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. Author manuscript; available in PMC: 2020 Jan 1.
Published in final edited form as: Int J Radiat Biol. 2019 Jun 10;95(7):985–998. doi: 10.1080/09553002.2019.1623427

Figure 1.

Figure 1.

Cosmic ray energy and charge composition, and absorbed doses in the brain. (A) Proton energy spectra comparisons of model to measurements near-Earth for several time periods and for the local inter-stellar (LIS) environments. (B) Iron particle energy spectra comparisons of model to measurements near-Earth for several time period and for the local inter-stellar environments. (C) The contribution of protons, helium and several heavy ion charge groups to annual brain doses for average spacecraft shielding (10 g/cm2 aluminum). Model calculations for different times in the solar cycle and for the LIS spectra are shown. (D) The attenuation of cosmic ray doses charge numbers Z=1,2 (protons and helium) and Z>2 (heavy ions) versus tissue depth. Results show that doses do not vary appreciably for different brain regions.