Cross section measurement of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mmultiscripts><mml:mi mathvariant="normal">N</mml:mi><mml:mprescripts /><mml:none /><mml:mn>14</mml:mn></mml:mmultiscripts><mml:mo>(</mml:mo><mml:mi>p</mml:mi><mml:mo>,</mml:mo><mml:mi>γ</mml:mi><mml:mo>)</mml:mo><mml:mmultiscripts><mml:mi mathvariant="normal">O</mml:mi><mml:mprescripts /><mml:none /><mml:mn>15</mml:mn></mml:mmultiscripts></mml:mrow></mml:math>in the CNO cycle

Li, Q.; Görres, J.; deBoer, R. J.; Imbriani, G.; Best, A.; Kontos, A.; LeBlanc, P. J.; Uberseder, E.; Wiescher, M.

doi:10.1103/physrevc.93.055806

Cited by 34 publications

(47 citation statements)

References 37 publications

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“…A new result [124] has been published last year on the measurement of 14 N(p,γ) 15 O performed by using a 1 MV and a 4 MV accelerators at the University of Notre Dame. The cross of 14 N(p,γ) 15 O was measured over the proton energy range from 0.7 to 3.6 MeV for both the ground state and the 6.79 MeV transition.…”

Section: A New Study Of 14 N(pγ) 15 Omentioning

confidence: 99%

LUNA: Status and prospects

Broggini

Bemmerer

Caciolli

et al. 2018

Progress in Particle and Nuclear Physics

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The essential ingredients of nuclear astrophysics are the thermonuclear reactions which shape the life and death of stars and which are responsible for the synthesis of the chemical elements in the Universe. Deep underground in the Gran Sasso Laboratory the cross sections of the key reactions responsible for the hydrogen burning in stars have been measured with two accelerators of 50 and 400 kV voltage right down to the energies of astrophysical interest. As a matter of fact, the main advantage of the underground laboratory is the reduction of the background. Such a reduction has allowed, for the first time, to measure relevant cross sections at the Gamow energy. The qualifying features of underground nuclear astrophysics are exhaustively reviewed before discussing the current LUNA program which is mainly devoted to the study of the Big-Bang nucleosynthesis and of the synthesis of the light elements in AGB stars and classical novae. The main results obtained during the study of reactions relevant to the Sun are also reviewed and their influence on our understanding of the properties of the neutrino, of the Sun and of the Universe itself is discussed. Finally, the future of LUNA during the next decade is outlined. It will be mainly focused on the study of the nuclear burning stages after hydrogen burning: helium and carbon burning. All this will be accomplished thanks to a new 3.5 MV accelerator able to deliver high current beams of proton, helium and carbon which will start running under Gran Sasso in 2019. In particular, we will discuss the first phase of the scientific case of the 3.5 MV accelerator focused on the study of 12 C+ 12 C and of the two reactions which generate free neutrons inside stars: 13 C(α,n) 16 O and 22 Ne(α,n) 25 Mg. arXiv:1707.07952v4 [nucl-ex]

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Section: A New Study Of 14 N(pγ) 15 Omentioning

confidence: 99%

LUNA: Status and prospects

Broggini

Bemmerer

Caciolli

et al. 2018

Progress in Particle and Nuclear Physics

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“…While this demonstrates the significance of the scattering data, other uncertainties, like the sensitivity of the fit to the channel radius, background poles, experimental systematic uncertainties, and compatibility of the different capture data sets, are very significant and must be characterized before a new recommended value of the low energy S-factor can be given. To accomplish this, a detailed global analysis is in progress, which also includes newly measured capture data that cover the higher energy range [35]. These new capture data have been measured with the aim of improving on those of Ref.…”

