Low-Energy<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi mathvariant="normal">He</mml:mi></mml:mrow><mml:mprescripts /><mml:mrow /><mml:mrow><mml:mn>3</mml:mn></mml:mrow><mml:mrow /><mml:mrow /></mml:mmultiscripts></mml:mrow><mml:mo>(</mml:mo><mml:mi>α</mml:mi><mml:mo>,</mml:mo><mml:mi> </mml:mi><mml:mi>γ</mml:mi><mml:mo>)</mml:mo><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi mathvariant="normal">Be</mml:mi></mml:mrow><mml:mprescrip

Osborne, J. L.; Barnes, C. A.; Kavanagh, R. W.; Kremer, Richard M.; Mathews, G. J.; Zyskind, J.L.; Parker, P. D.; Howard, A. J.

doi:10.1103/physrevlett.48.1664

Cited by 77 publications

(149 citation statements)

References 8 publications

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“…While the energy dependence of these models is in good agreement with the energy dependence of the measured cross sections, it would be useful to carry out a theoretical study of how robust this energy dependence is for a wider range of models. Osborne et al (1982Osborne et al ( ,1984 0.63 Ϯ 0.04 Robertson et al (1983) 0.56 Ϯ 0.03 Volk et al (1983) Weighted mean=0.579 Ϯ 0.024 a As extrapolated using the direct-capture model of Tombrello and Parker (1963). b As renormalized by Hilgemeier et al (1988).…”

Section: Hydrogen Burning In the Pp Chain And Cn Cyclementioning

confidence: 99%

Synthesis of the elements in stars: forty years of progress

et al. 1997

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Forty years ago Burbidge, Burbidge, Fowler, and Hoyle combined what we would now call fragmentary evidence from nuclear physics, stellar evolution and the abundances of elements and isotopes in the solar system as well as a few stars into a synthesis of remarkable ingenuity. Their review provided a foundation for forty years of research in all of the aspects of low energy nuclear experiments and theory, stellar modeling over a wide range of mass and composition, and abundance studies of many hundreds of stars, many of which have shown distinct evidence of the processes suggested by B 2 FH. In this review we summarize progress in each of these fields with emphasis on the most recent developments. [S0034-6861(97)

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Section: Hydrogen Burning In the Pp Chain And Cn Cyclementioning

confidence: 99%

Synthesis of the elements in stars: forty years of progress

et al. 1997

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“…The cross section can be measured by detecting either the induced 7 Be activity (activation method) or the prompt γ-rays from the reaction (prompt-γ method). Previous activation studies [15,16,17,18] cover the energy range E = 420-2000 keV. Prompt γ-ray measurements [15,19,20,21,22,23,24] cover E = 107-2500 keV, although with limited precision at low energies.…”

mentioning

confidence: 99%

Activation Measurement of theHe3(α,γ)Be7Cross Section at Low Energy

Bemmerer¹,

Confortola²,

Costantini³

et al. 2006

Phys. Rev. Lett.

