Destruction of26Al in explosive nucleosynthesis

Trautvetter, H. P.; Becker, Hans‐Werner; Heinemann, U.; Buchmann, L.; Rolfs, C.; Käppeler, F.; Baumann, Max Peter; Freiesleben, H.; Geltenbort, P.; Gönnenwein, F.

doi:10.1007/bf01294550

Cited by 14 publications

(35 citation statements)

References 22 publications

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“…The first experiment (run 1, Table 1) was carried out using a close-geometry setup similar to that described recently [12]. The target consisted here of 210_+21 gg/cm 2 of melamine (Sect.…”

Section: Methodsmentioning

confidence: 99%

“…Furthermore, because of the low count rates expected for the above neutron flux at keV neutron energies, it was also necessary to maximize the solid angle of the detector system (here: a Si surface barrier detector), and the detector had therefore to be exposed to the neutron beam. In order to minimize the resulting neutron-induced background in the Si detector (i.e., to improve the signal-to-background yield ratio), thin transmission Si detectors were used [12].…”

Section: Methodsmentioning

confidence: 99%

“…I b, where a cylindrical 14N target volume faces a coaxially mounted Si detector in close geometry, was determined by a Monte-Carlo calculation [15]. It has been shown for similar close geometries [12] that such calculations are reliable to better than 4%. The results are summarized in Table I.…”

Section: Target Thickness T and Areal Number Density Ntmentioning

confidence: 99%

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The cross section of14N(n, p)14C at stellar energies and its role as a neutron poison forS-process nucleosynthesis

Brehm

Becker

Rolfs

et al. 1988

Z. Physik A - Atomic Nuclei

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The absolute average cross section (o-) of the 14N(n, p) 14C reaction has been measured using neutron spectra that closely resemble Maxwell-Boltzmann distributions with thermal energies of kT = 25.0 and 52.4 keV: (o-) = 0.81 ___ 0.05 and 0.52 4-0.06 mb, respectively. The resulting reaction rates are nearly the same at T9=0.29 and 0.61, and their average, NA (o-v) = (1.3 _+ 0.1) x 105 cm 3 s-1 mol-1, is about a factor of three smaller than the previously adopted values obtained by extrapolation between thermal and higher-energy data. Thus, the 14N(n, p) 14C reaction plays a correspondingly smaller role as a neutron poison for s-process nucleosynthesis.

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“…The first experiment (run 1, Table 1) was carried out using a close-geometry setup similar to that described recently [12]. The target consisted here of 210_+21 gg/cm 2 of melamine (Sect.…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

The cross section of14N(n, p)14C at stellar energies and its role as a neutron poison forS-process nucleosynthesis

Brehm

Becker

Rolfs

et al. 1988

Z. Physik A - Atomic Nuclei

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“…The determination of the 26 Al t (n, p) 26 Mg reaction rate actually requires the independent measurements of two reactions: 26 Al g (n, p) 26 Mg and 26 Al m (n, p) 26 Mg. Two direct measurements of 26 Al g (n, p) 26 Mg have been published up to now, using 26 Al g targets (Trautvetter et al 1986;Koehler et al 1997). Their results differ by a factor of 2, calling for more experimental work.…”

Section: Uncertainties In the Relevant Reaction Ratesmentioning

confidence: 99%

The radioactive nuclei and in the Cosmos and in the solar system

Diehl

Lugaro

Heger

et al. 2021

Publ. Astron. Soc. Aust.

