Fluence to dose equivalent conversion coefficients for ICRP110 voxel phantoms with aluminum and polyethylene...

Fluence-to-dose-equivalent conversion coefficients are essential for assessing astronaut radiation exposure in space. In this study, we calculate these coefficients for the ICRP110 male and female voxel phantoms under multiple shielding configurations: aluminum shells with mass thicknesses of 5, 10, 20, and 30 g/cm², and a polyethylene shell with 30 g/cm². Simulations are performed using the GEANT4 Monte Carlo toolkit for all ions from Z = 1 to 28 over a kinetic energy range of 1 MeV/n to 100 GeV/n. Dose equivalents are computed using both the ICRP60 and NASA quality factors. Organ-specific dose coefficients and their energy dependence are presented, providing reference data for spacecraft shielding design. At solar maximum, when the GCR flux is at its minimum, the effective dose equivalent is reduced by up to 31% and 18% using the ICRP60 and NASA quality factors, respectively, for the thickest shielding considered.