Abstract
By extending our previously established model, here we present a new model called “PHITS-based Analytical Radiation Model in the Atmosphere (PARMA) version 3.0,” which can instantaneously estimate terrestrial cosmic ray fluxes of neutrons, protons, ions with charge up to 28 (Ni), muons, electrons, positrons, and photons nearly anytime and anywhere in the Earth’s atmosphere. The model comprises numerous analytical functions with parameters whose numerical values were fitted to reproduce the results of the extensive air shower (EAS) simulation performed by Particle and Heavy Ion Transport code System (PHITS). The accuracy of the EAS simulation was well verified using various experimental data, while that of PARMA3.0 was confirmed by the high R 2 values of the fit. The models to be used for estimating radiation doses due to cosmic ray exposure, cosmic ray induced ionization rates, and count rates of neutron monitors were validated by investigating their capability to reproduce those quantities measured under various conditions. PARMA3.0 is available freely and is easy to use, as implemented in an open-access software program EXcel-based Program for Calculating Atmospheric Cosmic ray Spectrum (EXPACS). Because of these features, the new version of PARMA/EXPACS can be an important tool in various research fields such as geosciences, cosmic ray physics, and radiation research.
Highlights
Galactic cosmic rays are continuously incident on the Earth, and they induce extensive air shower (EAS) by successively causing nuclear and atomic interactions in the atmosphere
Considering these situations, we developed an analytical model for estimating terrestrial cosmic ray fluxes under any global condition, with the exception of altitudes higher than 20 km [20,21], by modeling the results of an EAS simulation performed using the Particle and Heavy Ion Transport Code System (PHITS) [22]
Based on the results of the EAS simulation conducted using Particle and Heavy Ion Transport code System (PHITS), we developed PARMA3.0, which facilitates instantaneous estimation of terrestrial cosmic ray fluxes nearly anytime and anywhere in the Earth’s atmosphere
Summary
Galactic cosmic rays are continuously incident on the Earth, and they induce extensive air shower (EAS) by successively causing nuclear and atomic interactions in the atmosphere. Evaluation of the temporal and locational variations of cosmic ray fluxes generated through EAS is very important for estimating cosmogenic nuclide yields, radiation doses for aircrews, and soft-error rates of semi-conductor devices. Monte Carlo methods can give better estimates in comparison with analytical methods, but they require considerable computational resources. This drawback prevents the direct incorporation of Monte Carlo methods into a system for rapidly evaluating terrestrial cosmic ray fluxes at various altitudes, geomagnetic locations, and solar activities (referred to here as global conditions). Modeling or database creation is required to use the results of the Monte Carlo simulations in those systems
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
