Session T7 - Nuclear Reactions: Light Ions and Nuclear Astrophysics.
ORAL session, Tuesday morning, April 08
Regency Ballroom C1, Loews Philadelphia Hotel
The treatment of excited states of nuclei in astrophysical rate calculations has traditionally relied on the Hauser-Feshbach formalism. The assumption is that thermalization has occured, which may not be valid if the presence of a low-lying isomer necessitates investigation into the nonequilibrium behavior of the nucleus under realistic stellar conditions. A technique for appropriately splitting such nuclei into interacting ensembles which are in equilibrium throughout the evolution is presented. The technique is used in consonance with the Hauser-Feshbach formalism to track the effective internal transition and the decay/capture rates of nuclei when they are not in equilibrium. Finally we transform the ENSDF online datasets into machine-readable format and allow the interactive calculation of rates for user-selected combinations of experimental and theoretical data pertaining to nuclei upto A=250. Theoretical level densities from the Intitute of Astrophysics (Brussels) are used to supplement the ENSDF experimental level-schemes. An interactive website is presented to display the formalism as implemented for beta decays of nuclei important to astrophysics.