PRC

[paper] Perturbed angular distributions with LaBr3 detectors: The $g$ factor of the first 10$^+$ state in $^{110}$Cd reexamined

Perturbed angular distributions with LaBr3  detectors: The g factor of the first 10+  state in 110Cd reexamined

T.J. Gray et al.

doi: 10.1103/PhysRevC.96.054332

The time differential perturbed angular distribution technique with LaBr3 detectors has been applied to the Iπ=11/2 isomeric state (Ex = 846 keV, τ=107 ns) in 107Cd, which was populated and recoil-implanted into a gadolinium host following the 98Mo(12C, 3n)107Cd reaction. The static hyperfine field strength of Cd recoil implanted into gadolinium was thus measured, together with the fraction of nuclei implanted into field-free sites, under similar conditions as pertained for a previous implantation perturbed angular distribution
g-factor measurement on the Iπ=10+ state in 110Cd. The 110Cd g(10+) value was thereby reevaluated, bringing it into agreement with the value expected for a seniority-two νh11/2 configuration.

[paper] Prediction and evaluation of magnetic moments in T=1/2, 3/2, and 5/2 mirror nuclei

Prediction and evaluation of magnetic moments in T=1/2, 3/2, and 5/2 mirror nuclei

Theo J. Mertzimekis

doi: 10.1103/PhysRevC.94.064313

The Buck-Perez analysis of mirror nuclei magnetic moments has been applied on an updated set of data for T=1/2,3/2 mirror pairs and attempted for the first time for T=5/2 nuclei. The spin expectation value for mirror nuclei up to mass A=63 has been reexamined. The main purpose is to test Buck-Perez analysis effectiveness as a prediction and—more importantly—an evaluation tool of magnetic moments in mirror nuclei. In this scheme, ambiguous signs of magnetic moments are resolved, evaluations of moments with multiple existing measurements have been performed, and a set of predicted values for missing moments, especially for several neutron-deficient nuclei is produced. A resolution for the case of the 57Cu ground-state magnetic moment is proposed. Overall, the method seems to be promising for future evaluations and planning future measurements.

[paper] Magnetic moment of the 13/2+ isomeric state in 69Cu: Spin alignment in the one-nucleon removal reaction

Magnetic moment of the 13/2+ isomeric state in 69Cu: Spin alignment in the one-nucleon removal reaction

A. Kusoglu et al.

doi: http://dx.doi.org/10.1103/PhysRevC.93.054313

We report on a new measurement of the g factor of the (13/2+) isomeric state in the neutron-rich nucleus 69Cu. This study demonstrates the possibility of obtaining considerable nuclear spin alignment for multi-quasiparticle states in single-nucleon removal reactions. The time-dependent perturbed angular distribution (TDPAD) method was used to extract the gyromagnetic factor of the (13/2+) [T½=351(14) ns] isomeric state of 69Cu. Its g factor was obtained as g(13/2+)=0.248(9). The experimentally observed spin alignment for the state of interest was deduced as A=−3.3(9)%.

[Paper] Magnetic moments in odd-A Cd isotopes and coupling of particles with zero-point vibrations

Magnetic moments in odd-A Cd isotopes and coupling of particles with zero-point vibrations

S. Mishev and V. V. Voronov

DOI: 10.1103/PhysRevC.92.044329

Background: The coupling of the last nucleon with configurations in the ground state of the even-even core is known to augment the single quasiparticle fragmentation pattern. In a recent experimental study by Yordanov et al. the values of the magnetic dipole and electric quadrupole moments of the 11/2 state in a long chain of Cd isotopes were found to follow a simple trend which we try to explain by means of incorporating long-range correlations in the ground state.

Purpose: Our purpose is to study the influence of ground-state correlations (GSCs) on the magnetic moments and compare our results with the data for the odd-A Cd isotopes.

Method: In order to evaluate if the additional correlations have bearing on the magnetic moments we employ an extension to the quasiparticle-phonon model (QPM) which takes into account quasiparticle⊗phonon configurations in the ground state of the even-even core affecting the structure of the odd-A nucleus wave function.

Results: It is shown that the values for the magnetic moments which the applied QPM extension yields deviate further from the Schmidt values. The latter is in agreement with the measured values for the Cd isotopes.

Conclusions: The GSCs exert significant influence on the magnetic dipole moments and reveal a potential for reproducing the experimental values for the studied cadmium isotopes.

[Paper] Investigation into the semimagic nature of the tin isotopes through electromagnetic moments

Investigation into the semimagic nature of the tin isotopes through electromagnetic moments

J.M. Allmond et al.

