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Radioactive Isotope Physics Laboratory
Hiroyoshi SAKURAI
Chief Scientist
Hiroyoshi SAKURAI (D.Sci.)
mail

Research Areas

This laboratory explores exotic nuclear structures and dynamics in unstable nuclei that have never been investigated before, such as those with largely imbalanced proton and neutron numbers. Our aim is to develop new experimental techniques utilizing fast RI beams to discover new phenomena and properties in unstable nuclei. Another important subject is the equation-of-state of asymmetric nuclear matter, and its association with the origin of elements and with neutron stars. For instance, we are making attempts to the better understand underlyning mechanism for exotic stability-enhancements of very neutron-rich fluorine isotopes, the large deformation of the nucleus 34Mg with N=22 in spite of its vicinity to the N=20 magic neutron number and anomalous collectivity in 16C. We are further extending these studies to medium- and heavy-mass regions by developing facilities, detectors and unique methods at RIBF, thereby leading on the challenging task to find new exotic phenomena. We also perform numerical simulations of nucleosynthesis under the environment of core-collapse supernovae, and moreover quest for footprints of supernovae and solar activities in the past, embedded in Antarctic ice core, in collaboration with Cosmic radiation laboratory and National Institute of Polar Research.

Research Subject

  1. Study of structure and dynamics of unstable nuclei through development of new methods utilizing fast RI beamsI beams
  2. Stability of exotic nuclei and exploration into limit of nuclear existence
  3. Research on equation-of-state in asymmetric nuclear matter via heavy-ion induced reaction
  4. Promotion of nuclear astrophysics in an interdisciplinary organization

Related links

  1. RIKEN Nishina Center for Accelerator-Based Science Website_Laboratories PageNew Window

Press release

February 01,2011
New evidence shows elements synthesized in super-nova explosions much faster than thought
June 06,2007
Nishina Center for Accelerator Based Science succeeded in synthesis of a new isotope with RIBF, revealing the high potentiality of RI producibility

RIKEN RESEARCH

September 18,2009
Too many neutrons break the rules
Unusual behavior in an exotic isotope of neon challenges the traditional foundations of nuclear physics New Window
September 05,2008
Miniscule nuclear molecules
A theoretical study of a beryllium isotope shows the formation of several molecular states between subunits of the nucleus New Window

List of Selected Publications

  1. Nishimura S., Li Z, Watanabe H., Yoshinaga K, et al.:
    "Beta-Decay Half-Lives of Very Neutron-Rich Kr to Tc Isotopes on the Boundary of the r-Process Path: An Indication of Fast r-Matter Flow"
    Phys. Rev. Lett. 106, 052502 (2011)
  2. Doornenbal P, Scheit H, Aoi N, Takeuchi S, et al.:
    "Spectroscopy of Ne-32 and the "Island of Inversion""
    Phys. Rev. Lett. 103, 152503 (2009)
  3. Suzuki D., Iwasaki H., Otsu H., et al.,:
    "Breakdown of the Z=8 Shell Closure in Unbound O-12 and its Mirror Symmetry"
    Phys. Rev. Lett. 103, 152503 (2009)
  4. Suzuki D., Iwasaki H., Ong HJ., Imai N., Sakurai H., Nakao T., Aoi N., Baba H., et al.:
    "Lifetime measurements of excited states in C-17:Possible interplay between collectivity and halo effects"
    Physics Letters B 666, 222-227 (2008)
  5. Ong, H. J., Imai, N., Suzuki D., Iwasaki H., Sakurai H., Onishi T.K., Suzuki M.K., Ota S., Takeuchi S., Nakao T., et al.:
    "Lifetime measurements of first excited states in C-16, C-18"
    Physical Review C 78, 014308 (2008)
  6. Madokoro, H., Shimizu, T., and Motizuki, Y.:
    "Importance of prolate neutrino radiation in core-collapse supernovae: the reason for the prolate geometry of SN1987A?"
    Pub. Astron. Soc. Japan, 56, 663-669 (2004)
  7. T.K. Onishi, A. Gelberg, H. Sakurai et al.:
    "Gamow-Teller decay of the T=1 nucleus 46Cr"
    Phys. Rev. C 72, 024308 (2005)
  8. Notani, M., Sakurai, H., Aoi, N., Yanagisawa, Y., Saito, A., Imai, N., Gomi, T., Miura, M., Michimasa, S., Iwasaki, H., Fukuda, N., Ishihara, M., Kubo, T., Kubono, S., Kumagai, H., Lukyanov, S.M., Motobayashi, T., Onishi, T.K., Penionzhkevich, Yu.E., Shim,:
    "New neutron-rich isotopes, 34Ne, 37Na and 43Si, produced by fragmentation of a 64A MeV 48Ca beam"
    Physics Letters B 542, 49-54 (2002).
  9. Yoneda, K., Sakurai, H., Gomi, T., Motobayashi, T., Aoi, N., Fukuda, N., Futakami, U., Gacsi, Z., Higurashi, Y., Imai, N., Iwasa, N., Iwasaki, H., Kubo, T., Kunibu, M., Kurokawa, M., Liu, Z., Minemura, T., Saito, A., Serata, M., Shimoura, S., Takeuchi, S.:
    "Deformation of 34Mg studied via in-beam -ray spectroscopy using RI beam fragmentation"
    Physics Letters B 499, 233-237 (2001).
  10. Sakurai, H., Lukyanov, S.M., Notani, M., Aoi, N., Beaumel, D., Fukuda, N., Hirai, M., Ideguchi, E., Imai, N., Ishihara, M., Iwasaki, H., Kubo, T., Kusaka, K., Kumagai, H., Nakamura, T., Ogawa, H., Penionzhkevich, Yu.E., Teranishi, T., Watanabe, Y.X., Yone,:
    "Evidence for particle stability of 31F and particle instability of 25N and 28O"
    Physics Letters B 448, 180-184 (1999).

Members

Principal Investigator

Hiroyoshi SAKURAI
Chief Scientist

Staff Scientist

Takashi ICHIHARA
Vice Chief Scientist
Yukari MATSUO
Senior Research Scientist
Takashi KISHIDA
Senior Research Scientist
Shunji NISHIMURA
Senior Research Scientist
Yoichi NAKAI
Senior Research Scientist
Hideaki OTSU
Senior Research Scientist
Tadaaki ISOBE
Research Scientist
Hiu Ching LEE
Research Scientist

Postdoctoral Fellow

Juzo ZENIHIRO
Special Postdoctoral Researcher
Daiki NISHIMURA
Special Postdoctoral Researcher
Zhihuan LI
Foreign Postdoctoral Researcher
Pieter Christiaan DOORNENBAL
Foreign Postdoctoral Researcher
David STEPPENBECK
Foreign Postdoctoral Researcher
Taro NAKAO
Postdoctoral Researcher
Mizuki NISHIMURA
Research Associate
Satoshi TAKEUCHI
Research Associate
Hiroshi WATANABE
Research Associate
Giuseppe LORUSSO
Visiting Researcher
Paer-Anders SOEDERSTROEM
Visiting Researcher

Student Trainee

Masafumi MATSUSHITA
Junior Research Associate
He WANG
International Program Associate
Ruijiu CHEN
International Program Associate
Xiaofei YANG
International Program Associate
Hongna LIU
International Program Associate
Kenta YOSHINAGA
Junior Research Associate
Masami SAKO
Junior Research Associate
Shintaro GO
Junior Research Associate