β-Decay schemes of very neutron-rich sodium isotopes and their descendants

Guillemaud‐Mueller, D.; Détraz, C.; Langevin, M.; Naulin, F.; Saint-Simon, M. de; Thibault, C.; Touchard, F.; Epherre, M.

doi:10.1016/0375-9474(84)90064-2

Cited by 296 publications

(164 citation statements)

References 20 publications

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“…Measurements of γ decays and determination of the neutron separation energy were achieved in a thermal neutron capture on 26 Mg experiment [20]. Studies of the β decay of 27 Na were achieved from the fragmentation of iridium and uranium targets by protons to measure γ decays, β-γ-γ coincidences, and absolute intensities [21,22].…”

Section: Introductionmentioning

confidence: 99%

High-spin states in Al29 and Mg27

Dungan¹,

Tabor²,

Lubna³

et al. 2016

Phys. Rev. C

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The structure of 29 Al and 27 Mg was investigated using the reactions 18 O( 14 C,p2n) and 18 O( 14 C,α n) at 40 MeV. The charged particles were detected and identified with a ∆E-E telescope in coincidence with γ radiation detected in the Florida State University (FSU) Compton suppressed γ detector array. The level and decay schemes of both nuclei have been expanded at higher spins and excitation energies. The positive-parity states up to 3.5 to 4.5 MeV agree well with shell model calculations using the USDA interaction. The negative-parity states in 27 Mg are reproduced relatively well by one-particle-hole calculations with the WBP-a interaction. Three 27 Mg states unbound by 0.4 to 1.4 MeV to neutron decay were observed to decay radiatively. One of these states had been previously observed to γ decay in a (d,pγ) experiment along with a surprising 16 other neutron unbound states. The competition between neutron and gamma decay in these states is discussed in terms of angular momentum barriers and spectroscopic factors.

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Section: Introductionmentioning

confidence: 99%

High-spin states in Al29 and Mg27

Dungan¹,

Tabor²,

Lubna³

et al. 2016

Phys. Rev. C

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“…On the other hand, the magnetic moment of 79 Ga is about two times lower than the one of 71,75,77 Ga, and the quadrupole moment of 71,79 Ga is positive while the one of 75,77 Ga is negative. All these results are explained if the three-proton configuration of these 3/2 − states evolves as a function of the number of neutrons occupying the νg 9/2 subshell, from [πp 3 48 . It is worth noting that the latter configuration, with I π = 5/2 − , was suggested for the ground state of 81 Ga 50 [12] and confirmed by the last measurement [11].…”

Section: Introductionmentioning

confidence: 99%

“…[1]). Several magic shell gaps are so fragile as several neutron-rich nuclei ( 12 Be 8 , 32 Mg 20 , and 42 Si 28 ) were found to exhibit large collectivity [2][3][4]. As for 78 28 Ni 50 , the two magic numbers, 28 and 50, are created by spin-orbit interaction, such as 6, 14 or 82.…”

Section: Introductionmentioning

confidence: 99%

Medium-spin states in neutron-rich83As and81As

et al. 2011

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The 83, 81 As nuclei have been produced as fission fragments in the fusion reaction 18 O+ 208 Pb at 85 MeV bombarding energy and studied with the Euroball array. Medium-spin states of 83,81 As have been established up to ∼ 3.5 MeV excitation energy. From angular correlation analysis, spin values have been assigned to most of the 81 As excited states. The behaviors of the yrast structures identified in this work are discussed in comparison with the general features known in the mass region. Then they are compared to the results of two theoretical approaches, the 'rotor+quasi-particle' for 81 As and the shell model using the effective interactions JUN45 for 83,81 As.

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“…The breakdown of the N = 20 shell gap was observed through the low excitation energy of the 2 + state in 32 Mg [2]. Much effort has been devoted since then to the study of level schemes in attempting to understand this.…”

mentioning

confidence: 99%

“…The carbon target thickness was 4.046 g/cm 2 while that of the (CH 2 ) n target was 3.988 g/cm 2 . Two other thicknesses of carbon targets, namely 2.523 and 7.062 g/cm 2 , were used for the 33 Mg beam to check if there is any loss due to multiple scattering in deriving the interaction cross sections.…”

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confidence: 99%

Matter radii of32−35Mg

Kanungo¹,

Procházka²,

Horiuchi³

et al. 2011

Phys. Rev. C

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The interaction cross sections of [32][33][34][35] Mg at 900A MeV have been measurmed using the fragment separator at GSI. The deviation from the r 0 A 1/3 trend is slightly larger for 35 Mg, signaling the possible formation of a longer tail in the neutron distribution for 35 Mg. The radii extracted from a Glauber model analysis with Fermi densities are consistent with models predicting the development of neutron skins. The shell structure of nuclei has formed a fundamental basis for understanding their properties. As nuclei accumulate a large excess of neutrons, the conventional shell structure starts to show signs of mutation. Investigations of ground-state properties of neutron-rich nuclei are a key toward the search for the effects leading to the breakdown of the conventional shell structure. The matter radii of neutron-rich nuclei are one of the fundamental properties that constrain nuclear wave functions and carry crucial information on deformation, shell effects, and formation of neutron skins and halos [1].In this Rapid Communication we report on the first determination of the matter radii of [33][34][35] Mg in the N = 20 island of inversion from a measurement of the interaction cross section. The results are consistent with development of neutron skins with 35 Mg showing the possibility of a longer density tail.The breakdown of the N = 20 shell gap was observed through the low excitation energy of the 2 + state in 32 Mg [2]. Much effort has been devoted since then to the study of level schemes in attempting to understand this. The large B(E2) values deduced from the Coulomb excitation * ritu@triumf.ca measurements [3,4] were suggestive of 32 Mg being a deformed nucleus. It should be noted here that the extraction of the deformation value (β) in [3] is obtained under the assumption of a collective model. For a proper understanding of deformation in these nuclei, measured radii are important.The level scheme of 32 Mg from β delayed γ spectroscopy of 32 Na [5] suggests that 32 Mg is not an axially symmetric rotor. It is not a vibrational nucleus either. It was in fact discussed [6], based on a Skyrme-Hartree-Fock description, that this nucleus probably exhibits γ unstable deformation. A relativistic mean-field (RMF) calculation with three-dimensional angular momentum projection involving triaxial degrees of freedom [7] gives a ground state having β = 0.6 and γ = 10 • . Density and radii from such models would be useful for comparison with the present data. Recently, a shape coexistent 0 + state has been found in 32 Mg [8].The Monte Carlo shell model (MCSM) [9] has been considered to be fairly well suited to describe the levels in nuclei around the island of inversion. The predicted level scheme of 32 Mg also does not show features of an axially symmetric rotor.Mean-field models based on the Hartree-Fock (HF) or Hartree-Fock-Bogoliubov (HFB) approximations have been developed by several groups [10][11][12] for the neutron-rich 021302-1 0556-2813/2011/83(2)/021302(4)

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β-Decay schemes of very neutron-rich sodium isotopes and their descendants

Cited by 296 publications

References 20 publications

High-spin states in Al29 and Mg27

High-spin states in Al29 and Mg27

Medium-spin states in neutron-rich83As and81As

Matter radii of32−35Mg

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