DOI: 10.1103/PhysRevC.92.041303

A complete set of electromagnetic moments, B(E2;0+1→2+1),Q(2+1), and g(2+1), have been measured from Coulomb excitation of semi magic 112,114,116,118,120,122,124Sn (Z=50) on natural carbon and titanium targets. The magnitude of the B(E2) values, measured to a precision of ∼4%, disagree with a recent lifetime study [Phys. Lett. B 695, 110 (2011)] that employed the Doppler-shift attenuation method. The B(E2) values show an overall enhancement compared with recent theoretical calculations and a clear asymmetry about midshell, contrary to naive expectations. A new static electric quadrupole moment, Q(2+1), has been measured for 114Sn. The static quadrupole moments are generally consistent with zero but reveal an enhancement near midshell; this had not been previously observed. The magnetic dipole moments are consistent with previous measurements and show a near monotonic decrease in value with neutron number. The g-factor measurements in 112,114Sn establish the recoil-in-vacuum method for states with τ∼0.5 ps and hence demonstrate that this method can be used for future g-factor measurements on proton-rich isotopes toward 100Sn. Current theory calculations fail to reproduce the electromagnetic moments of the tin isotopes. The role of 2p-2h and 4p-4h intruders, which are lowest in energy at midshell and outside of current model spaces, needs to be investigated in the future.

[paper] Gamow-Teller transitions and magnetic moments using various interactions

Gamow-Teller transitions and magnetic moments using various interactions

Ricardo Garcia and Larry Zamick

doi: 10.1103/PhysRevC.92.034322

In a single j-shell calculation we consider the effects of several different interactions on Gamow-Teller B(GT) values and magnetic moments. The interactions used are MBZE, J=0 pairing, Jmax pairing, and half and half. Care is taken when there are isospin crossings and/or degeneracies.

[paper] Structural evolution in transitional nuclei of mass 82≤A≤132

Structural evolution in transitional nuclei of mass 82≤A≤132

M. Bhutan

doi: 10.1103/PhysRevC.92.034323

In this theoretical study, we report an investigation on the behavior of two-neutron separation energy, a differential variation of the nucleon separation energy, the nuclear charge radii, and the single-particle energy levels along the isotopic chains of transitional nuclei. We have used the relativistic mean-field formalism with NL3 and NL3* forces for this present analysis. The study refers to the even-even nuclei such as Zr, Mo, Ru, and Pd for N=42−86, where a rich collective phenomena such as proton radioactivity, cluster or nucleus radioactivity, exotic shapes, island of inversion, etc. are observed. We found that there are few nonmonotonic aspects over the isotopic chain, which are correlated with the structural properties such as shell/subshell closures, the shape transition, clustering, magicity, etc. In addition to these, we have shown the internal configuration of these nuclei to get a further insight into the reason for these discrepancies.

[paper] Hyperfine structure anomaly and magnetic moments of neutron deficient Tl isomers with I=9/2

Hyperfine structure anomaly and magnetic moments of neutron deficient Tl isomers with I=9/2

A.E. Barzakh et al.

doi: 10.1103/PhysRevC.86.014311

The hyperfine structure of 276.9-nm atomic transition has been studied by the resonant ionization spectroscopy method at mass-separator IRIS (Investigation of Radioactive Isotopes on Synchrocyclotron), Petersburg Nuclear Physics Institute (PNPI) for the odd Tl isomers with I=9/2 and A=187–197. A differential hyperfine structure anomaly for 6p2P1/2 and 7s2S1/2 atomic states in Tl isomers with I=9/2 has been determined. It is described by the recently developed theoretical approach fairly well. This enables one to recalculate the magnetic moments of 187−193Tlm(I=9/2) from previously measured hyperfine splittings for 7s2S1/2 states and to determine for the first time the magnetic moments for 197Tlm and 195Tlm(I=9/2) from hyperfine splittings for 6p2P1/2 states with properly taking into account the rather great hyperfine structure anomaly. Similar measurements with greater accuracy have been proposed for the other nuclear states in odd-odd Tl isotopes. These measurements could shed light on the nuclear magnetization distribution in these isotopes.

[paper] Self-consistent calculations of quadrupole moments of the first 2+ states in Sn and Pb isotopes

Self-consistent calculations of quadrupole moments of the first 2+ states in Sn and Pb isotopes

D. Voitenkov et al.

doi: 10.1103/PhysRevC.85.054319

A method of describing static moments of excited states and transitions between excited states is formulated for nonmagic nuclei within the Green’s function formalism. Quadrupole moments of the first 2+ states in tin and lead isotope chains are calculated self-consistently using the energy density functional by Fayans et al. [Nucl. Phys. A 676 49 (2000)]. Reasonable agreement with available experimental data is obtained. Quadrupole moments of unstable nuclei including 100Sn and 132Sn are predicted. A nontrivial dependence of the quadrupole moments on the neutron excess is found which can be traced to the negative proton contributions.

[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.