Development of New Lead-Free Composite Materials as Potential Radiation Shields.

Mansour Almurayshid,Yousif Alssalim,Rashed Almsalam,Fahad Almasoud,Farouk Aksouh,Meshari ALQahtani,M. I. Sayyed

doi:10.3390/ma14174957

Abstract

Utilizing a polymer-based radiation shield offers lightweight, low cost, non-toxic compared to lead and solution for eliminating generated secondary neutrons. Incorporating silicon (i.e., one of the most abundant elements) in new applications, such as shielding, would have an impact on the economy and industry. In this study, seven potential shielding materials, composed of silicon, silicon carbide, and boron carbide embedded ethylene vinyl acetate (EVA) copolymers, are proposed. The shielding performance of these composite materials, including the attenuation coefficients (µ), the mass attenuation coefficients (µm), the half value layer (HVL), the mean free path (MFP), and the radiation protection efficiency (RPE) were examined using photon beams. Measured µm were verified against the calculated values. The averaged agreement was within ±7.4% between the experimental measurements and the theoretical calculation results. The HVL and MFP measured values for the polymer composites were lower than that for the pure EVA polymer, indicating the fillers in the polymers enhanced the shielding performance. The EVA + SiC (30%) and EVA + Si (15%) + B4C (15%) composites required the lowest thickness to stop 50% of the incident photons. The evaluation of experimental results of the RPE revealed that the polymer composites containing SiC (30%), Si (15%) + B4C (15%), or SiC (15%) + B4C (15%) succeeded in blocking 90–91% of X-rays at nearly 80 keV. However, a thicker shield of the proposed composite materials or combined layers with other high-Z materials could be used for higher energies.

Highlights

Controlling the vast usage of radiation in different daily applications is essential to avoid any harmful effects [1]
Solving Equation (1) as a function of I, Io and x allows the corresponding μ to be empirically determined for the proposed shielding polymer composites
The aim of this study was to investigate the attenuation efficiency of different potential lightweight shielding materials based on a 70% ethylene vinyl acetate (EVA) polymer content for X-rays

Summary

Introduction

Controlling the vast usage of radiation in different daily applications is essential to avoid any harmful effects [1]. As an alternative to metals, concrete is often used in the construction of large-volume shields, due to its good availability and low cost [3,4]. Low-Z elements or materials are the most active moderators, such as polymers considered as hydrogen-containing materials. One of most commonly available polymers is high-density polyethylene (HDPE), which is used in numerous applications. Another polymer that can be used as a moderator is ethylene vinyl acetate (EVA), which offers flexibly, a low manufacturing cost, and toughness [7]. In order to generate a radiation shielding material suitable for gamma radiation and neutrons, researchers have attempted to prepare polymer-based composites mixed with elements or materials and examine and characterize their radiation attenuation ability. The 15% filler concentration in HDPE had a higher shielding efficiency than that for 5% and 10%

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Methods

Conclusion