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HK: Fachverband Physik der Hadronen und Kerne

HK 49: Nukleare Astrophysik

HK 49.1: Gruppenbericht

Donnerstag, 20. März 2014, 16:30–17:00, HZ 5

Underground nuclear astrophysics in Europe: a status update — •Daniel Bemmerer — Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden

The cross sections of nuclear reactions taking place in stars and in the Big Bang are generally so low that they can only be measured in the low-background environment of an underground accelerator. The talk will report about progress achieved in the past year at the world’s only such machine, the LUNA 0.4 MV accelerator in Gran Sasso/Italy. The ²H(α,γ)⁶Li cross section has been measured for the first time directly in the Big Bang energy region, pinning down the amount of primordial ⁶Li. Measurements of the ¹⁷O(p,α)¹⁴N and ²²Ne(p,γ)²³Na cross sections important for nucleosynthesis in an astrophysical nova are underway at LUNA, and preliminary data at unprecedented low energies are already available. An activation study of the ⁴⁰Ca(α,γ)⁴⁴Ti reaction using offline counting in the Felsenkeller underground laboratory in Dresden has yielded new and more precise resonance strengths. In order to apply the method of underground nuclear astrophysics to topics such as helium and carbon burning and the neutron sources for the astrophysical s-process, it is necessary to install a higher-energy accelerator underground. The status of the relevant new accelerator projects at Gran Sasso and at Felsenkeller will be reported. – Supported by DFG (BE 4100/2-1) and NAVI (HGF VH-VI-417).