Erlangen 2026 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 16: Nuclear Astrophysics II

HK 16.4: Gruppenbericht

Dienstag, 17. März 2026, 17:15–17:45, PHIL A 602

Study of the ¹⁴N(α, γ)¹⁸F reaction at Felsenkeller underground lab with the gas-jet target setup — •Anup Yadav^{1, 2}, Daniel Bemmerer¹, Konrad Schmidt¹, Eliana Masha¹, Axel Boeltzig¹, Peter Hempel^1,2, and Kai Zuber² — ¹Helmholtz-Zentrum Dresden-Rossendorf (HZDR) — ²Technische Universität Dresden

A precise reaction rate for ¹⁴N(α,γ)¹⁸F is required for modeling stellar evolution. The ¹⁴N(α,γ)¹⁸F reaction takes place during the helium-burning phase in asymptotic giant branch (AGB) stars other helium-burning sites. This reaction influences different nucleosynthesis pathways and is part of the reaction chains ¹⁴N(α,γ)¹⁸F(β⁺)¹⁸O(α,γ)²²Ne and ¹⁴N(α,γ)¹⁸F(β⁺)¹⁸O(p,α)¹⁵N(α,γ)¹⁹F, which are important for the production of ²²Ne and ¹⁹F, respectively. However, at helium-burning energies the cross section is dominated by low-energy resonances whose properties remain insufficiently constrained. The reaction was studied at the Felsenkeller shallow-underground laboratory using a newly developed gas-jet target setup, in which an α beam was directed onto a nitrogen gas jet and the emitted γ rays were detected with high-purity germanium detectors. Precise angular distributions, branching ratios, resonance energies, and strengths were measured for three selected resonances at E_r = 573, 1136, and 1618 keV, with the lowest-energy resonance being relevant for helium-burning temperatures. We will present the new experimental results and discuss their astrophysical impact. Future measurements using the gas-jet target at the Felsenkeller underground laboratory will also be outlined.

Keywords: Nuclear astrophysics; gas target; interferometry; cross section