γ-ray spectroscopy of neutron-rich S40

Yrast states up to (6+) in the neutron-rich S40 nucleus have been studied using binary grazing reactions produced by the interaction of a 215 MeV beam of S36 ions with a thin Pb208 target. The novel experimental setup that combines the large acceptance magnetic spectrometer, PRISMA, and the high-efficiency γ-ray detection array, CLARA, was used. A new γ-ray transition at an energy of 1572 keV was observed and tentatively assigned to the (6+)→(4+) transition. A comparison of experimental observations and the results of large-scale 0 ω sd-pf shell-model calculations indicates that one- and two-proton excitations from the 2s1/2 to the 1d3/2 orbitals play an important role in reproducing the S40 yrast level structure and the published B(E2;0g.s.+→21+) value. The structure of the yrast states of the even-A isotopes of sulfur is interpreted in terms of the configurations of valence protons and neutrons within the context of large-scale 0 ω sd-pf shell-model calculations. © 2010 The American Physical Society.Supported in part by the EPSRC (UK) and by the European Union under Contract No. RII3-CT-2004-506065. Support from STFC. Support from ORSAS and from the University of the West of Scotland. Support from the Spanish Ministerio de Ciencia e Innovación under Contract Nos. FPA2007-66069 and FPA2009-13377-C02-02. Support from OTKA Project No. K68801.Peer Reviewe