1. Home
  2. Research
  3. Centers & Labs
  4. RIKEN Nishina Center for Accelerator-Based Science
  5. Nuclear Transmutation Data Research Group

RIKEN Nishina Center for Accelerator-Based Science Muon Data Team

Team Leader: Hiroyoshi Sakurai (D.Sc.)

Research Summary

Hiroyoshi  Sakurai

Dr. Yoshio Nishina observed muons in cosmic rays in 1937. The muon is an elementary particle belonging to the electron group, and is 207 times as heavy as the electron. The muon has positive or negative electric charge, and the lifetime is 2.2 μsec. The negative muon is caught by a nucleus (atomic number: Z) in materials to form a muonic atom, and is then captured by the nucleus. The negative muon is combined with a proton to convert to a neutron and a neutrino, and then creates excited states of the nucleus with the atomic number of Z-1, followed by emissions of neutrons and gamma rays. Therefore, the muon nuclear capture reaction produces the isotopes of (Z-1) nucleus. However, the reaction mechanism is not yet well clarified experimentally and theoretically. The research team aims at obtaining the experimental data to understand the mechanism of muon nuclear capture reaction as well as at establishing the reaction theory.

Main Research Fields

  • Mathematical & Physical Sciences

Related Research Fields

  • Interdisciplinary Science & Engineering


  • Muon transmutation
  • Muon nuclear capture reaction
  • Muon catalyzed fusion
  • Muon induced fission

Selected Publications

  • 1.T. Matsuzaki, K. Ishida, M. Iwasaki:
    "High-Pressure Solid Hydrogen Target for Muon Catalyzed Fusion"
    Journal of Radioanalytical and Nuclear Chemistry 305 (2015) 889-895.
  • 2.Y. Shimbara, T. Matsuzaki, K. Abe, Y. Fujita, J. Goto, T. Itoh, N. Kikukawa, M. Nagashima, Y. Nakamura, T. Ogura, T. Ohtsubo, S. Ohya, T. Sakai, D. Sera, S. Suzuki, K. Takeda, A. Yajima, T. Yoshikawa:
    "Observation of cosmic-ray muon-capture X-rays emitted from Al and Fe targets"
    J. Phys. Soc. Jpn. 84 (2015) 034301.
  • 3.N. Funamori1, K. M. Kojima, D. Wakabayashi1, T. Sato, T. Taniguchi, N. Nishiyama, T. Irifune, D. Tomono. T. Matsuzaki, M. Miyazaki, M. Hiraishi, A. Koda. R. Kadono:
    "Muonium in Stishovite: Implications for the Possible Existence of Neutral Atomic Hydrogen in the Earth’s Deep Mantle"
    Scientific Reports 5 (2015) 8437.
  • 4.K. Nishimura, K. Matsuda, R. Komaki, N. Nunomra, S. Wenner, R. Holmestad, T. Matsuzaki, I. Watanabe, F.L. Pratt:
    "Solute-Vacancy Clustering In Al-Mg-Si Alloys Studied By Muon Spin Relaxation Technique"
    Archives of Metallurgy of Materials 60 (2015) 925-929.
  • 5.Katsuhiko Nishimura, Kenji Matsuda, Takahiro Namiki, Norio Nunomra, Teiichiro Matsuzaki and Wayne D. Hutchison:
    "Time dependent magnetization of an Al-1.6%Mg2Si alloy"
    Materials Transactions 56 (2015) 1307-1309.
  • 6.S. Wenner, K. Nishimura, K. Matsuda, T. Matsuzaki, D. Tomono, F. L. Pratt, C. D. Marioara, R. Holmestad,:
    "Clustering and vacancy behavior in high- and low-solute Al-Mg-Si alloys"
    Metall. Mater. Trans. 45A (2014) 5777.
  • 7.K. Nishimura, K. Matsuda, R. Komaki, N. Nunomura, S. Wenner, R. Holmestad, T. Matsuzaki, I. Watanabe, F. L. Pratt, C. D. Marioara,:
    "μSR study of Al-0.67%Mg-0.77%Si alloys"
    J. Phys. Conference Series 551 (2014) 012031.
  • 8.S. Wenner, K. Nishimura, K. Matsuda, T. Matsuzaki, D. Tomono, F.L. Pratt, C. D. Marioara, R. Holmestad:
    "Muon kinetics in heat-treated Al (–Mg)(–Si) alloys"
    Acta Materialia, 61 (2013) 6082-6092.
  • 9.S. Wenner, R. Holmestad, K. Matsuda, K. Nishimura, T. Matsuzaki, D. Tomono, F. L. Pratt, C. D. Marioara:
    "Probing defects in Al-Mg-Si alloys using muon spin relaxation"
    Phys. Rev. B86 (2012) 104201.

Lab Members

Principal investigator

Hiroyoshi Sakurai
Team Leader

Core members

Teiichiro Matsuzaki
Contract Researcher

Contact Information

2-1 Hirosawa,
Wako, Saitama
351-0198, Japan
Email: sakurai [at] ribf.riken.jp