Bochum 1998 – wissenschaftliches Programm

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HK: Hadronen und Kerne

HK 56: Postersitzung

HK 56.17: Poster

Mittwoch, 18. März 1998, 17:00–19:00, Foyer

Resonances in the ³⁷Ar(n,α)³⁴S cross-section — •Gert Goeminne¹, Cyriel Wagemans¹, Ronald Bieber², Jan Wagemans², and Filip Kolen¹ — ¹Department of Subatomic and Radiation Physics, University of Gent, Proeftuinstraat 86, B-9000, Belgium — ²Institute of Reference Materials and Measurements, JRC, CEC, Retieseweg, B-2440, Belgium

The ³⁷Ar(n,α)³⁴S reaction plays a role in the stellar nucleosynthesis of nuclides in the S to Ar-region. Due to the short half-life of ³⁷Ar (35d), this reaction was never studied so far with resonance neutrons. At the linear accelerator GELINA of the IRMM in Geel, a dedicated set-up is available for the investigation of (n,α)-reactions as a function of the neutron energy. The detection of the α-particles is done with a methane-flow gridded ionization chamber. Despite the small number of ³⁷Ar atoms in the sample (2.5×10¹⁵ at the beginning of the experiment), two strong resonances could be identified. They occur at neutron energies of 1.6 keV and 2.8 keV, with peak cross-sections of a few hundred barn and resonance areas of the order of 40000 b.eV. This leads to very large values of the Maxwellian averaged cross-section (e.g. 4b at kT=8keV).