Speaker
Description
Level densities are an important input to the Hauser-Feshbach theory of compound-nucleus reactions. Compound-nucleus reactions have numerous applications, including stellar nucleosynthesis and the design of next-generation nuclear reactors.
The microscopic calculation of level densities in the presence of correlations is a challenging many-body problem. The configuration-interaction shell model provides a suitable framework for the inclusion of correlations, but the large dimensionality of the many-particle model space has hindered its application in heavy nuclei. The shell model Monte Carlo (SMMC) method enables calculations in model spaces that are many orders of magnitude larger than spaces that can be treated by conventional diagonalization methods. The SMMC has been applied to nuclei as heavy as the lanthanides.
We have recently extended the SMMC method to the actinides. The actinides present several technical challenges when compared with the lanthanides: the required valence single-particle model space is larger, and the lower first excitation energy requires larger values of the imaginary time (or inverse temperature) to cool the nucleus to its ground state. Here, we present the first SMMC results for nuclear level densities up to the neutron separation energies in several even-even actinides and compare with available experimental results.
This work is supported in part by the U.S. DOE grant No. DE-SC0019521.
