EuNPC2015

The half-lives of yrast states in 86,87Rb isotopes, produced in 82Se(7Li, xn) reactions, were measured using the ROSPHERE gamma spectrometer. The experimental evidences prior to this measurements lead to the conclusion that 1p-2h proton configurations which involve the g9/2, f5/2, p3/2 orbitals are energetically favored to appear in this mass region with N~50 for states at excitation energies lower than ~4 MeV. At higher excitation energies, the neutron core breaks and neutron p-h excitations have to be considered. The proton hole f5/2p3/2 orbitals are responsible for delayed gamma decay of these states in neighboring Kr isotopes, having lifetimes in the nanosecond region. It is expected that this configuration to determine the existence of an isomeric state in 87Rb. Also, the experimental evidence concerning the spins and parities for these states located at a medium excitation energy in 87Rb is rather scarce. Of interest in the present work was to investigate the structure of excited states in the Rb isotopes, using the in-beam fast timing technique. From this measurements, the gamma decay multipole could be deduced.