Systematic study of actinide and pre-actinide fission modes

TL;DR

This paper presents new experimental data and a systematic analysis of actinide and pre-actinide fission fragment mass distributions across various reactions and energies, using the Random Neck Rupture Model to understand underlying nuclear mechanisms.

Contribution

It provides comprehensive experimental results and applies the Random Neck Rupture Model to analyze fission modes in actinides and pre-actinides, exploring the roles of neutron excess and fissility.

Findings

New mass distribution data for $^{241}$Am fission at 660 MeV.

Systematic comparison of multiple fission reactions and energies.

Insights into neutron excess and fissility effects on fission modes.

Abstract

In this work, we present new experimental data on mass distribution of fission fragments from $^{241}$Am proton-induced fission at $660$ MeV measured at the LNR Phasotron (JINR). The systematic analysis of several measured fragment mass distributions from different fission reactions available in the literature is also presented. The proton-induced fission of $^{241}$Am, $^{237}$Np and $^{238}$U at 26.5, 62.9 and 660 MeV was studied. The proton-induced fission of $^{232}$Th was studied at 26.5, 62.9 and 190 MeV. The fission of $^{208}$Pb also by a proton was investigated at 190, 500 and 1000 MeV. The fission of $^{197}$Au was studied for 190 and 800 MeV protons. Bremsstrahlung reactions with maximum photon energies of 50 and 3500 MeV were studied for $^{232}$Th and $^{238}$U. The framework of the Random Neck Rupture Model was applied in the analysis. The roles of the neutron excess and of the so called fissility parameter were also investigated.