Contents lists available at ScienceDirect Radiation Physics and Chemistry journal homepage: www.elsevier.com/locate/radphyschem On the physical, chemical, and neutron shielding properties of polyethylene/boron carbide composites Zaheer Uddin a , Tariq Yasin b , Muhammad Shafq b, ⁎ , Asif Raza c , Awais Zahur d a Department of Metallurgy and Materials Engineering, Pakistan Institute of Engineering & Applied Sciences, Nilore, Islamabad, 45650, Pakistan b Department of Chemistry, Pakistan Institute of Engineering & Applied Sciences, Nilore, Islamabad, 45650, Pakistan c Department of Chemical Engineering, Pakistan Institute of Engineering & Applied Sciences, Nilore, Islamabad, 45650, Pakistan d Department of Nuclear Engineering, Pakistan Institute of Engineering & Applied Sciences, Nilore, Islamabad, 45650, Pakistan ARTICLEINFO Keywords: Neutron shielding Polymer composite Boron carbide Fast neutrons Monte Carlo simulation Borated polyethylene ABSTRACT Monte Carlo methods are used for solving difcult stochastic problems in radiation shielding applications. The aim of this paper is to show the possibility of using the Monte Carlo code (MCBEND®) for evaluation and optimization of polyethylene with high boron loadings (for up to 40%) to reach better neutron shielding against fast neutrons (Am-Be neutron source). Boron is incorporated in polyethylene as boron carbide (B 4 C). MCBEND® (Monte Carlo code developed by ANSWERS) is used to simulate neutron transport through the developed bo- rated polyethylene composites. In order to verify the computer simulations, neutron detection and data acqui- sition systems have been assembled, modifed, and thoroughly tested for shielding efciency. It is shown that borated composite with 10% of boron content showed the highest experimental mass removal cross section. Moreover, composite formulation with 10% of boron shows optimum density, morphology, mechanical attri- butes, and thermal stability than that of the neat polyethylene matrix. A comparison of experimental and si- mulation mass removal cross sections shows that the geometry and physics models proposed in this work are in close agreement, with maximum relative diference of not more than 15%. 1. Introduction Modern world fnds extensive utilization of radiations, radio- isotopes, and energy-related materials in power generation, medicine, and aerospace sectors. Neutrons are an important class of nuclear ra- diations, which do not possess net electric charge; therefore they cannot be stopped by electric forces. Neutron shielding is based on the prin- ciple of attenuation, which is an ability to mitigate the radiation efects by blocking or bouncing through a barrier material. Neutrons can be rendered less harmful through elastic and inelastic scattering (John and Lamarsh, 1955; Martin, 2013; Murray, 2014). Fast reactors typically involve high energy neutrons that must be shielded for efcient op- eration. Since fast reactors do not require moderation, shield design must include materials containing high hydrogen content to ensure thermalization followed by the absorption of fast neutrons. Hydrogen and hydrogen-based materials are preferred for moderating fast neu- trons most probably by forming cross-sections that may interact with these neutrons. Compounds with a higher content of hydrogen, such as polyethylene (PE), parafn wax (PW), and water form efcient neutron barriers. Moreover, neutron shielding properties may be further im- proved by incorporating boron salts (Abd and Elkady, 2014; Groves, 2017; Uhlář et al., 2013). Monte Carlo methods physically simulate the fate of individual particle (neutron) and help predict detailed radiation level in a geo- metrical system. The possible outcome is some form of radiation dose, radiation damage, or an instrumental response to a particular radiation. These simulations fnd diverse applications in reactor operation, nu- clear fuel management, incident detection systems, and personal dose uptake. With advances in the feld of composites, new materials are being developed, evaluated, and applied for radiation shielding appli- cations (Geof et al., 2017; Kyrieleis, 2014). Polymer composites have been widely used for radiation shielding applications because of their light weight, easy process-ability, and chemical inertness. Moreover, these materials can be easily in- corporated with boron containing salts to further infuence radiation shielding phenomenon. Consequently, borated polymer composites possessed good physico-mechanical properties than that of their neat counterparts and many researchers have investigated the use of such https://doi.org/10.1016/j.radphyschem.2019.108450 Received 1 November 2018; Received in revised form 18 July 2019; Accepted 11 August 2019 Abbreviations: Boron carbide, B 4 C; Am-Be, Americium–Beryllium ⁎ Corresponding author. E-mail address: shafq@pieas.edu.pk (M. Shafq). Radiation Physics and Chemistry 166 (2020) 108450 Available online 13 August 2019 0969-806X/ © 2019 Elsevier Ltd. All rights reserved. T