Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

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Structure of high-spin states in 91Sr and 92Sr

Stefanova, E.; Danchev, M.; Schwengner, R.; Balabanski, D.; Carpenter, M.; Djongolov, M.; Fischer, S.; Hartley, D.; Janssens, R.; Mueller, W.; Nisius, D.; Reviol, W.; Riedinger, L.; Zeidan, O.


The nuclei $^{91}$Sr and $^{92}$Sr were produced at high spin as fission fragments following the fusion reaction $^{36}$S + $^{159}$Tb at 165 MeV. Gamma rays were detected with the Gammasphere array. The level schemes of
$^{91}$Sr and $^{92}$Sr were extended up to $E \approx$ 6 MeV and $E \approx$ 8 MeV, respectively. Level structures in $^{91}$Sr and $^{92}$Sr were interpreted in terms of the shell model. The calculations were performed in the configuration space $(0f_{5/2}, 1p_{3/2}, 1p_{1/2}, 0g_{9/2})$ for the
protons and $(1p_{1/2}, 0g_{9/2}, 1d_{5/2})$ for the neutrons. Negative-parity states in the yrast sequences are described in these calculations by coupling $3^-$ proton excitations to the unpaired $1d_{5/2}$ neutrons. A possible reduction of the gap between the proton $1p_{3/2}$ and $1p_{1/2}$ orbitals in
$^{92}$Sr is discussed.

Keywords: Nuclear structure; In-beam spectroscopy; Gammasphere detector array; Shell-model calculations

  • Physical Review C, Vol. 65, 034323