| Full text | |
| Author(s): |
Oliveira, N. C. da Fonseca e
;
Dutra, M.
;
Carlson, B., V
;
Guimaraes, V
;
Genezini, F
;
Lubian, J
;
Assuncao, M
;
Delgado, A
;
Trevisan, LA
Total Authors: 9
|
| Document type: | Journal article |
| Source: | WAKE CONFERENCE 2021; v. 1291, p. 4-pg., 2019-01-01. |
| Abstract | |
Accurate level densities are an important ingredient in the calculation of compound nucleus emission cross sections. They are often approximated numerically using the saddle point approximation to the canonical level density obtained from the grand canonical partition function using the inverse Laplace transform. Here, we use a modified version of the saddle-point approximation proposed by Rossignoli to obtain canonical level densities and average properties of a system. However, the level density needed in nuclear reaction calculations is actually the energy-conserving microcanonical one. For simple systems, the latter can be calculated combinatorially. Here we calculate microcanonical level densities using an evenly-spaced single particle density for one type of nucleon and compare these to saddle-point canonical level densities obtained from the same single-particle density. The simplest continuous approximation to the microcanonical level density describes it well near its peak but poorly at low excitation energies. The canonical level density obtained from the partition function fares somewhat better but is still not completely successful. It tends to exceed the exact result by a few percent. We discuss the differences between the canonical and microcanonical level densities and suggest how these might be reduced. (AU) | |
| FAPESP's process: | 17/05660-0 - Theoretical studies of the structure and reactions of exotic nuclei and many-body systems |
| Grantee: | Brett Vern Carlson |
| Support Opportunities: | Research Projects - Thematic Grants |