Section: Discussionmentioning

confidence: 99%

Low energy scattering cross section ratios ofN14(p,p)N14

et al. 2015

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Background The slowest reaction in the first CNO cycle is 14 N(p, γ) 15 O, therefore its rate determines the overall energy production efficiency of the entire cycle. The cross section presents several strong resonance contributions, especially for the ground state transition. Some of the properties of the corresponding levels in the 15 O compound nucleus remain uncertain, which affects the uncertainty in extrapolating the capture cross section to the low energy range of astrophysical interest. Purpose The14 N(p, γ) 15 O cross section can be described using phenomenological R-matrix. Over the energy range of interest, only the proton and γ-ray channels are open. Since resonance capture makes significant contributions to the 14 N(p, γ) 15 O cross section, resonant proton scattering data can be used to provide additional constraints on the R-matrix fit of the capture data.Methods A 4 MV KN Van de Graaff accelerator was used to bombard protons onto a windowless gas target containing enriched 14 N gas over the proton energy range from Ep = 1.0 to 3.0 MeV. Scattered protons were detected at θ lab = 90, 120, 135, 150, and 160• using ruggedized silicon detectors. In addition, a 10 MV FN Tandem Van de Graaff accelerator was used to accelerate protons onto a solid Adenine target, of natural isotopic abundance, evaporated onto a thin self-supporting carbon backing, over the energy range from Ep = 1.8 to 4.0 MeV. Scattered protons were detected at 28 angles between θ lab = 30.4 and 167.7• using silicon photodiode detectors.Results Relative cross sections were extracted from both measurements. While the relative cross sections do not provide as much constraint as absolute measurements, they greatly reduce the dependence of the data on otherwise significant systematic uncertainties, which are more difficult to quantify. The data are fit simultaneously using an R-matrix analysis and level energies and proton widths are extracted. Even with relative measurements, the statistics and large angular coverage of the measurements result in more confident values for the energies and proton widths of several levels in particular the broad resonance at Ecm = 2.21 MeV, which corresponds to the 3/2 + level at Ex = 9.51 MeV in 15 O. In particular the s and d wave angular momentum channels are separated. ConclusionThe relative cross sections provide a consistent set of data that can be used to better constrain a full multichannel R-matrix extrapolation of the capture data. It has been demonstrated how the scattering data reduce the uncertainty through a preliminary Monte Carlo uncertainty analysis, but several other issues remain that make large contributions to the uncertainty, which must be addressed by further capture and lifetime measurements.

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“…Another recent measurements has been performed at the Notre Dame University [33] at higher energies obtaining an extrapolated value higher than the one reported by LUNA. In this context a new measurement is requested in a wide energy range and it will be done as first measurement of the future LUNA MV accelerator, which will cover an energy range from 3 MeV down to 200 keV with an unique set of data, leading to precise extrapolation.…”

Section: Epj Web Of Conferencesmentioning

confidence: 92%

“…The first reaction will be the 14 N(p,γ) 15 O. The solar composition problem has been already addressed above and recently a new measurement has been performed at high energy founding discrepancies with the LUNA data [33]. With the new LUNA MV it will be possibile to cover with an unique set of data a wide energy range from 2 MeV down to the LUNA2 energies, allowing to reduce the systematics down to the goal of 5%.…”

Section: Big Bang Nucleosynthesismentioning

confidence: 99%

Nuclear Astrophysics in underground laboratories: the LUNA experiment

Simpson¹,

Simenel²,

Cook³

et al. 2017

EPJ Web Conf.

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Abstract. One of the main ingredients of nuclear astrophysics is the knowledge of the thermonuclear reactions responsible for powering the stellar engine and for the synthesis of the chemical elements. At astrophysical energies the cross section of nuclear processes is extremely reduced by the effect of the Coulomb barrier. The low value of cross sections prevents their measurement at stellar energies on Earth surface and often extrapolations are needed. The Laboratory for Underground Nuclear Astrophysics (LUNA) is placed under the Gran Sasso mountain and thanks to the cosmic-ray background reduction provided by its position can investigate cross sections at energies close to the Gamow peak in stellar scenarios. Many crucial reactions involved in hydrogen burning has been measured directly at astrophysical energies with both the LUNA-50kV and the LUNA-400kV accelerators, and this intense work will continue with the installation of a MV machine able to explore helium and carbon burnings. Based on this progress, currently there are efforts in several countries to construct new underground accelerators. In this talk, the typical techniques adopted in underground nuclear astrophysics will be described and the most relevant results achieved by LUNA will be reviewed. The exciting science that can be probed with the new facilities will be highlighted.

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Cross section measurement ofN14(p,γ)O15in the CNO cycle

Cited by 34 publications

References 37 publications

LUNA: Status and prospects

LUNA: Status and prospects

Low energy scattering cross section ratios ofN14(p,p)N14

Nuclear Astrophysics in underground laboratories: the LUNA experiment

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