Münster 2002 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 18: Nuclear and Particle Astrophysics II
HK 18.4: Vortrag
Dienstag, 12. März 2002, 17:45–18:00, C
Determination of the (n,γ) reaction rate of unstable 185W in the astrophysical s-process via its inverse reaction — •K. Sonnabend, P. Mohr, K. Vogt, M. Babilon, W. Bayer, D. Galaviz, T. Hartmann, C. Hutter, S. Volz, and A. Zilges — Institut für Kernphysik, Technische Universität Darmstadt, D-64289 Darmstadt, Germany
The β-unstable isotope 185W is a branching point in the
astrophysical s-process. Therefore the ratio of the
(n,γ) reaction rate and β-decay rate of 185W
is of common interest. We have measured the inverse
reaction 186W(γ,n)185W due to the experimental
difficulties in measuring the (n,γ) reaction rate
of an unstable isotope directly. Our preliminary result
is in agreement with theoretical predictions for the
(γ,n) cross section [1] and available data [2-4]. Therefore,
the predicted (n,γ) cross section under s-process conditions of
about 700 millibarn and the derived neutron density [5] are confirmed.
* supported by the DFG (contracts
Zi510/2-1 and FOR272/2-1)
[1] T. Rauscher, F.-K. Thielemann, At. Data Nucl. Data Tables 75, 1 (2000)
[2] B.L. Berman et al., Phys. Rev. 185, 1576 (1969)
[3] A.M. Goryachev, G.N. Zalesnyĭ, IZV. An. KazSSR 6, 8 (1978)
[4] G.M. Gurevich et al., Nucl. Phys. A351, 257 (1981)
[5] F. Käppeler et al., ApJ. 366, 605 (1991)