Shell structure underlying the evolution of quadrupole collectivity in S-38 and S-40 probed by transient-field g-factor measurements on fast radioactive beams

Abstract

The shell structure underlying shape changes in neutron-rich nuclei between N=20 and N=28 has been investigated by a novel application of the transient field technique to measure the first-excited state g factors in S-38 and S-40 produced as fast radioactive beams. Details of the new methodology are presented. In both S-38 and S-40 there is a fine balance between the proton and neutron contributions to the magnetic moments. Shell model calculations which describe the level schemes and quadrupole properties of these nuclei also give a satisfactory explanation of the g factors. In S-38 the g factor is extremely sensitive to the occupation of the neutron p3/2 orbit above the N=28 shell gap as occupation of this orbit strongly affects the proton configuration. The g factor of deformed S-40 does not resemble that of a conventional collective nucleus because spin contributions are more important than usual.

10 pages, 36 figures, accepted for publication in Physical Review C

References in corpus (7)

• The Shell Model as Unified View of Nuclear Structure
• Spherical Shell Model description of rotational motion
• Shell Model Study of the Neutron-Rich Nuclei around N=28
• The N=28 shell closure; from N=Z to the neutron drip line
• Probing shell structure and shape changes in neutron-rich sulfur isotopes through transient-field g factor measurements on fast radioactive beams of 38S and 40S
• Intermediate energy Coulomb excitation as a probe of nuclear structure at radioactive beam facilities
• Shell-model test of the rotational-model relation between static quadrupole moments Q(2^+_1), B(E2)'s, and orbital M1 transitions

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• Shell model study for neutron-rich sd-shell nuclei
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• Apparatus for in-beam hyperfine interactions and $g$-factor measurements: design and operation
• Probing the $N=14$ subshell closure: $g$ factor of the ${}^{26}$Mg(2${}_1^{+}$) state
• Experimental Study of the ${}^{\text{38}}$S Excited Level Scheme
• Populating Low-Spin States in Radioactive Nuclei to Measure Magnetic Moments Using the Transient Field Technique