Gamma-ray strength functions and their relation to astrophysics
3rd International Conference on Frontiers in Nuclear Structure, Astrophysics and Reactions (FINUSTAR), Rhodes, Greece, 23 - 27 August 2010, vol.1377, pp.239-246, (Full Text)
- Publication Type: Conference Paper / Full Text
- Volume: 1377
- Doi Number: 10.1063/1.3628386
- City: Rhodes
- Country: Greece
- Page Numbers: pp.239-246
- Eskisehir Osmangazi University Affiliated: Yes
Abstract
The nuclear gamma-ray strength function is one of the indispensable inputs needed for reaction-rate calculations, and is particularly important for the neutron-capture cross section. The nuclear physics group at the Oslo Cyclotron Laboratory has developed a method to extract simultaneously nuclear level density and gamma-ray strength function from particle-gamma coincidence measurements. Data on the strength functions of Sn nuclei as well as for lighter elements are presented. The Sn isotopes all display a resonance-like structure close to the neutron threshold, that could possibly be due to the neutron-skin oscillation mode. This so-called pygmy dipole resonance greatly influences the neutron-capture rates. In the lighter nuclei, an enhancement of the strength function at low gamma energies is observed. The possible impact of this increase on Maxwellian-averaged reaction rates has been investigated.