2H + reactions from 1.96 to 6.20 MeV

Schulte, Robert; Cosack, M.; Obst, A. W.; Weil, J.L.

doi:10.1016/0375-9474(72)90093-0

Cited by 64 publications

(46 citation statements)

References 12 publications

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“…15 represents the ratio of theoretical cross sections compared with the data sets to be discussed below. Confidence in this theoretical shape is reinforced by fact that the most recent directly measured [16] and higher energy [40] experimental data sets follow precisely (except for a few data points) this curve. This can hardly be accidental: even though the model, because of limitations on angular momentum, underestimates the high energy absolute cross-sections, the ratio is well reproduced, suggesting that it is indeed independent of the nuclear matrix elements.…”

Section: The Ma Et Al Datamentioning

confidence: 65%

New reaction rates for improved primordialD/Hcalculation and the cosmic evolution of deuterium

et al. 2015

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Primordial or big bang nucleosynthesis (BBN) is one of the three historical strong evidences for the big bang model. Standard BBN is now a parameter free theory, since the baryonic density of the Universe has been deduced with an unprecedented precision from observations of the anisotropies of the cosmic microwave background (CMB) radiation. There is a good agreement between the primordial abundances of 4 He, D, 3 He and 7 Li deduced from observations and from primordial nucleosynthesis calculations. However, the 7 Li calculated abundance is significantly higher than the one deduced from spectroscopic observations and remains an open problem. In addition, recent deuterium observations have drastically reduced the uncertainty on D/H, to reach a value of 1.6%. It needs to be matched by BBN predictions whose precision is now limited by thermonuclear reaction rate uncertainties. This is especially important as many attempts to reconcile Li observations with models lead to an increased D prediction. Here, we re-evaluates the d(p,γ) 3 He, d(d,n) 3 He and d (d,p) 3 H reaction rates that govern deuterium destruction, incorporating new experimental data and carefully accounting for systematic uncertainties. Contrary to previous evaluations, we use theoretical ab initio models for the energy dependence of the S-factors. As a result, these rates increase at BBN temperatures, leading to a reduced value of D/H = (2.45±0.10) × 10 −5 (2σ), in agreement with observations.

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Section: The Ma Et Al Datamentioning

confidence: 65%

New reaction rates for improved primordialD/Hcalculation and the cosmic evolution of deuterium

et al. 2015

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“…Thus to calculate reaction rates accurately, we must include data at energies higher than those of the present work, although data at these energies contribute relatively little to the integral at the relevant temperatures. For this purpose and to make a fair judgment of how the new data compare to the NACRE compilation, we have used the same data at high energies as those used in NACRE compilation, the data of Schulte et al [37]. We have included this data up to E c.m.…”

Section: Results Implications and Conclusionmentioning

confidence: 99%

“…III E. The coefficients are normalized to the P0 coefficients. [37] The statistical uncertainties of Ref. [37] were multiplied by 5 in the figure and the fit.…”

Section: Results Implications and Conclusionmentioning

confidence: 99%

Precision measurements ofH2(d,p)
Leonard
¹
,
Karwowski
²
,
Brune
³

et al. 2006
Phys. Rev. C

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Recent Wilkinson Microwave Anisotropy Probe (WMAP) measurements have determined the baryon density of the Universe Ω b with a precision of about 4%. With Ω b tightly constrained, comparisons of Big Bang Nucleosynthesis (BBN) abundance predictions to primordial abundance observations can be made and used to test BBN models and/or to further constrain abundances of isotopes with weak observational limits. To push the limits and improve constraints on BBN models, uncertainties in key nuclear reaction rates must be minimized. To this end, we made new precise measurements of theHe total cross sections at lab energies from 110 keV to 650 keV. A complete fit was performed in energy and angle to both angular distribution and normalization data for both reactions simultaneously. By including parameters for experimental variables in the fit, error correlations between detectors, reactions, and reaction energies were accurately tabulated by computational methods. With uncertainties around 2% ± 1% scale error, these new measurements significantly improve on the existing data set. At relevant temperatures, using the data of the present work, both reaction rates are found to be about 7% higher than those in the widely used Nuclear Astrophysics Compilation of Reaction Rates (NACRE). These data will thus lead not only to reduced uncertainties, but also to modifications in the BBN abundance predictions.

