Collective Band Structures in Neutron-Rich $^{108}$Mo Nucleus

ORAL

Abstract

High spin states in the neutron-rich $^{108}$Mo nucleus were studied by measuring prompt $\gamma $-rays following the spontaneous fission of $^{252}$Cf with the Gammasphere detector array. Our high statistics data, 5.7 x 10$^{11}$ triple coincidences, enabled us to see new bands. The ground-state band is confirmed, and the one-phonon $\gamma $-vibrational band is extended up to spin 12. Three new unexpected states are found to feed into the ground and one-phonon $\gamma $-band 6$^{+}$ and 8$^{+}$ states. A new collective band with a band head at 1422.4 keV is observed with energy spacing similar to the one-phonon $\gamma $-band and feeding only into this band. These data suggest its assignment as a two-phonon $\gamma $-vibrational band. Such bands are seen in $^{104,106}$Mo. Another new band is proposed as a two-quasi-proton excitation band. Systematic characteristics of the collective bands will be discussed.

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Authors

  • H.B. Ding

    • Tsinghua University

  • S.J. Zhu

    • Tsinghua University

  • J.H. Hamilton

    • Vanderbilt University

  • A.V. Ramayya

    • Vanderbilt University

  • J.K. Hwang

    • Vanderbilt University

  • Y.X. Luo

    • Vanderbilt University, Lawrence Berkeley National Lab

  • J.O. Rasmussen

    • Lawrence Berkeley National Lab

  • I.Y. Lee

    • Lawrence Berkeley National Lab

  • X.L. Che

    • Tsinghua University

  • J.G. Wang

    • Tsinghua University

  • Q. Xu

    • Tsinghua University