Designing a boron nitride polyethylene composite for shielding neutrons

Abstract

Neutrons are encountered in many different fields, including condensed matter physics, space exploration, nuclear power, and healthcare. Neutrons interacting with a biological target produce secondary charged particles that are damaging to human health. The most effective way to shield neutrons is to slow them to thermal energies and then capture the thermalized neutrons. These factors lead us to consider potential materials solutions for neutron shields that maximize the protection of humans while minimizing the shield mass and adapt well to modern additive manufacturing techniques. Using hexagonal boron nitride (hBN) as a capture medium and high-density polyethylene (HDPE) as a thermalization medium, we aim to design the optimal internal structure of h10BN/HDPE composites by minimizing the effective dose, which is a measure of the estimated radiation damage exposure for a human. Through Monte Carlo simulations in Geant4, we find that the optimal structure reduces the effective dose up to a factor of 72 over aluminum (Al) and up to a factor of 4 over HDPE; this is a significant improvement in shielding effectiveness that could dramatically reduce the radiation exposure of occupational workers.

Fabrication of Thermally Conductive and Wear-Resistant UHMWPE-Based Composites for Nuclear Shielding Applications

“…Geant4 is often utilized for simulating the transport of particles in materials, and it finds extensive applications in high-energy physics and related fields. Geant4 can be used as a tool to evaluate the shielding performance of UHMWPE against γ rays and neutrons. , …”

“…The I / I 0 of the materials was then calculated. The μ and μ m were determined using the following formula: where, I is the penetration intensity, I 0 denotes the incident intensity, d is the thickness of samples, and ρ is the density of materials.…”

“…Geant4 can be used as a tool to evaluate the shielding performance of UHMWPE against γ rays and neutrons. 68,69 In this work, Geant4 was used to predicate the penetration capability, i.e., transmittance (I/I 0 ), linear attenuation coefficient (μ), and mass attenuation coefficient (μ m ) of neutrons through UHMWPE-based composites, thereby reflecting their neutron-shielding performance. The thickness of sample blocks was set at 2, 4, 6, 8, and 10 mm.…”