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arXiv · 2511.09040

Time-Dependent Radiation Quality Factor of Galactic Cosmic Rays in Deep Space and Shielding Environments: Modeling and Measurements

Weihao Liu·Mikhail Dobynde·Jingnan Guo·Jordanka Semkova·Krasimir Krastev
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Abstract

Understanding the long-term variation of the galactic cosmic ray (GCR) radiation environment is critical for assessing radiation risks in space exploration missions. In this study, we systematically model the linear energy transfer (LET) spectra of GCRs and the corresponding radiation quality factor, , in deep space and shielding environments. The Badhwar-O'Neill 2020 (BON20) model is used to represent GCR fluxes under different solar modulation potentials (phi), which characterize the level of solar activity. GCR interactions with spherical shielding of different thicknesses are simulated to obtain the LET spectra, absorbed dose, dose equivalent, and . We present a comprehensive dataset of these quantities for a range of phi values and shielding thicknesses. The results show that depends strongly on the shielding thickness but only weakly on solar activity. Furthermore, model predictions are validated against long-term measurements from the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) orbiting the Moon, and the Liulin-MO detector on board the ExoMars Trace Gas Orbiter (TGO) orbiting Mars. In this comparison, we consider factors for anomalous cosmic ray (ACR) contributions and radial gradients of both GCRs and ACRs, applying scaling factors of 6.3% at 1 AU and 11.0% at 1.5 AU to the calculated absorbed dose rate. With these corrections, the modeled absorbed dose rate and exhibit consistent temporal variations with the observations under both thin and thick shielding conditions. Moreover, we investigate the distinct temporal evolution of for light and heavy GCR nuclei, revealing how solar modulation influences the elemental radiation quality factor across GCR species. These results offer new insights into the temporal and environmental dependence of the space radiation quality factor, with implications for radiation dose estimate and crewed mission design.

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Weihao Liu, Mikhail Dobynde, Jingnan Guo, Jordanka Semkova, Krasimir Krastev. 2025-12-01. Time-Dependent Radiation Quality Factor of Galactic Cosmic Rays in Deep Space and Shielding Environments: Modeling and Measurements. https://arxiv.org/abs/2511.09040

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