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“…The astrophysical factor S(E) for the nuclear reaction (1) after the background subtraction (solid black circles), where the effective Gamow peak energy is used as Ec.m.. "Conventional" experiments [1][2][3][4][5][6][7] are included for comparison.…”

Section: Figmentioning

confidence: 99%

“…The role of low-energy nuclear physics is crucial in both astrophysics, playing a key role in the determination of primordial abundances in Big Bang nucleosynthesis (BBN) models, and applied (plasma) physics, as it lies in the energy region of interest for the operation and design of future fusion power plants. Direct and indirect measurements of the cross-sections of these reactions have been performed * lattuadad@lns.infn.it over the years [1][2][3][4][5][6][7][8][9][10], some suggesting that a screening potential due to electrons can lower the Coulomb barrier between the projectile and the target nuclei at very low energies [11,12], resulting in an increase of the cross-section when compared with that of the same interaction with bare nuclei and with the ones occurring in astrophysical plasmas [1,6,13,14].…”

Section: Introductionmentioning

confidence: 99%

Model-independent determination of the astrophysicalSfactor in laser-induced fusion plasmas

et al. 2016

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In this work, we present a new and general method for measuring the astrophysical S-factor of nuclear reactions in laser-induced plasmas and we apply it to 2 H(d,n) 3 He. The experiment was performed with the Texas Petawatt laser, which delivered 150-270 fs pulses of energy ranging from 90 to 180 J to D2 or CD4 molecular clusters. After removing the background noise, we used the measured time-of-flight data of energetic deuterium ions to obtain their energy distribution. We derive the S-factor using the measured energy distribution of the ions, the measured volume of the fusion plasma and the measured fusion yields. This method is model-independent in the sense that no assumption on the state of the system is required, but it requires an accurate measurement of the ion energy distribution especially at high energies and of the relevant fusion yields. In the 2 H(d,n) 3 He and 3 He(d,p) 4 He cases discussed here, it is very important to apply the background subtraction for the energetic ions and to measure the fusion yields with high precision. While the available data on both ion distribution and fusion yields allow us to determine with good precision the S-factor in the d+d case (lower Gamow energies), for the d+ 3 He case the data are not precise enough to obtain the S-factor using this method. Our results agree with other experiments within the experimental error, even though smaller values of the S-factor were obtained. This might be due to the plasma environment differing from the beam target conditions in a conventional accelerator experiment.

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2H + reactions from 1.96 to 6.20 MeV

Cited by 64 publications

References 12 publications

New reaction rates for improved primordialD/Hcalculation and the cosmic evolution of deuterium

New reaction rates for improved primordialD/Hcalculation and the cosmic evolution of deuterium

Precision measurements ofH2(d,p)
Leonard
¹
,
Karwowski
²
,
Brune
³

et al. 2006
Phys. Rev. C

Model-independent determination of the astrophysicalSfactor in laser-induced fusion plasmas

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2H + reactions from 1.96 to 6.20 MeV

Cited by 64 publications

References 12 publications

New reaction rates for improved primordialD/Hcalculation and the cosmic evolution of deuterium

New reaction rates for improved primordialD/Hcalculation and the cosmic evolution of deuterium

Precision measurements ofH2(d,p)Leonard1, Karwowski2, Brune3 et al. 2006Phys. Rev. C

Model-independent determination of the astrophysicalSfactor in laser-induced fusion plasmas

Contact Info

Product

Resources

About

Precision measurements ofH2(d,p)
Leonard
¹
,
Karwowski
²
,
Brune
³

et al. 2006
Phys. Rev. C