Eur. Phys. J. A (2006) 27: 129-134
https://doi.org/10.1140/epja/i2006-08-018-5

Nuclear Physics in Astrophysics II

(n,γ) cross-sections of light p nuclei

Towards an updated database for the p process

¹ Institut für Kernphysik, Forschungszentrum Karlsruhe, Postfach 3640, D-76021, Karlsruhe, Germany
² Departement Physik und Astronomie, Universität Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland

^* e-mail: iris.dillmann@ik.fzk.de

Received: 7 July 2005
Accepted: 20 December 2005
Published online: 10 March 2006

Abstract

The nucleosynthesis of elements beyond iron is dominated by the s and r processes. However, a small amount of stable isotopes on the proton-rich side cannot be made by neutron capture and is thought to be produced by photodisintegration reactions on existing seed nuclei in the so-called “p process”. So far most of the p-process reactions are not yet accessible by experimental techniques and have to be inferred from statistical Hauser-Feshbach model calculations. The parametrization of these models has to be constrained by measurements on stable proton-rich nuclei. A series of (n,γ) activation measurements on p nuclei, related by detailed balance to the respective photodisintegrations, was carried out at the Karlsruhe Van de Graaff accelerator using the ⁷Li(p, n) ⁷Be source for simulating a Maxwellian neutron distribution of kT = 25keV. We present here preliminary results of our extended measuring program in the mass range between A = 74 and A = 132, including first experimental (n,γ) cross-sections of ⁷⁴Se, ⁸⁴Sr, ¹²⁰Te and ¹³²Ba, and an improved value for ¹³⁰Ba. In all cases we find perfect agreement with the recommended MACS predictions from the Bao et al. compilation.