Determination of the excitation function for the reaction T(d, n) He4

Davidenko, V. A.; Pogrebov, I.S.; Saukov, A.I.

doi:10.1007/bf01489638

Cited by 5 publications

(3 citation statements)

References 7 publications

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“…Hofstee et al (a conference proceeding) [109], also quoted in NACRE-II is not considered either (two data points with large (±5% ± 2%) uncertainty). Davidenko et al [110] quote a 20% uncertainty on d(d,n) 3 He. Data from Ganeev et al [46] can be obtained from [108].…”

Section: Miscellaneousmentioning

confidence: 99%

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: Miscellaneousmentioning

confidence: 99%

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

et al. 2015

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“…The t(d, n) 4 He reaction is a main production route to 4 He. We will consider the data sets of Allan (1951) [87], Argo (1952) [88], Arnold (1954) [71], Bame Jr. (1957) [89], Brown (1987) [90], [91], Davidenko (1957) [92], [93] and Research Group (1985) [73]. We This assumption is good up to energies of E ∼ 240 keV, thus we exclude any Conner data that lie beyond this energy.…”

Section: T(d N) 4 Hementioning

confidence: 99%

Primordial nucleosynthesis for the new cosmology: Determining uncertainties and examining concordance

2004

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Big bang nucleosynthesis ͑BBN͒ and the cosmic microwave background ͑CMB͒ have a long history together in the standard cosmology. BBN accurately predicts the primordial light element abundances of deuterium, helium and lithium. The general concordance between the predicted and observed light element abundances provides a direct probe of the universal baryon density. Recent CMB anisotropy measurements, particularly the observations performed by the WMAP satellite, examine this concordance by independently measuring the cosmic baryon density. Key to this test of concordance is a quantitative understanding of the uncertainties in the BBN light element abundance predictions. These uncertainties are dominated by systematic errors in nuclear cross sections, however for helium-4 they are dominated by the uncertainties in the neutron lifetime and Newton's G. We critically analyze the cross section data, producing representations that describe this data and its uncertainties, taking into account the correlations among data, and explicitly treating the systematic errors between data sets. The procedure transforming these representations into thermal rates and errors is discussed. Using these updated nuclear inputs, we compute the new BBN abundance predictions, and quantitatively examine their concordance with observations. Depending on what deuterium observations are adopted, one gets the following constraints on the baryon density: ⍀ B h 2 ϭ0.0229Ϯ0.0013 or ⍀ B h 2 ϭ0.0216 Ϫ0.0021 ϩ0.0020 at 68% confidence, fixing N ,e f f ϭ3.0. If we instead adopt the WMAP baryon density, we find the following deuterium-based constraints on the effective number of neutrinos during BBN: N ,e f f ϭ2.78 Ϫ0.76 ϩ0.87 or N ,e f f ϭ3.65 Ϫ1.30 ϩ1.46 at 68% confidence. Concerns over systematics in helium and lithium observations limit the confidence constraints based on this data provide. BBN theory uncertainties are dominated by the following nuclear reactions: d(d,n) 3 He, d(d,p)t, d(p,␥) 3 He, 3 He(␣,␥) 7 Be and 3 He(d,p) 4 He. With new nuclear cross section data, light element abundance observations and the ever increasing resolution of the CMB anisotropy, tighter constraints can be placed on nuclear and particle astrophysics.

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“…Experimental data on the cross sections are most fully presented in [13][14][15][16]. In view of the discrepancies in the experimental values of cross sections found in a number of papers [17][18][19], we carried out an additional monitoring of experimental cross section analysis with use of modern approximations that make it possible to obtain convenient analytical curves for different cross sections and also for rates s á ñ v of the reactions. In this case, for our calculations we use data obtained through conducting the known double-period method approximation [20,21].…”

Section: Thermonuclear Reactions Ratesmentioning

confidence: 99%

Study of a dense hot plasma’s burning in Z-pinch devices with inertial-magnetic confinement

Seksembayev¹,

Kukulin²,

Sakhiyev³

2018

Phys. Scr.

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The burning kinetics of dense hot plasma of composition D+D, D+T, D+ 3 He in devices with inertial-magnetic confinement concept is considered. Calculations of the burning kinetics of main fusion reactions in plasma with use of modern refined data on reaction rates at the appropriate temperatures and several types of energy loss for radiation have been made. An analysis of the energy yield is performed taking into account the change in plasma temperature and the heating of burning area in equilibrium plasma, which is described by Maxwell distribution, as well as the analysis of energy exchange between two adjacent burning volumes with different temperatures. Based on all the data found, estimates of the burning properties of plasma in thermonuclear devices with inertial-magnetic confinement of plasma have been made.

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Determination of the excitation function for the reaction T(d, n) He4

Cited by 5 publications

References 7 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

Primordial nucleosynthesis for the new cosmology: Determining uncertainties and examining concordance

Study of a dense hot plasma’s burning in Z-pinch devices with inertial-magnetic confinement

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