Quality optimization of neutron and gamma concrete shields doped with galena, hematite and limonite for Am-Be neutron source and 137Cs and 60Co gamma sources using experimental method and Monte Carlo simulation

Abstract

This study aims to find the optimal combination ratio for different minerals in the concrete radiation shield structure. In this study, we defined the quality factor (QF) of concrete radiation shielding through experimental methods and Monte Carlo simulations. This quality factor is calculated as the product of the linear attenuation coefficients for neutron radiation (µ_n) and gamma radiation (µ_γ), along with the compressive strength of the concrete. We compared these values for samples of galena, limonite and hematite. So far, much research has been conducted in this field; in other past research, a few numbers of samples with different compositions have been examined. However, in this study, different concentrations of the mentioned minerals were examined and a graph of various parameters was drawn, which provides researchers with comprehensive data for the mixing ratio of different materials in the construction of concrete shields. The Am-Be neutron source and the ¹³⁷Cs and ⁶⁰Co gamma sources were considered as laboratory and simulation sources. According to the results, by increasing the concentration of minerals in concrete, its µ_γ increases. And by increasing the concentration of these minerals up to a certain value, its ability to attenuation the neutron beam is strengthened. Due to the presence of hydrogen atoms in the limonite structure, with the increase in the concentration of this mineral in the concrete shield, its µ_n always increases. But in galena and hematite shields, after the certain concentration of these minerals, not only their neutron attenuation ability is no longer increased, but also even decreases for galena samples. The sample G₄₀ has the highest QF. To optimizing the weight of the shield, the comparison of QF/ρ values has been done and the results show that samples H₄₀, H₅₀, H₆₀, G₃₀, G₄₀ and L₃₀ have best QF/ρ value and they are suitable options to make the concrete radiation shield for various nuclear centers.