Light fragment and neutron emission in high-energy proton induced spallation reactions

TL;DR

This paper investigates high-energy proton-induced spallation reactions on various targets using a quantum molecular dynamics model combined with statistical decay and cluster emission models, achieving good agreement with experimental cross sections.

Contribution

It introduces a combined modeling approach with surface coalescence and quantum tunneling to better simulate light fragment and neutron emission in spallation reactions.

Findings

Accurately reproduces total cross sections for heavy and light targets.

Identifies the main contribution of energetic clusters from preequilibrium processes.

Discusses discrepancies and potential improvements in modeling spallation reactions.

Abstract

The dynamics of high-energy proton-induced spallation reactions on target nuclides of $^{136}$Xe, $^{59}$Ni, $^{56}$Fe, $^{208}$Pb, $^{184}$W, $^{181}$Ta, $^{197}$Au and $^{112}$Cd, are investigated with the quantum molecular dynamics transport model. The production mechanism of light nuclides and fission fragments is thoroughly analyzed. The statistical code GEMINI is employed in conjunction to the model for managing the decay of primary fragments. For the treatment of cluster emission during the preequilibrium stage, a surface coalescence model is implemented into the model. It is found that the available data of total cross sections are well reproduced with the combined approach for the spallation reactions on both the heavy and light targets, i.e., $^{56}$Fe and $^{208}$Pb, while it is underestimated in the intermediate-mass-fragment region for the medium-mass target $^{136}$Xe. The energetic clusters are mainly contributed from the preequilibrium recognition, in which the quantum tunneling is taken into account. On the other hand, a fairly well overall description of light cluster and neutron emission is obtained and detailed discrepancies with respect to the experimental results are discussed. Possible modifications on the description of spallation reactions are stressed and compared with both recent experimental and theoretical results in the literature.