New short-lived isotope 223Np and the absence of the Z = 92 subshell closure near N = 126

• DOI: 10.1016/j.physletb.2017.03.074
• Publication Date: 2017-05-20T00:16:31Z
• Authors: M.D. Sun; Z. Liu; T.H. Huang; W.Q. Zhang; J.G. Wang; X.Y. Liu; B. Ding; Z.G. Gan; L. Ma; H.B. Yang; Z.Y. Zhang; L. Yu; J. Jiang; K.L. Wang; Y.S. Wang; M.L. Liu; Z.H. Li; J. Li; X. Wang; H.Y. Lu; C.J. Lin; L.J. Sun; N.R. Ma; C.X. Yuan; W. Zuo; H.S. Xu; X.H. Zhou; G.Q. Xiao; C. Qi; F.S. Zhang
• Keywords: Recoil; Decay chain; Separator (oil production); Parity (physics)

The N=130 short-lived isotope 223Np was produced as evaporation residue (ER) in the fusion reaction 40Ar + 187Re at gas-filled recoil separator Spectrometer for Heavy Atom and Nuclear Structure (SHANS). It identified through temporal spatial correlations with α decays of 215Ac and/or 211Fr, third fourth members α-decay chain starting from 223Np. pileup signals ER(223Np)–α(223Np)–α(219Pa) were resolved by using digital pulse processing technique. An decay half-life T1/2=2.15(52100) μs energy Eα=9477(44)keV attributed to Spin parity 9/2− tentatively proposed ground state combining reduced width large-scale shell-model calculations. This assignment together proton separation disprove existence a Z=92 subshell closure.