67 research outputs found
Novel technique for constraining r-process (n,) reaction rates
A novel technique has been developed, which will open exciting new
opportunities for studying the very neutron-rich nuclei involved in the
r-process. As a proof-of-principle, the -spectra from the -decay
of Ga have been measured with the SuN detector at the National
Superconducting Cyclotron Laboratory. The nuclear level density and
-ray strength function are extracted and used as input to
Hauser-Feshbach calculations. The present technique is shown to strongly
constrain the Ge()Ge cross section and reaction rate.Comment: 5 pages, 3 figure
High-Precision Measurement of the 19Ne Half-Life and Implications for Right-Handed Weak Currents
We report a precise determination of the 19Ne half-life to be s. This result disagrees with the most recent precision
measurements and is important for placing bounds on predicted right-handed
interactions that are absent in the current Standard Model. We are able to
identify and disentangle two competing systematic effects that influence the
accuracy of such measurements. Our findings prompt a reassessment of results
from previous high-precision lifetime measurements that used similar equipment
and methods.Comment: 5 pages and 5 figures. Paper accepted for publication in Phys. Rev.
Let
Ground State Electromagnetic Moments of <sup>37</sup>Ca
The hyperfine coupling constants of neutron deficient Ca were deduced from the atomic hyperfine spectrum of the transition in Ca II, measured using the collinear laser spectroscopy technique. The ground-state magnetic-dipole and spectroscopic electric-quadrupole moments were determined for the first time as and fm, respectively. The experimental values agree well with nuclear shell model calculations using the universal sd model-space Hamiltonians versions A and B (USDA/B) in the -model space with a 95\% probability of the canonical nucleon configuration. It is shown that the magnetic moment of Ca requires a larger non--shell component than that of Ca for good agreement with the shell-model calculation, indicating a more robust closed sub-shell structure of Ca at the neutron number = 16 than Ca. The results are also compared to valence-space in-medium similarity renormalization group calculations based on chiral two- and three-nucleon interactions
β-decay Half-lives of Neutron-rich Nuclides in the A = 100 – 110 Mass Region
β-decay half-lives of neutron-rich nuclides in the A = 100–110 mass region have been measured using an implantation station installed inside of the Summing NaI(Tl) (SuN) detector at the National Superconducting Cyclotron Laboratory. Accurate half-lives for these nuclides are important for nuclear astrophysics, nuclear structure, and nuclear technology. The half-lives from the present work are compared with previous measurements, showing overall good agreement
High-precision half-life and branching-ratio measurements for superallowed Fermi β \u3csup\u3e+\u3c/sup\u3e emitters at TRIUMF - ISAC
A program of high-precision half-life and branching-ratio measurements for superallowed Fermi β emitters is being carried out at TRIUMF\u27s Isotope Separator and Accelerator (ISAC) radioactive ion beam facility. Recent half-life measurements for the superallowed decays of 14O, 18Ne, and 26Alm, as well as branching-ratio measurements for 26Alm and 74Rb are reported. These results provide demanding tests of the Standard Model and the theoretical isospin symmetry breaking (ISB) corrections in superallowed Fermi β decays. © Owned by the authors, published by EDP Sciences, 2014
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