Novel metallic Bi-Pb–Cd-Ag alloys for shielding against neutrons and gamma rays

Abstract

Obtaining high-performance shielding alloys against mixed neutrons and γ-rays is vital in the field of nuclear radiation. In this work, shielding Bi-Pb–Cd-Ag alloys with superior thermal neutron shielding and high ability to attenuate γ-rays were developed. The microstructure, melting behavior, and mechanical properties of the prepared alloys were characterized. The γ-rays mass attenuation coefficients () were obtained using WinXCom program in the energy range of 0.015–15 MeV. The shielding parameters including atomic and electronic cross-sections (σ a and σ e), effective atomic number (Z eff ), effective electron density (N eff ) were calculated. The exposure buildup factor (EBF) using a geometric progression (GP) fitting method was estimated. The experimental measurements were carried out at 662 and 1173, 1332 keV of 137Cs and 60Co isotope sources, respectively using a scintillation gamma spectrometer NaI(Tl) detector. The calculated results of WinXCom are consistent and in agreement with the experimental values of The macroscopic effective removal cross-section () of the samples for fast neutrons were calculated. Also, the attenuation of thermal neutrons through the prepared alloys has been investigated. It was found that the alloy containing 30% Cd complies with the compromise between superior thermal neutron attenuation besides its superior ability to attenuate γ-rays with good mechanical strength and high ductility.