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HK: Hadronen und Kerne
HK 39: Nuclear Astrophysics III
HK 39.6: Talk
Tuesday, March 17, 1998, 18:30–18:45, E
Neutron Capture of 26Mg: Direct Capture and Resonances * — •P. Mohr1, H. Beer2, and H. Oberhummer3 — 1Institut f"ur Kernphysik, Technische Universit"at Darmstadt, Schlossgartenstraße 9, D–64289 Darmstadt — 2Forschungszentrum Karlsruhe, Institut f"ur Kernphysik III, P.O.Box 3640, D–76021 Karlsruhe — 3Institut f"ur Kernphysik, Technische Universit"at Wien, Wiedner Hauptstraße 8–10, A–1040 Wien
For the nucleosynthesis of heavy nuclei neutron capture reactions play a key role (s-, r-, α-process). The cross section for neutron capture is usually composed of resonant capture (RC) in compound states and direct capture (DC). The DC can be determined experimentally only for light neutron-rich nuclei; for many stable nuclei the RC is dominating. However, the DC becomes important for very neutron-rich nuclei, e.g. in the r-process. In a series of experiments performed at the 3.75 MV Van de Graaff accelerator in Karlsruhe we have analyzed the DC of several light neutron-rich nuclei at thermonuclear energies [1] using the fast cyclic activation technique [2].
In the case of 26Mg the DC was measured between the known resonances, and for the resonance strengths a severe disagreement between our experiment and a previous result [3] was found.
[1] P. Mohr et al., Phys. Rev. C 56, 1154 (1996), and references therein.
[2] H. Beer et al., Nucl. Inst. Meth. A 337, 492 (1994).
[3] H. Weigmann et al., Phys. Rev. C 14, 1328 (1976).
*Supported by DFG (Mo739/1–1) and FWF (S7307/AST)