Bochum 1998 – wissenschaftliches Programm
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HK: Hadronen und Kerne
HK 56: Postersitzung
HK 56.16: Poster
Mittwoch, 18. März 1998, 17:00–19:00, Foyer
Investigation of the 17O(nth,α)14N reaction — •Jan Wagemans1, Cyriel Wagemans2, Ronald Bieber1, and Peter Geltenbort3 — 1Institute for Reference Materials and Measurements, Retieseweg, B-2440 Geel — 2Dept. of Subatomic and Radiation Physics, University, Proeftuinstraat 86, B-9000 Gent — 3Institut Laue-Langevin, BP 156, F38042 Grenoble Cedex 9, France
The 17O(nth,α)14N reaction plays a role in various scenario’s in nuclear astrophysics, but there are doubts concerning its cross-section. Especially for the thermal cross-section, only two values are reported in the literature, i.e. (235±5)mb and (560±130)mb. In order to accurately determine the 17O(nth,α) cross-section, we installed a dedicated set-up at the end of the thermal neutron guide H22D of the high flux reactor of the ILL. We developed a special technique using gaseous samples. First, a known volume of oxygen enriched in 17O is injected in a vacuum chamber in which a calibrated surface barrier detector is mounted to determine the 17O(nth,α) counting rate. Consequently, the oxygen is pumped away, an identical volume of air is injected and the 14N(nth,p) counting rate is determined. Since the 14N(nth,p) cross-section is well known, the 17O(nth,α)14N cross-section can be calculated by combining both counting rates. Measurements were performed with oxygen gas with an enrichment of 58.2% and 85.5%, resulting in a preliminary value of 240mb for the 17O(nth,α)14N cross-section.