0000000000262582
AUTHOR
J.c. Merdinger
Evidence for a two-phonon octupole vibrational state in208Pb
Collective properties of206,208Pb have been investigated with gamma-ray spectroscopy using nuclear and electromagnetic excitation by208Pb projectiles. From the measurement of particle-particle-γ and particle-particle-γ γ coincidences a new energy level in208Pb at 5.683 MeV was observed and the data suggest an interpretation as a 2-phonon octupole vibrational state with spin 4+ or 6+. For this state one finds the same dynamical deformation parameterβ3 as for the first-excited collective 3− state. The results are compared to predictions of models which consider, in particular, the aspects of the quadrupole interaction and the interaction of the 2-particle pairing vibration with the 2-phonon o…
Influence of fusion barrier distributions on spin populations
Abstract Heavy-ion fusion barrier distributions are now routinely obtained directly from experimental data. By measuring the total γ -ray multiplicity for the 58 Ni + 60 Ni system, which has a striking yet well understood barrier distribution, we show that some evidence of the barrier structures is present in the derived spin populations. In particular, very high spins can be populated at energies rather close to (and even below) the ‘nominal’ Coulomb barrier.
Gamma-spectroscopy of the 199At nucleus with the recoil filter detector
The neutron deficient 199At nucleus has been studied in the 175Lu+28Si reaction at Eb= 141 MeV. In order to select events of interest in the presence of the very strong background caused by fission, γ-rays have been detected in coincidence with recoiling evaporation residues. The excited states of 199At observed for the first time may indicate that this nucleus is deformed.
The g-factor of the J?=12+ isomeric state in188Hg
Using the reaction175Lu(19F, 6n) theg-factor of the188Hg isomeric state (Jπ=12+,T1/2=135 ns) has been measured with the TDPAD method. The experimental value g=−0.168(10) supports the interpretation of an almost pure (vi13/2)−2 configuration for this isomer.