Centers & Labs

RIKEN Nishina Center for Accelerator-Based Science

SLOWRI Team

Team Leader: Michiharu Wada (D.Sci.)
Michiharu  Wada(D.Sci.)

SLOWRI is a universal low-energy RI-beam facility at RIBF that provides a wide variety of short-lived nuclei as high-purity and low-emittance ion beams or stored ions in a trap, including a parasitic operation mode. The SLOWRI team develops and manages the facility and performs high-precision spectroscopy experiments. The construction of the SLOWRI facility began in FY2013 and commissioning work has been ongoing. Two major online prototype setups have been successfully tested. The first was a large room-temperature gas cell with RF-carpet structure. With this setup, the hyperfine structure constants of all odd Be isotopes were precisely measured by laser-microwave double resonance spectroscopy of trapped Be ions, followed by the first online mass measurement with a multi-reflection time-of-flight mass spectrograph (MRTOF) performed on 8Li+ ions. The second prototype is a medium-sized cryogenic RF-carpet gas cell for the SHE-Mass project that aims to measure masses of trans-uranium elements at the GARIS-II facility. This prototype showed that a traveling-wave RF-carpet works fine and the cryogenic gas cell dominantly provides doubly charged ions even for Fr isotopes.

Main Research Field

Mathematical and physical sciences

Keywords

  • Nuclear Properties
  • Laser Spectroscopy
  • Ion Trap
  • Mass Spectrometry
  • Radio frequency ion beam manipulation

Selected Publications

  1. Schury, P., Wada, M., Ito, Y., Kaji, D., Arai, F., MacC ormick, M., Murray, I., Haba, H., Jeong, S., Kimura, S., Koura, H., Miyatake, H., Morimoto, K., Morita, K., Ozawa, A., Rosenbusch, M., Reponen, M., Söderström, P.-A., Takamine, A., Tanaka, T., Wollnik, H.:
    "First online multireflection time-of-flight mass measurements of isomer chains produced by fusion-evaporation reactions: Toward identification of superheavy elements via mass spectroscopy"
    Physical Review C 95, 011305(R) (2017)
  2. Takamine, A., Wada, M., Okada, K., Sonoda, T., Schury, P., Nakamura, T., Kanai, Y., Kubo, T., Katayama, I., Ohtani, S., Wollnik, H., Schuessler, H.A.:
    "Hyperfine Structure Constant of the Neutron Halo Nucleus 11Be+"
    Phys. Rev. Lett., 112, 162502 (2014)
  3. Ito, Y., Schury, P., Wada, M., Naimi, S., Sonoda, T., Mita, H., Arai, F., Takamine, A., Okada, K., Ozawa, A., Wollnik, H.:
    "Single-reference high-precision mass measurement with a multireflection time-of-flight mass spectrograph"
    Phys. Rev. C 88, 011306® (2013)
  4. Okada, K., Wada, M., Nakamura, T., Takamine, A., Lioubimov, V., Schury, P., Ishida, Y., Sonoda, T., Ogawa, M., Yamazaki, Y., Kambara, T., Kanai, Y., Kojima, T.M., Yoshida A., Kubo, T., K., Katayama, I., Ohtani, S., Wollnik, H., Schuessler, H.A.:
    "Precision Measurements of the hyperfine Structure of Laser-Cooled Radioactive 7Be+ ions Produced by Projectile Fragmentation"
    Phys. Rev. Lett. 101, 212502 (2008)
  5. Takamine, A., Wada, M., Okada, K., Nakamura, T., Schury, P., Sonoda, T., Lioubimov, V., Iimura, H., Yamazaki, Y., Kanai, Y., Kojima, T.M., Yoshida, A., Kubo, T., Katayama, I., Ohtani, S., Wollnik, H., Schuessler, H.A.:
    "Isotope shift measurements of 11,9,7Be+"
    Eur. Phys. J. A. 10883-5 (2009)
  6. Schury, P., Wada, M., Ito, Y., Arai, F., Naimi, S., Sonoda, T., Wollnik, H., Shchepunov, V.A., Smorra, C., Yuan, C.:
    "A high-resolution multi-reflection time-of-flight mass spectrograph for precision mass measuremets at RIKEN/SLOWRI"
    Nucl. Inst. And Meth. Phys. Res. B335, 39 (2014)
  7. Sonoda, T., Tsubota, T., Wada, M., Katayama, I., Kojima, T.M., Reponen, M.:
    "A gas circulation and purification system for gas-cell based low-energy RI-beam production"
    Rev. Sci. Inst., 87, 065104 (2016).
  8. Wada, M.:
    "Genealogy of gas cells for low-energy RI-beam production"
    Nucl. Inst. and Meth. Phys. Res. B 317, 450 (2013).
  9. Takamine, A., Wada, M., Ishida, Y., Nakamura, T., Okada, K., Yamazaki, Y., Kambara, T., Kanai, Y., Kojima, T.M., Nakai, Y., Oshima, N., Yoshida, A., Kubo, T., Ohtani, S., Noda, K., Katayama, I., Hostain, P., Varentsov, V., Wollnik, H.:
    "Space-charge effect in the catcher gas cell of a rf ion guide"
    Rev. Sci. Instrum. 76, 103503 (2005)
  10. Wada, M., Ishida, Y., Nakamura, T., Yamazaki, Y., Kambara, T., Ohyama, H., Kanai, Y., Kojima, T.M., Nakai, Y., Yoshida, A., Kubo, T., Matsuo, Y., Fukuyama, Y., Okada, K., Sonoda, T., Ohtani, S., Noda, K., Kawakami, H., Katayama, I.:
    "Slow RI-beams from projectile fragment separators"
    Nucl. Instrum. and Meth. B204, 570-581 (2003)

Lab Members

Principal Investigator

Michiharu Wada
Team Leader

Core Members

Takao Kojima
Senior Research Scientist
Tetsu Sonoda
Nishina Center Research Scientist
Takeshi Maie
Nishina Center Technical Scientist
Marco Rosenbusch
Special Postdoctoral Researcher

Contact information

RIBF 415
2-1 Hirosawa,
Wako, Saitama
351-0198, Japan

Email: mw [at] riken.jp

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