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The cosmic evolution of the chemical elements from the Big Bang to the present time is driven by nuclear fusion reactions inside stars and stellar explosions. A cycle of matter recurrently re-processes metal-enriched stellar ejecta into the next generation of stars. The study of cosmic nucleosynthesis and this matter cycle requires the understanding of the physics of nuclear reactions, of the conditions at which the nuclear reactions are activated inside the stars and stellar explosions, of the stellar ejection mechanisms through winds and explosions, and of the transport of the ejecta towards the next cycle, from hot plasma to cold, star-forming gas. Due to the long timescales of stellar evolution, and because of the infrequent occurrence of stellar explosions, observational studies are challenging, as they have biases in time and space as well as different sensitivities related to the various astronomical methods. Here, we describe in detail the astrophysical and nuclear-physical processes involved in creating two radioactive isotopes useful in such studies, $^{26}\mathrm{Al}$ and $^{60}\mathrm{Fe}$ . Due to their radioactive lifetime of the order of a million years, these isotopes are suitable to characterise simultaneously the processes of nuclear fusion reactions and of interstellar transport. We describe and discuss the nuclear reactions involved in the production and destruction of $^{26}\mathrm{Al}$ and $^{60}\mathrm{Fe}$ , the key characteristics of the stellar sites of their nucleosynthesis and their interstellar journey after ejection from the nucleosynthesis sites. This allows us to connect the theoretical astrophysical aspects to the variety of astronomical messengers presented here, from stardust and cosmic-ray composition measurements, through observation of $\gamma$ rays produced by radioactivity, to material deposited in deep-sea ocean crusts and to the inferred composition of the first solids that have formed in the Solar System. We show that considering measurements of the isotopic ratio of $^{26}\mathrm{Al}$ to $^{60}\mathrm{Fe}$ eliminate some of the unknowns when interpreting astronomical results, and discuss the lessons learned from these two isotopes on cosmic chemical evolution. This review paper has emerged from an ISSI-BJ Team project in 2017–2019, bringing together nuclear physicists, astronomers, and astrophysicists in this inter-disciplinary discussion.

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“…Constraining destruction rates of 26 Al (t 1/2 = 7.2×10 5 y) via (n, p) (and (n, α)) in convective shell C/Ne Burning and explosive Ne/C burning is expected to dominate the uncertainties of 26 Al production in those sites [20], which is an important observable for γ-ray astronomy [21]. Even though the importance of these rates is known for a long time, only few measurements were performed at stellar energies [22][23][24], of which only a single measurement was performed at the relevant energies for explosive scenarios, and it only covered a portion of the relevant energy region: 270-350 keV [22], hence these rates still require investigation at explosive stellar temperatures [1,20]. The suggested method in this paper can be used to measure this reaction using available facilities.…”

Section: Specific Application Examplesmentioning

confidence: 99%

Production of Quasi-Stellar Neutron Field at Explosive Stellar Temperatures

Friedman

2020

Preprint

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Neutron-induced reactions on unstable isotopes play a key role in the nucleosynthesis i-, r-, p-, rp-and νp-processes occurring in astrophysical scenarios. While direct cross section measurements are possible for long-living unstable isotopes using the neutron Time-of-Flight method, the currently available neutron intensities (≈ 10 6 n/s) require large samples which are not feasible for shorter lifetime isotopes. For the last four decades, the 7 Li(p, n) reaction has been used to provide a neutron field at a stellar temperature of ≈ 0.3 GK with significantly higher intensity, allowing the successful measurement of many cross sections along the s-process path. In this paper we describe a novel method to use this reaction to produce neutron fields at temperatures of ≈ 1.5-3.5 GK, relevant to scenarios such as convective shell C/Ne burning, explosive Ne/C burning, and corecollapse supernovae. This method will allow direct cross section measurements of many important reactions at explosive temperatures, such as 26 Al(n, p), 75 Se(n, p) and 56 Ni(n, p).

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Destruction of26Al in explosive nucleosynthesis

Cited by 14 publications

References 22 publications

The cross section of14N(n, p)14C at stellar energies and its role as a neutron poison forS-process nucleosynthesis

The cross section of14N(n, p)14C at stellar energies and its role as a neutron poison forS-process nucleosynthesis

The radioactive nuclei and in the Cosmos and in the solar system

Production of Quasi-Stellar Neutron Field at Explosive Stellar Temperatures

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