Badhwar-O'Neill 2020 Galactic Cosmic Ray Model (BON2020) v2.3(MSC-26835-1)

The BadhwarO'Neill (BON) model has been used for some time to describe the galactic cosmic ray (GCR) environment encountered in deep space by astronauts and sensitive electronics. This package contains the BON2020 model. The previous version of the model, BON2014, was calibrated to available measurements to reduce model errors for particles and energies of significance to astronaut exposure. Although subsequent studies showed the model to be reasonably accurate for such applications, modifications to the sunspot number (SSN) classification system and a large number of new highprecision measurements suggested the need to develop an improved and more capable model. The new BON2020 model relies on daily integral flux from the Advanced Composition Explorer Cosmic Ray Isotope Spectrometer (ACE/CRIS) to describe solar activity. For time periods not covered by ACE/CRIS, the updated international SSN database is used. Parameters in the new model are calibrated to available data, which include the new Alpha Magnetic Spectrometer (AMS02) and Payload for Antimatter Matter Exploration and Lightnuclei Astrophysics (PAMELA) highprecision measurements. It is found that the BON2020 model is a significant improvement over BON2014. Systematic bias associated with BON2014 has been removed. The average relative error of the BON2020 model compared to all available measurements is found to be <1%, and BON2020 is found to be within 15% of a large fraction of the available measurements (26,269 of 27,646 95%).