Neutron capture rates near<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>A</mml:mi><mml:mo>=</mml:mo><mml:mn>130</mml:mn></mml:mrow></mml:math>that effect a global change to the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>r</mml:mi></mml:mrow></mml:math>-process abundance distribution

Surman, Rebecca; Beun, J.A.; McLaughlin, G. C.; Hix, W. R.

doi:10.1103/physrevc.79.045809

Cited by 71 publications

(56 citation statements)

References 27 publications

(25 reference statements)

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“…The r-process is responsible for the production of half of the nuclides heavier than iron. In a recent study [5], variations of the * zss76@buaa.edu.cn † smithms@ornl.gov 130 Sn(n, γ ) capture rate were surprisingly shown to have a global impact on r-process simulations, changing final abundance calculations of nuclei over hundreds of mass units.…”

mentioning

confidence: 99%

Structures of exotic131,133Sn isotopes and effect onr-process nucleosynthesis

et al. 2012

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Background: Four strong single-particle bound levels with strikingly similar level spacings have recently been measured in 131 Sn and 133 Sn. This similarity has not yet been addressed by a theoretical nuclear structure model. Information on these single-particle bound levels, as well as on resonant levels above the neutron capture threshold, is also needed to determine neutron capture cross sections-and corresponding capture reaction rates-on 130,132 Sn. The 130 Sn(n, γ ) rate was shown in a recent sensitivity study to significantly impact the synthesis of heavy elements in the r-process in supernovae.Purpose: Understand the structure of bound and resonant levels in 131,133 Sn, and determine if the densities of unbound resonant levels are sufficiently high to warrant statistical model treatments of neutron capture on 130,132 Sn. Method: Single-particle bound and resonant levels for 131,133 Sn are self-consistently calculated by the analytical continuation of the coupling constant (ACCC) method based on a relativistic mean field (RMF) theory with BCS approximation.Results: We obtain four strong single-particle bound levels in both 131,133 Sn with an ordering that agrees with experiments and spacings that, while differing from experiment, are consistent between the Sn isotopes. We also find at most one single-particle level in the effective energy range for neutron captures in the r-process.Conclusions: Our RMF + ACCC + BCS model successfully reproduces observed single-particle bound levels in 131,133 Sn and self-consistently predicts single-particle resonant levels with densities too low for widely used traditional statistical model treatments of neutron capture cross sections on 130,132 Sn employing Fermi gas level density formulations.

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confidence: 99%

Structures of exotic131,133Sn isotopes and effect onr-process nucleosynthesis

et al. 2012

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“…The states above the N=82 shell gap in 131 Sn have large spectroscopic factors consistent with single-neutron configurations with limited fragmentation. Recent work [1] has shown how uncertainties in neutron capture on 130 Sn could have significant impacts on r-process abundances.…”

Section: Previous Studies Near 132 Snmentioning

confidence: 99%

“…The r-process path of nucleosynthesis goes through many neutron-rich nuclei with waiting points near the N=50 and 82 closed shells. Recent calculations [1] of the sensitivity of r-process abundances to neutron-capture crosssections during freeze-out have highlighted the importance of certain (n,Ȗ) cross sections to understanding observed abundances. The spectroscopic strengths of single-neutron excitations are important ingredients in calculating the direct component of neutron capture.…”

Section: Introductionmentioning

confidence: 99%

Single-neutron levels near the N=82 shell closure

Manning¹,

Cizewski²,

Kozub³

et al. 2013

AIP Conference Proceedings

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The (d,p) reaction was measured with the radioactive ion beams of 126 Sn and 128 Sn in inverse kinematics at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory, utilizing the SuperORRUBA silicon detector array. Angular distributions of reaction protons were measured for several states in 127 Sn and 129 Sn to determine angular momentum transfers and deduce spectroscopic factors. Such information is critical for calculating direct (n,Ȗ) cross sections for the r-process as well as for constraining shell model parameters in the A §130 region. Combined with previous experiments on 130 Sn and 132 Sn, these results will provide a complete set of (d,p) reaction data on even tin isotopes between stable 124 Sn and doubly-magic 132 Sn.

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“…32,33 Crucial to the total neutron capture rate on 130 Sn is direct capture through bound states in 131 Sn. Particularly important to the direct-capture cross section is the location of states with significant spectroscopic overlap with a single = 1 neutron coupled to 130 Sn, which correspond to the 3p 3/2 and 3p 1/2 shell-model states above the N = 82 shell closure.…”

Section: B Neutron Transfer Reactions To Inform Neutron-capture Crosmentioning

confidence: 99%

Advances in instrumentation for nuclear astrophysics

Pain

2014

AIP Advances

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The study of the nuclear physics properties which govern energy generation and nucleosynthesis in the astrophysical phenomena we observe in the universe is crucial to understanding how these objects behave and how the chemical history of the universe evolved to its present state. The low cross sections and short nuclear lifetimes involved in many of these reactions make their experimental determination challenging, requiring developments in beams and instrumentation. A selection of developments in nuclear astrophysics instrumentation is discussed, using as examples projects involving the nuclear astrophysics group at Oak Ridge National Laboratory. These developments will be key to the instrumentation necessary to fully exploit nuclear astrophysics opportunities at the Facility for Rare Isotope Beams which is currently under construction.

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Neutron capture rates nearA=130that effect a global change to ther-process abundance distribution

Cited by 71 publications

References 27 publications

Structures of exotic131,133Sn isotopes and effect onr-process nucleosynthesis

Structures of exotic131,133Sn isotopes and effect onr-process nucleosynthesis

Single-neutron levels near the N=82 shell closure

Advances in instrumentation for nuclear astrophysics

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