Propagation and energy deposition of cosmic rays' muons on terrestrial environments

TL;DR

This paper investigates how high-energy cosmic ray muons penetrate Earth's atmosphere, water, and crust, analyzing their potential biological impact and secondary particle production using simulation tools.

Contribution

It provides a detailed simulation-based analysis of muon penetration and interaction effects in Earth's environment, highlighting potential biological impacts from cosmic ray events.

Findings

Muons can penetrate deep underground and underwater environments.

Secondary particles from muon interactions may cause off-track biological damage.

Cosmic ray events could temporarily increase radiation exposure on Earth.

Abstract

Earth is constantly struck by radiation coming from the interstellar medium. The very low energy end of the spectrum is shielded by the geomagnetic field but charged particles with energies higher than the geomagnetic cutoff will penetrate the atmosphere and are likely to interact, giving rise to secondary particles. Some astrophysical events, such as gamma ray bursts and supernovae, when happening at short distances, may affect the planet's biosphere due to the temporary enhanced radiation flux. Muons are abundantly produced by high energy cosmic rays in the Earth's atmosphere. These particles, due to their low cross section, are able to penetrate deep underground and underwater, with the possibility of affecting biological niches normally considered shielded from radiation. We investigate the interaction of muons produced by high energy cosmic rays on Earth's atmosphere using the Geant4 toolkit. We analyze penetration power in water and crust and also the interaction effects within bacteria-like material according to particle type and energy, and notice the possibility of off-track damage due to secondary particles.