Random files for fission fragment evaporation in TALYS: a total Monte Carlo approach

Abstract In this study, we have applied the Total Monte Carlo (TMC) methodology in the simulation of the de-excitation process of primary fission fragments (FF) within the TALYS code. Our objective was to develop a method for assessing fission model deficiencies and parameter sensitivities. The input fission fragment data used by TALYS were systematically varied. This was done using the GEF code to generate 10,000 random files by randomizing the 94 model parameters of GEF that influence both fission yields and their energy distributions. The GEF parameters were varied randomly within 3% of the default value, assuming a normal probability distribution. As a result of this parameter variation, significant changes could be identified for several observables, including the multiplicities of $$\gamma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>γ</mml:mi> </mml:math> rays and prompt neutrons, as well as their spectra. Additionally, we investigate the impact of angular momentum distribution on the de-excitation data of both GEF and TALYS. Finally, we present an attempt to construct a best parameter file benchmarked against evaluated nuclear data files.