota, G. Lorusso, Yu. A. Litvinov, A. Ozawa, T. Uesaka, T. Yamaguchi, Y. Ymaguchi, and M. Wakasugi, “Development and operation of an electrostatic time-of-flight detector for the Rare RI storage Ring”, Nucl. Instrum. Methods Phys. Res. A 986, 164713-1‒7 (2020).
  4. S. Suzuki, A. Ozawa, D. Kamioka, Y. Abe, M. Amano, H. Arakawa, Z. Ge, K. Hiraishi, Y. Ichikawa, K. Inomata, A. Kitagawa, T. Kobayashi, H. F. Li, T. Matsumoto, T. Moriguchi, M. Mukai, D. Nagae, S. Naimi, S. Omika, S. Sato, Y. Tajiri, K. Wakayama, and T. Yamaguchi, “Efficiency and timing performance of time-of-flight detector utilizing thin foils and crossed static electric and magnetic fields for mass measurements with Rare-RI Ring facility”, Nucl. Instrum. Methods Phys. Res. A 965, 163807-1‒14 (2020).
  5. Y. Yamaguchi, M. Wakasugi, T. Uesaka, A. Ozawa, Y. Abe, T. Fujinawa, M. Kase, M. Komiyama, T. Kubo, K. Kumagai, T. Maie, D. Nagae, J. Ohnishi, F. Suzaki, A. Tokuchi, Y. Watanabe, K. Yoshida, K. Yamada, T. Yamaguchi, H. Yamasawa, Y. Yanagisawa, J. Zenihiro, Y. Yano, “Construction of rare-RI ring at RIKEN RI Beam Factory”, Nuclear Instrumentation and Methods in Physics Research B 317, 629 (2013).
  6. A. Ozawa, T. Uesaka and M. Wakasugi, the Rare-RI Ring Collaboration, “The rare-RI ring”, Progress of Theoretical and Experimental Physics 03C009 (2012).