The new KADoNiS v1.0 and its influence on the weak s-process nucleosynthesis

Iris Dillmann, Ralf Plag, Franz Käppeler, Alberto Mengoni, Christian Heinz, Marco Pignatari

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Abstract

Five years after the release of KADoNiS v0.3 (www.kadonis.org), a major update on the s-process database has been completed and is presently available for testing at HTTP://EXP-ASTRO.PHYSIK.UNI-FRANKFURT.DE/KADONIS1.0/. All available datasets between1H and210Bi and their energy dependence for kT= 5 - 100 keV have been reviewed, updated, and evaluated. The main difference to previous releases of KADoNiS is the intensive work that has been put in the inclusion of new experimental energy-dependent cross sections which should make the extrapolations to higher and lower energies more reliable. Also a revision of the197Au(n,γ) cross section has been applied which is widely used as reference cross section for time-of-flight and activation measurements. Several recent measurements in the astrophysical energy range have led to a new recommended value used throughout KADoNiS v1.0 which is 3-5.4% higher than the previously adopted value. Datasets for the up to now missing light stable isotopes6Li,10,11B, and17O were added and recommendations based on experimental data given. The total number of datasets in the KADoNiS database increased from 370 to more than 440 which is mainly due to the inclusion of radioactive isotopes 1-2 mass units away from stability. Although no measurements are available for these cases, they play an important role in modern s-process calculations with higher neutron densities. To be able to use a consistent database for s-process simulations it was decided to include these isotopes in the new update and calculate semi-empirical recommended cross sections. In this update also indirect measurements, namely (γ,n) measurements complemented by Hauser-Feshbach predictions with constrained input, have been included which yielded new (n,γ) recommended values for e.g. the branchings at85Kr,185W, and186Re. For other branching isotopes, e.g.63Ni, first direct experimental time-of-flight data yielded a factor of 2 higher cross section compared to the previously used theoretical prediction. The influences of the changes of the new (n,γ) cross sections on the weak s-process have been investigated. Whereas the differences after core He burning are within 20%, the impact of the new set of MACS on the s-process abundance distribution is much larger at the end of the shell C burning which leads to a "weaker" s-process efficiency.
Original languageEnglish
Publication statusPublished - 2014
Externally publishedYes
Event13th Nuclei in the Cosmos, NIC 2014 - Debrecen, Hungary
Duration: 1 Jan 2014 → …

Conference

Conference13th Nuclei in the Cosmos, NIC 2014
CountryHungary
CityDebrecen
Period1/1/14 → …

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Cite this

Dillmann, I., Plag, R., Käppeler, F., Mengoni, A., Heinz, C., & Pignatari, M. (2014). The new KADoNiS v1.0 and its influence on the weak s-process nucleosynthesis. Paper presented at 13th Nuclei in the Cosmos, NIC 2014, Debrecen, Hungary.