Physics Letters B (Jan 2020)

A new isomeric state in 218Pa

  • M.M. Zhang,
  • H.B. Yang,
  • Z.G. Gan,
  • Z.Y. Zhang,
  • M.H. Huang,
  • L. Ma,
  • C.L. Yang,
  • C.X. Yuan,
  • Y.S. Wang,
  • Y.L. Tian,
  • H.B. Zhou,
  • S. Huang,
  • X.T. He,
  • S.Y. Wang,
  • W.Z. Xu,
  • H.W. Li,
  • X.X. Xu,
  • J.G. Wang,
  • H.R. Yang,
  • L.M. Duan,
  • W.Q. Yang,
  • S.G. Zhou,
  • Z.Z. Ren,
  • X.H. Zhou,
  • H.S. Xu,
  • A.A. Voinov,
  • Yu.S. Tsyganov,
  • A.N. Polyakov,
  • M.V. Shumeiko

Journal volume & issue
Vol. 800

Abstract

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The decay of 218Pa was investigated by means of α and γ spectroscopy. The nucleus was produced in the fusion reaction 40Ar+182W and separated in flight by the gas-filled recoil separator SHANS (Spectrometer for Heavy Atoms and Nuclear Structure). The known α decays of 218Pa were measured with improved precision and newly assigned to be originating from the ground state, which clarified the ambiguities in their previous assignments. In addition, a new isomeric state in 218Pa decaying with α-particle energies of 9691(15) keV, 9595(21) keV and a half-life of 135−32+62 μs was identified. The spins and parities of the involved states were tentatively assigned on the basis of the systematic α-decay properties of the odd-proton N=127 isotones and shell model calculations. Keywords: Odd-proton N=127 isotones, Isomeric state, α-particle energy, Half-life, Shell model calculation, Spin and parity