Low-energy cross sections for the 6Li(p, 3He)4He reaction

Kwon, Ji-Won; Kim, J.C.; Sung, B.N.

doi:10.1016/0375-9474(89)90535-6

Cited by 20 publications

(10 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although the absolute cross section was measured at very low energy (Engstler et al 1988;Kwon et al 1989;Engstler et al 1992), experimental data below 100 keV could not be used to determine the bare nucleus S(E) dependence for a center-of-mass energy approaching zero, since it is affected by the electron screening. Thus a polynomial expansion S b = a+bE+cE 2 +dE 3 was used to fit the data for both atomic and molecular targets above 100 keV in order to extrapolate the behavior of the bare nucleus S b (E) factor to the lower energy region.…”

Section: Experimental Results On the 6 Li(pα) 3 Hementioning

confidence: 99%

“…The direct 6 Li(p,α) 3 He reaction was performed using a proton beam and a 6 Li solid target, as well as a 6 Li beam and a H 2 gas target (Engstler et al 1988;Kwon et al 1989;Engstler et al 1992). Although the absolute cross section was measured at very low energy (Engstler et al 1988;Kwon et al 1989;Engstler et al 1992), experimental data below 100 keV could not be used to determine the bare nucleus S(E) dependence for a center-of-mass energy approaching zero, since it is affected by the electron screening.…”

Section: Experimental Results On the 6 Li(pα) 3 Hementioning

confidence: 99%

See 1 more Smart Citation

Trojan Horse estimate of bare nucleus astrophysical S(E)-factor for the $\mathsf{^{6}}$Li(p,α)$^{\mathsf{3}}$He reaction and its astrophysical implications

Pizzone

Туміно

Degl’Innocenti

et al. 2005

A&A

View full text Add to dashboard Cite

Abstract.The 6 Li(p, α) 3 He bare nucleus cross-section at astrophysical energies has been indirectly measured in the framework of the Trojan-Horse Method, finding an agreement within the experimental errors with the results of data extrapolations from direct methods. This result is thus an independent check of the extrapolation method used until now. The method of measure is recalled and the results are shown with particular attention to the bare cross section value at the Gamow energy. The quoted agreement between direct and indirect methods is discussed in the context of the surface lithium abundances in stars. It is shown that the problem of stellar lithium abundances is not at the nuclear physics level but it is an astrophysics problem that requires improvements in our knowledge of the mixing mechanisms, the reduction of the uncertainties on the other (nonnuclear) physical inputs, and more precise observational data.

show abstract

Section: Experimental Results On the 6 Li(pα) 3 Hementioning

confidence: 99%

Section: Experimental Results On the 6 Li(pα) 3 Hementioning

confidence: 99%

Trojan Horse estimate of bare nucleus astrophysical S(E)-factor for the $\mathsf{^{6}}$Li(p,α)$^{\mathsf{3}}$He reaction and its astrophysical implications

Pizzone

Туміно

Degl’Innocenti

et al. 2005

A&A

View full text Add to dashboard Cite

show abstract

“…Clearly, a thorough understanding of screening effects requires additional efforts in theory as well as in experiment, where improved lowenergy data for other fusion reactions are needed. The published total cross sections for the fusion reactions 6Li(p, ~)3He [6][7][8][9][10][11][12][13], 6Li(d, 004He [10,[14][15][16][17][18] and 7Li(p, c04He [8,9,19,20], with respective Q values of 4.02, 22.37, and 17. 35 MeV, are shown in Fig.…”

Section: (E) = As (E)/ab (E) ~-Exp (~Z Q U~/e)mentioning

confidence: 99%

Isotopic dependence of electron screening in fusion reactions

Engstler

Raimann

Angulo

et al. 1992

Z. Physik A - Hadrons and Nuclei

138

176

View full text Add to dashboard Cite

The fusion reactions 6Li (p, cQ3He, 6Li(d,~)4He, and 7Li(p, c~)4He have been studied over the c.m. energy range E = 10 to 1450 keV. Each reaction involved the use of hydrogen projectiles and LiF solid targets as well as Li projectiles and hydrogen molecular gas targets. In all cases the effects of electron screening on the low-energy fusion cross sections (exponential enhancement) have been observed; the effects are somewhat stronger in the case of atomic p or d projectiles compared to the case of molecular H 2 or D2 gas targets. If isotopic effects on electron screening are negligible, all three reactions should exhibit the same enhancements for each set of experimental techniques. The measurements confirmed this expectation to a large extent.

