The unbound isotopes 9,10He

H. T. Johansson, Yu Aksyutina, T. Aumann, K. Boretzky, M. J G Borge, A. Chatillon, L. V. Chulkov, D. Cortina-Gil, U. Datta Pramanik, H. Emling, C. Forssén, H. O U Fynbo, H. Geissel, G. Ickert, B. Jonson*, R. Kulessa, C. Langer, M. Lantz, T. LeBleis, K. MahataM. Meister, G. Münzenberg, T. Nilsson, G. Nyman, R. Palit, S. Paschalis, W. Prokopowicz, R. Reifarth, A. Richter, K. Riisager, G. Schrieder, H. Simon, K. Sümmerer, O. Tengblad, H. Weick, M. V. Zhukov

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


The unbound nuclei 9He and 10He have been produced in proton-knockout reactions from a 280 MeV/u 11Li beam impinging on a liquid hydrogen target at the ALADIN-LAND setup at GSI. Information on their nuclear structure has been obtained from the relative-energy spectra, He8+n and He8+2n, employing reaction models incorporating the structure of 11Li.The He8+n relative-energy spectrum is dominated by a strong peak-like structure at low energy, which may be interpreted within the effective-range approximation as the result of an s-wave interaction with a neutron scattering length of -3.17(66) fm. This spectrum also shows evidence for resonance states at 1.33(8) MeV and at 2.4 MeV above the He8+n threshold. It is argued that the s-state might not be the 9He ground state.For He8+n+n, the analysis of the relative-energy spectrum gives two alternative possibilities for an interpretation: either a narrow resonance at 1.42(10) MeV (Γ=1.11(76) MeV) superimposed on a correlated background, or two overlapping resonances, a ground state at 1.54(11) MeV (Γ=1.91(41) MeV) together with an excited state at 3.99(26) MeV (Γ=1.64(89) MeV). The two possible interpretations are discussed.

Original languageEnglish
Pages (from-to)15-32
Number of pages18
JournalNuclear Physics A
Issue number1-4
Publication statusPublished - Oct 2010


  • Deduced resonance state parameters
  • Measured
  • Nuclear reactions

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