600 research outputs found
The Single-Particle Structure of Neutron-Rich Nuclei of Astrophysical Interest at the Ornl Hribf
The rapid nuetron-capture process (r process) produces roughly half of the
elements heavier than iron. The path and abundances produced are uncertain,
however, because of the lack of nuclear strucure information on important
neutron-rich nuclei. We are studying nuclei on or near the r-process path via
single-nucleon transfer reactions on neutron-rich radioactive beams at ORNL's
Holifield Radioactive Ion Beam Facility (HRIBF). Owing to the difficulties in
studying these reactions in inverse kinematics, a variety of experimental
approaches are being developed. We present the experimental methods and initial
results.Comment: Proceedings of the Third International Conference on Fission and
Properties of Neutron-Rich Nucle
Relativistic Hartree-Bogoliubov description of the deformed ground-state proton emitters
Ground-state properties of deformed proton-rich odd-Z nuclei in the region
are described in the framework of Relativistic Hartree
Bogoliubov (RHB) theory. One-proton separation energies and ground-state
quadrupole deformations that result from fully self-consistent microscopic
calculations are compared with available experimental data. The model predicts
the location of the proton drip-line, the properties of proton emitters beyond
the drip-line, and provides information about the deformed single-particle
orbitals occupied by the odd valence proton.Comment: 9 pages, RevTeX, 3 PS figures, submitted Phys. Rev. Letter
Valuing informal carers' quality of life using best-worst scaling-Finnish preference weights for the Adult Social Care Outcomes Toolkit for carers (ASCOT-Carer)
This study developed Finnish preference weights for the seven-attribute Adult Social Care Outcomes Toolkit for carers (ASCOT-Carer) and investigated survey fatigue and learning in best-worst scaling (BWS) experiments. An online survey that included a BWS experiment using the ASCOT-Carer was completed by a sample from the general population in Finland. A block of eight BWS profiles describing different states from the ASCOT-Carer were randomly assigned to each respondent, who consecutively made four choices (best, worst, second best and second worst) per profile. The analysis panel data had 32,160 choices made by 1005 respondents. A scale multinomial logit (S-MNL) model was used to estimate preference weights for 28 ASCOT-Carer attribute levels. Fatigue and learning effects were examined as scale heterogeneity. Several specifications of the generalised MNL model were employed to ensure the stability of the preference estimates. The most and least-valued states were the top and bottom levels of the control over daily life attribute. The preference weights were not on a cardinal scale. We observed the position effect of the attributes on preferences associated with the best or second-best choices. A learning effect was found. The established preference weights can be used in evaluations of the effects of long-term care services and interventions on the quality of life of service users and caregivers. The learning effect implies a need to develop study designs that ensure equal consideration to all profiles (choice tasks) in a sequential choice experiment
Beta decay of 71,73Co; probing single particle states approaching doubly magic 78Ni
Low-energy excited states in 71,73Ni populated via the {\beta} decay of
71,73Co were investigated in an experiment performed at the National
Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU).
Detailed analysis led to the construction of level schemes of 71,73Ni, which
are interpreted using systematics and analyzed using shell model calculations.
The 5/2- states attributed to the the f5/2 orbital and positive parity 5/2+ and
7/2+ states from the g9/2 orbital have been identified in both 71,73Ni. In 71Ni
the location of a 1/2- {\beta}-decaying isomer is proposed and limits are
suggested as to the location of the isomer in 73Ni. The location of positive
parity cluster states are also identified in 71,73Ni. Beta-delayed neutron
branching ratios obtained from this data are given for both 71,73Co.Comment: Accepted for publication in PR
Double-magic nature of 132Sn and 208Pb through lifetime and cross-section measurements
Single-neutron states in Sn133 and Pb209, which are analogous to single-electron states outside of closed atomic shells in alkali metals, were populated by the (Be9, Be8) one-neutron transfer reaction in inverse kinematics using particle-Îł coincidence s
Magnetic moments of 2 1 + states in 124,126,128 Sn
The g factors of the first-excited states of stable 124Sn and radioactive 126,128Sn were measured by the recoil-in-vacuum method with comparatively high precision. The experiments were performed at the Holifield Radioactive Ion Beam Facility by Coulomb e
Orbital dependent nucleonic pairing in the lightest known isotopes of tin
By studying the 109Xe-->105Te-->101Sn superallowed alpha-decay chain, we
observe low-lying states in 101Sn, the one-neutron system outside doubly magic
100Sn. We find that the spins of the ground state (J = 7=2) and first excited
state (J = 5=2) in 101Sn are reversed with respect to the traditional level
ordering postulated for 103Sn and the heavier tin isotopes. Through simple
arguments and state-of-the-art shell model calculations we explain this
unexpected switch in terms of a transition from the single-particle regime to
the collective mode in which orbital-dependent pairing correlations, dominate.Comment: 5 pages 3 figure
High-precision B(E2) measurements of semi-magic Ni 58,60,62,64 by Coulomb excitation
High-precision reduced electric-quadrupole transition probabilities B(E2;01+→21+) have been measured from single-step Coulomb excitation of semi-magic Ni58,60,62,64 (Z=28) beams at 1.8 MeV per nucleon on a natural carbon target. The energy loss of the
Electromagnetic properties of the 21+ state in 134Te: Influence of core excitation on single-particle orbits beyond 132Sn
The g factor and B(E2) of the first excited 2+ state have been measured following Coulomb excitation of the neutron-rich semimagic nuclide 134Te (two protons outside 132Sn) produced as a radioactive beam. The precision achieved matches related g-factor m
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