The p((11)Li, (9)Li)t reaction has been studied for the first time at an incident energy of 3A MeV at the new ISAC-2 facility at TRIUMF. An active target detector MAYA, built at GANIL, was used for ...the measurement. The differential cross sections have been determined for transitions to the (9)Li ground and first excited states in a wide range of scattering angles. Multistep transfer calculations using different (11)Li model wave functions show that wave functions with strong correlations between the halo neutrons are the most successful in reproducing the observation.
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The collective structure of 106Cd is elucidated by multi-step Coulomb excitation of a 3.849 MeV/A beam of 106Cd on a 1.1 mg/cm2208Pb target using GRETINA-CHICO2 at ATLAS. Fourteen E2 matrix elements ...were obtained. The nucleus 106Cd is a prime example of emergent collectivity that possesses a simple structure: it is free of complexity caused by shape coexistence and has a small, but collectively active number of valence nucleons. This work follows in a long and currently active quest to answer the fundamental question of the origin of nuclear collectivity and deformation, notably in the cadmium isotopes. The results are discussed in terms of phenomenological models, the shell model, and Kumar-Cline sums of E2 matrix elements. The 〈02+||E2||21+〉 matrix element is determined for the first time, providing a total, converged measure of the electric quadrupole strength, 〈Q2〉, of the first-excited 21+ level relative to the 01+ ground state, which does not show an increase as expected of harmonic and anharmonic vibrations. Strong evidence for triaxial shapes in weakly collective nuclei is indicated; collective vibrations are excluded. This is contrary to the only other cadmium result of this kind in 114Cd by C. Fahlander et al. (1988) 38, which is complicated by low-lying shape coexistence near midshell.
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Electric quadrupole moments provide a direct insight on the single-particle structure or the collective nature of a nuclear state. This article presents a short review on some of the experimental ...methods available to measure quadrupole moments with emphasis on the reorientation technique in Coulomb excitation and its use in combination with radioactive ion beams.
The availability of good quality radioactive ion beams is allowing unique research in nuclear physics and nuclear astrophysics. Coulomb Excitation is a mechanism with a relatively large cross ...sections that allows the use of low intensity radioactive ion beams, and therefore it has become in a powerful experimental tool for the study of nuclei consirderably far from stability. Among the data of interest for nuclear models that can be obtained using Coulomb excitation are: reduced transition probabilities; electric quadrupole moments; and magnetic moments. This work gives an overview of experimental studies on the mass 80 region in which I have been involved.
Spectroscopic data, such as precise γ-ray branching and E2/M1 multipole-mixing ratios, provide vital constraints when performing multi-dimensional Coulomb-excitation analyses. Consequently, as part ...of our new Coulomb-excitation campaign aimed at investigating the role of exotic non-axial (triaxial) deformations in the unstable refractory Ru-Mo isotopes, additional beta-decay data was obtained. These measurements make use of ANL's CARIBU facility, which provides intense beams of radioactive refractory isotopes along with the excellent efficiency and angular resolution of the GRETINA γ-ray tracking array. In this article, we report on the analysis of the A = 110 decay chain, focussing on the identification of previously unreported states in 110Ru following the decay of 110Tc.
Proton inelastic scattering off a neutron halo nucleus, 11Li, has been studied in inverse kinematics at the IRIS facility at TRIUMF. The aim was to establish a soft dipole resonance and to obtain its ...dipole strength. Using a high quality 66 MeV 11Li beam, a strongly populated excited state in 11Li was observed at Ex=0.80±0.02 MeV with a width of Γ=1.15±0.06 MeV. A DWBA (distorted-wave Born approximation) analysis of the measured differential cross section with isoscalar macroscopic form factors leads us to conclude that this observed state is excited in an electric dipole (E1) transition. Under the assumption of isoscalar E1 transitions, the strength is evaluated to be extremely large amounting to 30∼296 Weisskopf units, exhausting 2.2%∼21% of the isoscalar E1 energy-weighted sum rule (EWSR) value. The large observed strength originates from the halo and is consistent with the simple di-neutron model of 11Li halo.
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The 38th edition of the Symposium on Nuclear Physics was held at Hotel Hacienda Cocoyoc, Morelos, Mexico from January 6–9, 2015. As in previous years, the Symposium brought together leading ...scientists from all around the world, working on: nuclear structure, nuclear reactions, physics with radioactive ion beams, hadronic physics, nuclear astrophysics, neutron physics and relativistic heavy-ion physics. The scientific program consisted of 27 invited talks, proposed by the international advisory committee that covered, in a balanced way, the experimental and theoretical work that currently is undergoing in the research fields of the Symposium. Ten posters complemented the program, providing students with an opportunity to bring their work to the attention of visiting scientists. This year, the conference activities also included a special talk presented by Archaeologist Omar Espinosa Severino about the ancient ruins found in Chalcatzingo, a village located approximately a 40 minute drive from the conference venue. The talk was followed by a visit to the archaeological site, guided by the group led by Archaeologist Mario Cordova Tello. The present volume contains 14 research articles based on invited talks presented at the Symposium. I would like to thank all the authors for their enthusiastic contribution. Special thanks to the anonymous referees for the time devoted to the review process, their input helped to maintain a high standard of the Conference Proceedings. Finally I would also like to thank the Symposiums' International Advisory Committee and the Sponsoring Organizations that made this event possible.
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