Design and evaluation of eco-engineered B4C/Fly ash composites: A green material for gamma and neutron shielding applications

Abstract

In this study, eco-engineered composite pellets made of fly ash and boron carbide (B₄C) are designed and evaluated for use in gamma-ray and neutron shielding applications.  Composite samples with different B₄C ratios (0–75 wt%) have been created and examined using both theoretical and experimental methods.  XRD and SEM are used for structural and morphological characterizations.  A NaI(Tl) detector is used to measure gamma-ray attenuation parameters such as LAC, MAC, HVL, TVL, MFP, Z_eff, and buildup factors. These values are further evaluated using Phy-X/PSD and GAMOS simulations. Values for the fast neutron removal cross-section (FNRCS) are also calculated.  The composite with the most balanced performance is BCFA25, which has a compact microstructure and improved attenuation efficiency.  Increasing the content of boron and carbon with lower atomic numbers increased neutron shielding but decreased Z_eff and electron density. Strong agreement is found between theoretical models and experimental outcomes.  The results indicate that B₄C/fly ash composites, especially BCFA25, offer a lead-free and sustainable option for radiation shielding in industrial, nuclear, and medical applications.