Modeling high-energy cosmic ray induced terrestrial muon flux: A lookup table

Department of Physics and Astronomy, University of Kansas, 1251 Wescoe Dr. # 1082, Lawrence, KS 66045, United States
Radiation Physics and Chemistry (Impact Factor: 1.38). 11/2010; 80(6):701-703. DOI: 10.1016/j.radphyschem.2011.02.020
Source: arXiv

ABSTRACT On geological timescales, the Earth is likely to be exposed to an increased flux of high-energy cosmic rays (HECRs) from astrophysical sources such as nearby supernovae, gamma-ray bursts or by galactic shocks. Typical cosmic ray energies may be much higher than the flux which normally dominates. These high-energy particles strike the Earth's atmosphere initiating an extensive air shower. As the air shower propagates deeper, it ionizes the atmosphere by producing charged secondary particles. Secondary particles such as muons and thermal neutrons produced as a result of nuclear interactions are able to reach the ground, enhancing the radiation dose. Muons contribute 85% to the radiation dose from cosmic rays. This enhanced dose could be potentially harmful to the biosphere. This mechanism has been discussed extensively in literature but has never been quantified. Here, we have developed a lookup table that can be used to quantify this effect by modeling terrestrial muon flux from any arbitrary cosmic ray spectra with 10 GeV to 1 PeV primaries. This will enable us to compute the radiation dose on terrestrial planetary surfaces from a number of astrophysical sources.

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    • "The table was generated with 1.9 x 10 6 primaries. The muon flux generated from the lookup table data is in excellent agreement with the Hebbeker and Timmermans [2002] polynomial fit which itself is derived from a compilation of muon data from a number of experiments [Atri and Melott 2011]. "
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