90 research outputs found
Exact diagonalization of the Bohr Hamiltonian for rotational nuclei: Dynamical gamma softness and triaxiality
Detailed quantitative predictions are obtained for phonon and multiphonon
excitations in well-deformed rotor nuclei within the geometric framework, by
exact numerical diagonalization of the Bohr Hamiltonian in an SO(5) basis.
Dynamical gamma deformation is found to significantly influence the predictions
through its coupling to the rotational motion. Basic signatures for the onset
of rigid triaxial deformation are also obtained.Comment: 17 pages, 10 figures; to be published Phys. Rev.
Investigation of octupole vibrational states in 150Nd via inelastic proton scattering (p,p'g)
Octupole vibrational states were studied in the nucleus
via inelastic proton scattering with \unit[10.9]{MeV} protons which are an
excellent probe to excite natural parity states. For the first time in
, both the scattered protons and the rays were
detected in coincidence giving the possibility to measure branching ratios in
detail. Using the coincidence technique, the ratios of the decaying
transitions for 10 octupole vibrational states and other negative-parity states
to the yrast band were determined and compared to the Alaga rule. The positive
and negative-parity states revealed by this experiment are compared with
Interacting Boson Approximation (IBA) calculations performed in the (spdf)
boson space. The calculations are found to be in good agreement with the
experimental data, both for positive and negative-parity states
Parity assignments in 172,174Yb using polarized photons and the K quantum number in rare earth nuclei
The 100 % polarized photon beam at the High Intensity gamma-ray Source (HIgS)
at Duke University has been used to determine the parity of six dipole
excitations between 2.9 and 3.6 MeV in the deformed nuclei 172,174 Yb in photon
scattering (g,g') experiments. The measured parities are compared with previous
assignments based on the K quantum number that had been assigned in Nuclear
Resonance Fluorescence (NRF) experiments by using the Alaga rules. A systematic
survey of the relation between gamma-decay branching ratios and parity quantum
numbers is given for the rare earth nuclei.Comment: 5 pages, 6 figures, to be published in Phys. Rev.
Nuclear structure of Ac-231
The low-energy structure of 231Ac has been investigated by means of gamma ray
spectroscopy following the beta-decay of 231Ra. Multipolarities of 28
transitions have been established by measuring conversion electrons with a
mini-orange electron spectrometer. The decay scheme of 231Ra --> 231Ac has been
constructed for the first time. The Advanced Time Delayed beta-gamma-gamma(t)
method has been used to measure the half-lives of five levels. The moderately
fast B(E1) transition rates derived suggest that the octupole effects, albeit
weak, are still present in this exotic nucleus
Identical transitions in the strongly deformed Sr-99 and Sr-100
The decay of the very neutron-rich nucleus Rb-100 has been studied by
gamma-spectroscopy of on-line mass-separated samples. Schemes for beta-decay to
Sr-100 and beta-n-decay to Sr-99 are presented. New sets of transitions in
Sr-99 and Sr-100 with identical energies are observed. All identical bands so
far observed in neutron-rich Sr isotopes obey a simple energy rule valid for
even-even, odd-even and odd-odd bands.Comment: 31 pages, 7 figures, Phys. Rev. C, in prin
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