Analytical model for estimating terrestrial cosmic ray fluxes nearly anytime and anywhere in the world; Extension of PARMA/EXPACS

Sato, Tatsuhiko   

By extending our previously established model, here we propose 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 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.