The effect of heavy metals on the radiation shielding capabilities of borated polyethylene: A Geant4 study

Abstract Research has increasingly focused on polymers for medical applications due to their beneficial properties. Polyethylene, a common polymer, is extensively used as a neutron shield in radiation-related environments, particularly in hospitals. Recently, borated polyethylene—created by combining polyethylene with 5% boron by weight—has been employed in hospital doors due to its exceptional durability across a wide temperature range and its effective neutron shielding capabilities. Hospital doors must protect against radiation leakage that could endanger patients and staff while also being lightweight, resistant to moisture and chemicals, sound-absorbent, and flexible during manufacturing. Borated polyethylene meets all these criteria, leading many manufacturers to produce hospital doors from borated high-density polyethylene (BHDPE). In this study, the shielding effectiveness of borated polyethylene, enhanced with 5% of heavy metals such as iron, bismuth, and tungsten, was theoretically analyzed using Geant4 against photons and neutrons with energies ranging from 10 keV to 20 MeV. The results indicated that iron-borated high-density polyethylene (Fe-BHDPE) offers the best neutron shielding, followed by tungsten-borated high-density polyethylene (W-BHDPE) and bismuth-borated high-density polyethylene (Bi-HDPE). For photon shielding, Bi-HDPE performed the best. The choice of metal and its proportion in radiation protection doors should be tailored to the specific type of radiation present in the facility, considering potential interactions, surrounding conditions, scattering effects, and any secondary particles that may be produced.