149

208

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The nuclear physics input from the 3 He(α, γ) 7 Be cross section is a major uncertainty in the fluxes of 7 Be and 8 B neutrinos from the Sun predicted by solar models and in the 7 Li abundance obtained in big-bang nucleosynthesis calculations. The present work reports on a new precision experiment using the activation technique at energies directly relevant to big-bang nucleosynthesis. Previously such low energies had been reached experimentally only by the prompt-γ technique and with inferior precision. Using a windowless gas target, high beam intensity and low background γ-counting facilities, the 3 He(α, γ) 7 Be cross section has been determined at 127, 148 and 169 keV center-of-mass energy with a total uncertainty of 4 %. The sources of systematic uncertainty are discussed in detail. The present data can be used in big-bang nucleosynthesis calculations and to constrain the extrapolation of the 3 He(α, γ) 7 Be astrophysical S-factor to solar energies. The 3 He(α, γ) 7 Be reaction is a critical link in the 7 Be and 8 B branches of the proton-proton (p-p) chain of solar hydrogen burning [1]. At low energies its cross section σ(E) (E denotes the center of mass energy, E α the 4 He beam energy in the laboratory system) can be parameterized by the astrophysical S-factor S(E) defined as. The 9.4 % uncertainty [3] in the Sfactor extrapolation to the solar Gamow energy (23 keV) contributes 8 % to the uncertainty in the predicted fluxes of solar neutrinos from the decays of 7 Be and 8 B [4]. The interior of the Sun, in turn, can be studied [4,5] by comparing this prediction with the data from neutrino detectors [6,7], which determine the 8 B neutrino flux with a total uncertainty as low as 3.5 % [7].Furthermore, the production of 7 Li in big-bang nucleosynthesis (BBN) is highly sensitive to the 3 He(α, γ) 7 Be cross section in the energy range E ≈ 160-380 keV [8], with an adopted uncertainty of 8 % [9]. Based on the baryon-to-photon ratio from observed anisotropies in the cosmic microwave background [10], network calculations predict primordial 7 Li abundances [11] that are significantly higher than observations [12,13]. A lower 3 He(α,γ)7 Be cross section at relevant energies may explain part of this discrepancy. The3 He(α,γ) 7 Be (Q-value: 1.586 MeV) reaction leads to the emission of prompt γ-rays, and the final 7 Be nucleus decays with a half-life of 53.22 ± 0.06 days, emitting a 478 keV γ-ray in 10.44 ± 0.04 % of the cases [14]. The cross section can be measured by detecting either the induced 7 Be activity (activation method) or the prompt γ-rays from the reaction (prompt-γ method). Previous activation studies [15,16,17,18] cover the energy range E = 420-2000 keV. Prompt γ-ray measurements [15,19,20,21,22,23,24] cover E = 107-2500 keV, although with limited precision at low energies.The global shape of the S-factor curve is well reproduced by theoretical calculations [25,26]. However, the slope has been questioned [26] for E ≤ 300 keV, where there are no high-precision data. Furthermore, a global analysis [3] ind...

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“…This experiment was carried out at a single energy point only and may have had an additional systematic error. The work of Osborne et al [14] again results in a somewhat higher S(0). Although Table 3.…”

Section: Comparison Of the Results Of Various Activation Experimentsmentioning

confidence: 69%

“…Although Table 3. Extrapolated S(0) values from different activation experiments renormalizing the R matrix curve of Descouvemont et al [24] experiment S(0) [keV b] Osborne et al [14] 0.60 ± 0.04 Robertson et al [17] 0.67 ± 0.04 Nara Singh et al [7] 0.551 ± 0.022 LUNA activation [19,20,21] The results of all activation experiments on the 3 He(α, γ) 7 Be reaction. The R-matrix calculation of Descouvemont et al [24] normalized to the LUNA and Nara Singh et al data is also shown.…”

Section: Comparison Of the Results Of Various Activation Experimentsmentioning

confidence: 99%

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Comparison of the LUNA³He(α, γ)⁷Be activation results with earlier measurements and model calculations

Gyürky

Bemmerer

Confortola

et al. 2007

J. Phys. G: Nucl. Part. Phys.

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Abstract. Recently, the LUNA collaboration has carried out a high precision measurement on the 3 He(α, γ) 7 Be reaction cross section with both activation and online γ-detection methods at unprecedented low energies. In this paper the results obtained with the activation method are summarized. The results are compared with previous activation experiments and the zero energy extrapolated astrophysical S factor is determined using different theoretical models.

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Low-EnergyHe3(α, γ)Be

Cited by 77 publications

References 8 publications

Synthesis of the elements in stars: forty years of progress

Synthesis of the elements in stars: forty years of progress

Activation Measurement of theHe3(α,γ)Be7Cross Section at Low Energy

Comparison of the LUNA³He(α, γ)⁷Be activation results with earlier measurements and model calculations

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Low-EnergyHe3(α, γ)Be

Cited by 77 publications

References 8 publications

Synthesis of the elements in stars: forty years of progress

Synthesis of the elements in stars: forty years of progress

Activation Measurement of theHe3(α,γ)Be7Cross Section at Low Energy

Comparison of the LUNA3He(α, γ)7Be activation results with earlier measurements and model calculations

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Product

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Comparison of the LUNA³He(α, γ)⁷Be activation results with earlier measurements and model calculations