An extensive study of depth dose distribution and projectile fragmentation cross-section for shielding materials...

Geant4 Monte Carlo simulation was executed for ¹⁶O beam in various elemental and hydrogenous materials for assessment of ion characteristics and shielding efficacy. In the energy-dependent comparison, at energies 200-594 MeV/n, the peak to entrance ratio decrement up to 78.6% in water target validates the substantial increase in fragmentation factor. Further, hydrogenous materials and low Z elements (C, Al) demonstrate a low peak-to-entrance ratio (0.92-1.66) compared to heavy element (Cu, Sn, Pb) ratio (2.73-3.54), at 594 MeV/n, indicating the high fragmentation properties of hydrogenous and low Z elements. Accordingly, the depth dose reduction percentage was found to be significantly higher for hydrogenous materials (0.92-1.72%) having 4.20-14.37 H wt.% than non-hydrogenous targets (0.09-0.82%). LiH was found to exhibit the lowest peak-to-entrance ratio and highest depth dose reduction. The high shielding effectiveness of LiH (12.59%) irrespective of having a low H fraction compared to polyethylene (14.37%) which is widely used shielding material, suggests the contribution of low Z element Li (87.41 wt%) over the C (85.63 wt%) element in the material. Also, simulated results of fragmentation for high Z materials were compared with the experimental data for the reliability of Geant4. Finally, the comparison of these properties recommends the use of hydrogenous materials with low Z elements for effective space radiation shielding.