Development of gamma de-excitation model for prediction of prompt gamma-rays and isomer production based on energy-dependent level structure treatment

摘要

A new theoretical model to simulate gamma de-excitation of excited nuclei, EBITEM (ENSDF-Based Iso-meric Transition and isomEr production Model), is developed based on the Evaluated Nuclear Structure Data File (ENSDF), supplementary evaluated data tables, and theories. In the model, reaction products after nucleon evaporation were de-excited by using theoretical calculations if the excitation energy was higher than 3000 keV and the mass number was greater than 40 amu. Otherwise, the nuclei were de-excited based on the scheme provided in the ENSDF. Thus by tracking nuclear de-excitation, production of prompt gamma-rays and isomers was simulated. The model is applicable for neutron capture products and spallation products of 1071 nuclear species from Li to Bk. Except for some of the light nuclei with discrete level structure, simulated isomer production and prompt gamma-ray spectra agree generally within 40% and a factor of 3, respectively.