show abstract

“…The total error in S(0) accounts for the statistical error on the TH experimental points (∼7% an average), and on the direct data as well (∼7% an average) and a ∼3% uncertainty due to the normalization procedure. The electron screening potential U e was extracted by fitting the low-energy (<70 keV) direct data of Engstler et al (1992) and Cruz et al (2005) using the formula Kwon et al (1989), and Cruz et al (2008). The previous TH measurements discussed in Tumino et al (2003) are also shown as black points.…”

Section: The Trojan Horse Methodsmentioning

confidence: 99%

“…The 6 Li(p, α) 3 He reaction rate has been extracted here by integrating the TH S b (E) (as in Equation (4)) over the explored energy range corresponding to temperatures 0.01 T 9 2. In the NACRE compilation, the low-energy part of the S(E) factor is described via the extrapolation made by Kwon et al (1989). A more recent evaluation of the 6 Li(p, α) 3 He reaction rate is provided via the library JINA REACLIB (Cyburt et al 2010) which also refers to the previous TH investigation of Pizzone et al (2005).…”

Section: The Trojan Horse Methodsmentioning

confidence: 99%

AN UPDATED⁶Li(p, α)³He REACTION RATE AT ASTROPHYSICAL ENERGIES WITH THE TROJAN HORSE METHOD

Lamia

Spitaleri

Pizzone

et al. 2013

ApJ

View full text Add to dashboard Cite

The lithium problem influencing primordial and stellar nucleosynthesis is one of the most interesting unsolved issues in astrophysics. 6 Li is the most fragile of lithium's stable isotopes and is largely destroyed in most stars during the pre-main-sequence (PMS) phase. For these stars, the convective envelope easily reaches, at least at its bottom, the relatively low 6 Li ignition temperature. Thus, gaining an understanding of 6 Li depletion also gives hints about the extent of convective regions. For this reason, charged-particle-induced reactions in lithium have been the subject of several studies. Low-energy extrapolations of these studies provide information about both the zero-energy astrophysical S(E) factor and the electron screening potential, U e . Thanks to recent direct measurements, new estimates of the 6 Li(p, α) 3 He bare-nucleus S(E) factor and the corresponding U e value have been obtained by applying the Trojan Horse method to the 2 H( 6 Li, α 3 He)n reaction in quasi-free kinematics. The calculated reaction rate covers the temperature window 0.01 to 2T 9 and its impact on the surface lithium depletion in PMS models with different masses and metallicities has been evaluated in detail by adopting an updated version of the FRANEC evolutionary code.

show abstract

Low-energy cross sections for the 6Li(p, 3He)4He reaction

Cited by 20 publications

References 20 publications

Trojan Horse estimate of bare nucleus astrophysical S(E)-factor for the $\mathsf{^{6}}$Li(p,α)$^{\mathsf{3}}$He reaction and its astrophysical implications

Trojan Horse estimate of bare nucleus astrophysical S(E)-factor for the $\mathsf{^{6}}$Li(p,α)$^{\mathsf{3}}$He reaction and its astrophysical implications

Isotopic dependence of electron screening in fusion reactions

AN UPDATED⁶Li(p, α)³He REACTION RATE AT ASTROPHYSICAL ENERGIES WITH THE TROJAN HORSE METHOD

Contact Info

Product

Resources

About

Low-energy cross sections for the 6Li(p, 3He)4He reaction

Cited by 20 publications

References 20 publications

Trojan Horse estimate of bare nucleus astrophysical S(E)-factor for the $\mathsf{^{6}}$Li(p,α)$^{\mathsf{3}}$He reaction and its astrophysical implications

Trojan Horse estimate of bare nucleus astrophysical S(E)-factor for the $\mathsf{^{6}}$Li(p,α)$^{\mathsf{3}}$He reaction and its astrophysical implications

Isotopic dependence of electron screening in fusion reactions

AN UPDATED6Li(p, α)3He REACTION RATE AT ASTROPHYSICAL ENERGIES WITH THE TROJAN HORSE METHOD

Contact Info

Product

Resources

About

AN UPDATED⁶Li(p, α)³He REACTION RATE AT ASTROPHYSICAL ENERGIES WITH THE TROJAN HORSE METHOD