Eur. Phys. J. A (2020) 56: 84
https://doi.org/10.1140/epja/s10050-020-00059-2

Regular Article -Theoretical Physics

Systematics of different quantities related to sequential prompt emission in fission

University of Bucharest, Faculty of Physics, 405 Atomistilor str., Magurele, POB MG-11, 77125, Bucharest, Romania

^* e-mail: anabellatudora@hotmail.com

Received: 14 July 2019
Accepted: 27 December 2019
Published online: 18 March 2020

Abstract

A deterministic treatment of sequential neutron emission, based on recursive equations of the residual temperatures, was applied to numerous fission cases (i.e. 49 cases including nuclei fissioning spontaneously or induced by thermal and fast neutrons) for which reliable experimental data of fragment distributions exist. This fact emphasizes systematics and correlations between different average quantities characterizing the initial and residual fission fragments and the sequential prompt neutron emission. The ratios of the average residual temperature following the emission of each neutron to the average temperature of initial fragments () are almost constant for all studied fission cases. They do not depend on the prescriptions used for the compound nucleus cross-sections of the inverse process and the level density parameters of initial and residual fragments. This finding allows the determination of a general form of the residual temperature distribution for each emission sequence with the maximum temperature related only to the average temperature of initial fragments. In this way the sequential emission can be included into the Los Alamos model. Prompt neutron spectra in the center-of-mass and laboratory frames can be calculated for each emission sequence. The systematic of the ratios of average residual temperatures and energies to the initial ones together with other linear correlations between different prompt emission and residual quantities allow to obtain indicative values of different average prompt emission quantities in the absence of any prompt emission model.