Systematics and Determination of Level Density Parameters of Fission Product Nuclei

Abstract

Nuclear level density parameters of fission product nuclei were determined in a consistent way with experimental neutron resonance data and level scheme data. The composite level density formula of Gilbert & Cameron was used with a revised expression of spin cut-off factor. The systematic trends in the determined parameters were investigated in detail. In addition to the parameter systematics used hitherto, two new phenomenological systematics were proposed and discussed. These systematics were fully used to estimate the level densities of nuclei whose experimental data are lacking. Parameters of about 130 nuclei were determined to form an extensive data base for calculation of neutron cross sections of fission products.

KEYWORDS:

• fission products
• neutron cross sections
• computer calculations
• level density parameters
• Gilbert-Cameron's formula
• revised spin cutoff factor
• parameter determination
• systematics study
• systematics
• parameter data base
• nuclear data