Systematic study of photoneutron reactions just above the photoneutron threshold

• Main Author: Hasper, Jens
• Format: Others
• Language: English; en
• Published: 2008
• Online Access: http://tuprints.ulb.tu-darmstadt.de/1011/1/Hasper_Systematic_study_of_photoneutron_reactions.pdf; Hasper, Jens <http://tuprints.ulb.tu-darmstadt.de/view/person/Hasper=3AJens=3A=3A.html> : Systematic study of photoneutron reactions just above the photoneutron threshold. Technische Universität, Darmstadt [Ph.D. Thesis], (2008)

This thesis deals with the systematic study of photoneutron reactions in the astrophysically relevant energy region just above the neutron threshold. Photodisintegration reactions play a decisive role in the nucleosynthesis of elements heavier than iron. A large number of proton-rich isotopes are believed to be exclusively produced by a combination of (γ,n), (γ,p) and (γ,α) reactions during supernova explosions in the so-called p process. Astrophysical network calculations of this process have to account for thousands of photodisintegration reaction rates which mainly need to be adopted from theoretical predictions. To test and improve the predictive power of these calculations, it is mandatory to provide reliable experimental data for those reactions which can be studied in the laboratory. Therefore, in the scope of this thesis, the photoneutron reactions of various isotopes have been measured in photoactivation experiments at the superconducting Darmstadt electron linear accelerator S-DALINAC. In particular, for the first time, experimental data have been provided for the photoneutron cross sections of rare-earth isotopes in the astrophysically relevant energy region. The experimental results will be compared with theoretical predictions of two statistical model codes and discussed with regard to their astrophysical implications.