Total and partial photoneutron cross sections for Pb isotopes

Kondo, Takeo; Utsunomiya, H.; Goriely, Stéphane; Daoutidis, Ioannis; Iwamoto, Chihiro; Akimune, H.; Okamoto, A.; Yamagata, T.; Kamata, Masaki; Itoh, Osamu; Toyokawa, Hiroyuki; Lui, Y.‐W.; Harada, Hideo; Kitatani, Fumito; Hilaire, Stéphane; Koning, A. J.

doi:10.1103/physrevc.86.014316

Cited by 35 publications

(18 citation statements)

References 30 publications

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“…2, cross sections around the neutron threshold are rather well described by the D1M + QRPA model, although some deviations can be seen. The agreement around the neutron threshold is rather satisfactory and there is no reason to invoke the presence of extra low-lying strength from the present data, at least in the vicinity of the neutron threshold, as seen in some previous photodata [11,15,16,38]. In contrast, larger deviations are seen for the predictions obtained with the BSk7 + QRPA strength, in particular around 11 MeV, but also at lower energies in the 145,146 Nd cases.…”

Section: A Photoneutron Cross Sectionssupporting

confidence: 79%

Photoneutron cross sections for neodymium isotopes: Toward a unified understanding of(γ,n)and(n,γ)reactions in the rare earth region

et al. 2015

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Photoneutron cross sections were measured for five stable Nd isotopes, 143,144,145,146,148 Nd, near neutron threshold with highly monochromatic laser-Compton scattering γ rays. The photoneutron data were compared with the calculations performed with the TALYS reaction code with inputs of the Skyrme Hartree-Fock-Bogoliubov (HFB) plus quasi-particle random phase approximation (QRPA) model and the axially symmetric deformed Gogny HFB plus QRPA model of E1 γ -ray strength. Using the γ -ray strength function constrained by the present photoneutron data, a thorough analysis of the reverse (n,γ ) cross sections is made. Radiative neutron capture cross sections for an s-process branching-point nucleus in the rare earth region, 147 Nd with the half-life 10.98 d, are deduced with the γ -ray strength function method. The impact of the newly evaluated 147 Nd(n,γ ) 148 Nd cross section on s-process nucleosynthesis is discussed.

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Section: A Photoneutron Cross Sectionssupporting

confidence: 79%

Photoneutron cross sections for neodymium isotopes: Toward a unified understanding of(γ,n)and(n,γ)reactions in the rare earth region

et al. 2015

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“…2 is a detailed comparison of the experimentally observed E1 and M1 strength distributions against theoretical predictions from threephonon EDF+QPM calculations [23,24]. The faithful reproduction of the experimental data is fully consistent with earlier EDF+QPM calculations that successfully reproduced the experimental photoneutron cross sections-albeit in the GDR region-in 206 Pb, 207 Pb, and 208 Pb [46].…”

supporting

confidence: 73%

“…Thus, to complement the present low-energy experiment we rely on the measurements of the photoabsorption cross section for E γ > S 1n reported in Refs. [46,49]. Using the combined experimental information, we list in Table 2 a few moments of the experimental photoabsorption cross section.…”

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confidence: 99%

Pygmy and core polarization dipole modes in 206Pb: Connecting nuclear structure to stellar nucleosynthesis

et al. 2017

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A high-resolution study of the electromagnetic response of 206 Pb below the neutron separation energy is performed using a ( γ,γ ) experiment at the HI γS facility. Nuclear resonance fluorescence with 100% linearly polarized photon beams is used to measure spins, parities, branching ratios, and decay widths of excited states in 206 Pb from 4.9 to 8.1 MeV. The extracted ΣB(E1)↑ and ΣB(M1)↑ values for the total electric and magnetic dipole strength below the neutron separation energy are 0.9±0.2 e 2 fm 2 and 8.3 ± 2.0 µ 2 N , respectively. These measurements are found to be in very good agreement with the predictions from an energy-density functional (EDF) plus quasiparticle phonon model (QPM). Such a detailed theoretical analysis allows to separate the pygmy dipole resonance from both the tail of the giant dipole resonance and multi-phonon excitations. Combined with earlier photonuclear experiments above the neutron separation energy, one extracts a value for the electric dipole polarizability of 206 Pb of α D = 122 ± 10 mb/MeV. When compared to predictions from both the EDF+QPM and accurately calibrated relativistic EDFs, one deduces a range for the neutron-skin thickness of R 206 skin = 0.12-0.19 fm and a corresponding range for the slope of the symmetry energy of L = 48-60 MeV. This newly obtained information is also used to estimate the Maxwellian-averaged radiative cross section 205 Pb(n,γ) 206 Pb at 30 keV to be σ = 130±25 mb. The astrophysical impact of this measurement-on both the s-process in stellar nucleosynthesis and on the equation of state of neutron-rich matter-is discussed.

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“…Stimulated by the advent of new radioactive beam facilities, a large amount of research has been devoted in recent years to the features of unstable nuclei and their collective multipole response. In the case of nuclei with some neutron excess, a strong fragmentation of strength has been observed in the isovector dipole response, mainly located at lower energy with respect to the GDR [2,3,4,5,6,7,8,9,10,11]. These low-lying excitations, which are referred in literature as Pygmy Dipole Resonance (PDR), have been the object of intense discussion [12,13,14,15,16,17,18,19,20,21,22,23], proving to be, likewise the GDR, an important probe of crucial information of the nuclear effective interaction, especially concerning its isovector component and the corresponding contribution to the Equation of State (EoS) [24,25,26], namely the symmetry energy.…”

Section: Introductionmentioning

confidence: 99%

The Symmetry Energy of the Nuclear EoS: A Study of Collective Motion and Low-Energy Reaction Dynamics in Semiclassical Approaches

2019

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In the framework of mean-field based transport approaches, we discuss recent results concerning collective motion and low-energy heavy ion reactions involving neutron-rich systems. We focus on aspects which are particularly sensitive to the isovector terms of the nuclear effective interaction and the corresponding symmetry energy. As far as collective excitations are concerned, we discuss the mixed nature of dipole oscillations in neutron-rich systems. On the other hand, for reactions close to the Coulomb barrier, we investigate the structure of pre-equilibrium collective dipole oscillations, focusing on their sensitivity to the symmetry energy behavior below normal density. Nucleon emission is also considered within the same context. The possible impact of other relevant terms of the nuclear effective interaction on these mechanisms is also examined. From this analysis we expect to put further constraints on the nuclear Equation of State, of crucial importance also in the astrophysical context.

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Total and partial photoneutron cross sections for Pb isotopes

Cited by 35 publications

References 30 publications

Photoneutron cross sections for neodymium isotopes: Toward a unified understanding of(γ,n)and(n,γ)reactions in the rare earth region

Photoneutron cross sections for neodymium isotopes: Toward a unified understanding of(γ,n)and(n,γ)reactions in the rare earth region

Pygmy and core polarization dipole modes in 206Pb: Connecting nuclear structure to stellar nucleosynthesis

The Symmetry Energy of the Nuclear EoS: A Study of Collective Motion and Low-Energy Reaction Dynamics in Semiclassical Approaches

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