On the Energy Spectrum of Cosmogenic Neutrons

TL;DR

This paper models the energy spectrum of cosmogenic neutrons produced underground by cosmic-ray muons, explaining its shape and the energy 'knee' dependence on atomic mass, and compares calculations with measurements.

Contribution

It introduces a model for the energy spectrum of cosmogenic neutrons based on deep-inelastic pion-nucleus interactions and explains the spectrum's shape and features.

Findings

Spectrum has a three-component shape with a knee depending on atomic mass.

Spectrum steepens sharply above 1 GeV due to deep-inelastic scattering peculiarities.

Calculated spectrum characteristics agree with experimental measurements.

Abstract

The processes of the generation of cosmogenic neutrons (cg-neutrons) underground are considered. The neutrons produced by cosmic-ray muons in their interactions with matter are called cosmogenic. Deep-inelastic ${\pi}A$-collisions of pions in muon-induced hadronic showers are mainly their source at energies above 30 MeV. The characteristics of the energy spectrum for the generation of cg-neutrons have been determined by invoking the additive quark model of deep-inelastic soft processes and the mechanism for the interactions of high-energy nucleons in a nucleus. The three-component shape of the spectrum is explained, and the energy of the "knee" in the spectrum has been found to depend on the mass number $A$. The peculiarities of deep-inelastic ${\pi}A$-scattering lead to the conclusion that the spectrum of cg-neutrons steepens sharply at energies above 1 GeV. The calculated quantitative characteristics of the spectrum are compared with those obtained in measurements.