scholarly journals Low-Energy Coulomb Excitation for the Shell Model

Physics ◽  
2021 ◽  
Vol 3 (4) ◽  
pp. 1237-1253
Author(s):  
Marco Rocchini ◽  
Magda Zielińska

Low-energy Coulomb excitation is capable of providing unique information on static electromagnetic moments of short-lived excited nuclear states, including non-yrast states. The process selectively populates low-lying collective states and is, therefore, ideally suited to study phenomena such as shape coexistence and the development of exotic deformation (triaxial or octupole shapes). Historically, these experiments were restricted to stable isotopes. However, the advent of new facilities providing intense beams of short-lived radioactive species has opened the possibility to apply this powerful technique to a much wider range of nuclei. The paper discusses the observables that can be measured in a Coulomb-excitation experiment and their relation to the nuclear structure parameters with an emphasis on the nuclear shape. Recent examples of Coulomb-excitation studies that provided outcomes relevant for the Shell Model are also presented.

Author(s):  
Marco Rocchini ◽  
Magda Zielińska

Low-energy Coulomb excitation is capable of providing unique information on static electromagnetic moments of short-lived excited nuclear states, including non-yrast states. The process selectively populates low-lying collective states and is therefore ideally suited to study phenomena such as shape coexistence and development of exotic deformation (triaxial or octupole shapes). Historically, these experiments were restricted to stable isotopes. However, the advent of new facilities providing intense beams of short-lived radioactive species has opened the possibility to apply this powerful technique to a much wider range of nuclei. We discuss the observables that can be measured in a Coulomb-excitation experiment, their relation to nuclear structure parameters with an emphasis on the nuclear shape, and present some recent examples of Coulomb-excitation studies that provided outcomes relevant for the Shell Model.


2018 ◽  
Vol 178 ◽  
pp. 02014
Author(s):  
Magda Zielińska ◽  
Katarzyna Hadyńska-Klȩk

Coulomb excitation is one of the rare methods available to obtain information on static electromagnetic moments of short-lived excited nuclear states, including collective non-yrast levels. It is thus an ideal tool to study shape coexistence and shape evolution throughout the nuclear chart. Historically, these experiments were limited to stable isotopes, however the advent of new facilities, providing intense beams of short-lived radioactive species, has opened the possibility to apply this powerful technique to a much wider range of nuclei. Here, we present some recent complex Coulomb-excitation studies and use the example of superdeformed states in 42Ca to demonstrate the sensitivity of the method to second-order effects such as relative signs of electromagnetic matrix elements and quadrupole moments.


2006 ◽  
Vol 15 (07) ◽  
pp. 1505-1512 ◽  
Author(s):  
◽  
G. GEORGIEV ◽  
I. STEFANESCU ◽  
D. L. BALABANSKI ◽  
P. BUTLER ◽  
...  

We report on the first use of post-accelerated radioactive isomeric beams. Long-lived isomeric states in 68 Cu and 70 Cu have been produced and separated at ISOLDE, CERN. Subsequently they were post-accelerated to 2.86 MeV/u and sent to a target in the center of the MINIBALL spectrometer, used for the detection of the γ-rays of interest. The preliminary results from the Coulomb excitation of the Iπ=6-, 1+ states in 68 Cu and the Iπ=6- one in 70 Cu , compared to a large-scale shell model calculations, hint the importance of the excitations across the Z=28 gap for the understanding of the nuclear structure in the neutron-rich N=40 region.


2006 ◽  
Vol 15 (07) ◽  
pp. 1495-1503
Author(s):  
◽  
PIETER DOORNENBAL

The RISING fast beam campaign aims at high resolution γ-ray spectroscopy experiments with relativistic radioactive beams at GSI. The secondary beams produced by fragmentation or fission are used for Coulomb excitation or secondary fragmentation experiments to perform studies of nuclei far off stability. The physics phenomena studied with this method include nuclear structure experiments targeting at the evolution of shell structure toward the drip lines, mirror symmetry, collectivity and electromagnetic transition strengths. Example results of this fast beam campaign are presented and compared to various shell model calculations and nuclear structure models.


1995 ◽  
Vol 48 (5) ◽  
pp. 813 ◽  
Author(s):  
FC Barker

Recent fits to low-energy 7Li(p, "Yo)8Be angular distribution and analysing power data suggested a large p-wave strength. It is shown that acceptable fits to the data can be obtained by attributing the p-wave Ml contributions to the tails of the 17 �64 and 18 �15 MeV 1+ levels of 8Be, with p-wave strengths much less than those obtained previously, but only if some of the spectroscopic amplitudes have signs opposite to those suggested by shell model calculations and/or a fit to higher-energy data.


1982 ◽  
Vol 35 (3) ◽  
pp. 301 ◽  
Author(s):  
FC Barker

The contribution to the Coulomb excitation of the first excited state of 170 due to virtual excitation of the giant dipole resonance (GDR) is calculated, using shell model wavefunctions for the ground and first excited states. A large value is obtained.


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