Radiation Attenuation Properties of High-Density Polyethylene

Abstract

We present a systematic Geant4 Monte Carlo investigation of neutron transport and attenuation in high-density polyethylene (HDPE, ρ = 0.961 g/cm³) over energies from 25 meV to 14 MeV and slab thicknesses from 2 to 50 cm. Using the QGSP_BIC_HP physics list with the ENDF/B-VIII.0 evaluated nuclear data library, we extract macroscopic attenuation coefficients, half-value layers (HVL), and tenth-value layers (TVL) from exponential fits to the Monte Carlo transmission data, and validate them against reference cross-section data. Spectral hardening of a ²³⁵U Watt fission source is quantified, and HDPE performance is benchmarked against water, paraffin, and ordinary concrete. For 1 MeV neutrons, we obtain μ = 0.475 ± 0.002 cm⁻¹, HVL = 1.46 cm, and TVL = 4.84 cm, confirming HDPE as one of the most effective compact solid neutron shields across the energy range studied.