Rutgers

[paper] Structure of the Sr-Zr isotopes near and at the magic N=50 shell from g-factor and lifetime measurements in8840Zr and 84,86,8838Sr

Structure of the Sr-Zr isotopes near and at the magic N=50 shell from g-factor and lifetime measurements in8840Zr and 84,86,8838Sr

G. Kumbartzki et al.

doi: 10.1103/PhysRevC.85.044322

Background: The evolution of and interplay between single-particle and collective excitations in the 40 ⩽N⩽ 50 range for 38Sr and 40Zr isotopes have been studied.

Purpose: Measurement of the g factor of the 21+ and 41+ states in radioactive 88Zr while simultaneously remeasuring the g(21+) factors in the Sr isotopes and extention of the measurements to higher energy states in the Sr isotopes. Lifetimes of states in these nuclei are determined.

Methods: The transient field technique in inverse kinematics and line-shape analysis using the Doppler-shift attenuation method are applied. The 88Zr nuclei were produced by the transfer of an α particle from the 12C nuclei of the target to 84Sr nuclei in the beam. The excited states in the stable 84Sr isotopes were simultaneously populated via Coulomb excitation by 12C in the same target. Coulomb excitation measurements on 86,88Sr were carried out with the same apparatus.

Results: The resulting g factors and B(E2) values of these nuclei reveal similarities between the two chains of Zr and Sr isotopes. Large-scale shell-model calculations were performed within the p3/2, f5/2, p1/2, g9/2 orbital space for both protons and neutrons and yielded results in agreement with the experimental data.

Conclusions: In this paper the magnetic moments and lifetimes of several low-lying states in 88Zr and 84,86,88Sr have been measured and compared to large-scale shell-model calculations.

[paper] Measurement of the 96Ru g(41+) factor and its nuclear structure interpretation

Measurement of the 96Ru g(41+) factor and its nuclear structure interpretation

D.A. Torres et al.

doi: 10.1103/PhysRevC.85.017305

Background: The experimental study of g(I>2) factors of nuclear states can provide information about the evolution of collectivity in certain regions of the nuclear chart, and assist in obtaining a microscopic description of the nuclear wave functions. The measurements and explanations of g(I>2) factors are still a challenge for experiments and theory.

Purpose: Measurement of the g(21+) and g(41+) factors, the latter for the first time, in the 9644Ru nucleus. Comparison of the experimental results with calculations using the shell model and collective models.

Methods: The experiments made use of the transient field technique, using a Coulomb-excitation reaction in inverse kinematics. Large scale shell model calculations were performed; comparisons with previous theoretical predictions, using the tidal-wave model and the hydrodynamical model, were carried out.

Results: The values of g(21+)=+0.46(2) and g(41+)=+0.58(8) were experimentally obtained. While the g(21+) value agrees with the hydrodynamical model prediction of g=Z/A=+0.46, the g(41+) is in agreement with the shell model predictions. The trend of the experimental g factors, as a function of nuclear spin, is not reproduced by the theoretical models discussed.

Conclusions: Measurements of g(21+) and g(41+) in 96Ru were performed. Further theoretical efforts are necessary to explain the trend of the g factors as a function of nuclear spin for the 96Ru nucleus. Future measurements of g(41+) should reduce the uncertainty of the result.

[paper] First g-factor measurements of the 21+ and the 41+ states of radioactive 100Pd

First g-factor measurements of the 21+ and the 41+ states of radioactive 100Pd

D.A. Torres et al.

doi: 10.1103/PhysRevC.84.044327

The g factors of the first 2+ and 4+ states of the radioactive 100Pd nucleus have been investigated for the first time, using an α-particle transfer reaction from 12C to 96Ru. The transient magnetic field technique in inverse kinematics was used. The 10046Pd54 nucleus is a suitable candidate for studying single-particle proton and neutron effects in the nuclear wave functions near the N=Z=50 shell closures. The results are discussed within the frameworks of both large-scale shell-model calculations and collective-model predictions.