1,329 research outputs found
Search for Intrinsic Excitations in 152Sm
The 685 keV excitation energy of the first excited 0+ state in 152Sm makes it
an attractive candidate to explore expected two-phonon excitations at low
energy. Multiple-step Coulomb excitation and inelastic neutron scattering
studies of 152Sm are used to probe the E2 collectivity of excited 0+ states in
this "soft" nucleus and the results are compared with model predictions. No
candidates for two-phonon K=0+ quadrupole vibrational states are found. A 2+,
K=2 state with strong E2 decay to the first excited K=0+ band and a probable 3+
band member are established.Comment: 4 pages, 6 figures, accepted for publication as a Rapid Communication
in Physical Review
Inelastic Neutron Scattering Studies of \u3csup\u3e76\u3c/sup\u3eGe and \u3csup\u3e76\u3c/sup\u3eSe: Relevance to Elevance to Neutrinoless Double-β Decay
Inelastic neutron scattering measurements were performed at the University of Kentucky Accelerator Laboratory on enriched 76Ge and 76Se scattering samples. From measurements at incident neutron energies from 2.0 to 4.0 MeV, many new levels were identified and characterized in each nucleus; level lifetimes, transition probabilities, multipole mixing ratios, and other properties were determined. In addition, γ-ray cross sections for the 76Ge(n,n′γ) reaction were measured at neutron energies up to 5.0 MeV, with the goal of determining the cross sections of γ rays in 2040-keV region, which corresponds to the region of interest in the neutrinoless double β decay of 76Ge. Gamma rays from the three strongest branches from the 3952-keV level were observed, but the previously reported 2041-keV γ ray was not. Population cross sections across the range of incident neutron energies were determined for the 3952-keV level, resulting in a cross section of ~0.1 mb for the 2041-keV branch using the previously determined branching ratios. Beyond this, the data from these experiments indicate that previously unreported γ rays from levels in 76Ge can be found in the 2039-keV region
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
Emerging nuclear collectivity in Te
The emergence of nuclear collectivity near doubly-magic Sn was
explored along the stable, even-even Te isotopes. Preliminary
measurements of the transition strengths
are reported from Coulomb excitation experiments primarily aimed at measuring
the factors of the states. Isotopically enriched Te targets
were excited by 198-205 MeV Ni beams. A comparison of transition
strengths obtained is made to large-scale shell-model calculations with
successes and limitations discussed.Comment: 5 pages, 3 figures, Submitted to Proceedings HIAS 2019, EPJ Web of
Conference
Understanding Excitations in Co, Ni
High spin states in Co (), Ni () and Co have
been populated by the fusion evaporation reactions, Ti(C,
p2n)Co, Ti(C, 3n)Ni, and Ti(C,
p2n)Co. The 9 MV tandem accelerator at the John D Fox Laboratory,
Florida State University (FSU) was used to accelerate the C beam and the
de-exciting rays were detected by the FSU detector array consisting of
six High Purity Germanium (HPGe) clover detectors, and three single crystals.
Directional correlation of the rays de-exciting oriented states (DCO
ratios) and polarization asymmetry measurements helped to establish spin and
parities of the excited states whenever possible. The level scheme of Co
has been expanded with the inclusion of positive parity states up to 31/2
at around 11 MeV. The Ni positive parity states known from previous
study were verified with modifications to some of the spins and parities. On
the other hand, the negative parity states were extended to 31/2 at an
excitation energy of 12 MeV. No new transition was observed for Co, but
one of the major bands has been reassigned as consisting of positive parity
states by reason of this study which is a candidate for magnetic rotation band.
Cross shell excitations were observed in the three nuclei studied and the
prominent role of excitation to g orbital crossing the shell gap
was established in relation to collective excitation in these nuclei by
comparison with large-scale shell model calculations
Transient field g factor and mean-life measurements with a rare isotope beam of 126Sn
Background: The g factors and lifetimes of the 21+ states in the stable, proton-rich Sn isotopes have been measured, but there is scant information on neutron-rich Sn isotopes. Purpose: Measurement of the g factor and the lifetime of the 21+ state at 1.141 MeV in neutron-rich 126Sn (T1/2=2. 3×105y). Method: Coulomb excitation in inverse kinematics together with the transient field and the Doppler shift attenuation techniques were applied to a radioactive beam of 126Sn at the Holifield Radioactive Ion Beam Facility. Results: g(21+)=-0.25(21) and τ(21+)=1.5(2) ps were obtained. Conclusions: The data are compared to large-scale shell-model and quasiparticle random-phase calculations. Neutrons in the h11/2 and d3/2 orbitals play an important role in the structure of the 21+ state of 126Sn. Challenges, limitations, and implications for such experiments at future rare isotope beam facilities are discussed
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