gamma-ray spectroscopy of neutron-rich S-40

Yrast states up to (6(+)) in the neutron-rich S-40 nucleus have been studied using binary grazing reactions produced by the interaction of a 215 MeV beam of S-36 ions with a thin Pb-208 target. The novel experimental setup that combines the large acceptance magnetic spectrometer, PRISMA, and the high-efficiency gamma-ray detection array, CLARA, was used. A new gamma-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 (h) over bar omega sd-pf shell-model calculations indicates that one- and two-proton excitations from the 2s(1/2) to the 1d(3/2) orbitals play an important role in reproducing the S-40 yrast level structure and the published B(E2; 0(g.s).(+) 2(1)(+)) 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 (h) over bar omega sd-pf shell-model calculations.