Replacement of Lead by Green Tungsten-Brass Composites as a Radiation Shielding Material

Abstract

Lead metal proved to be toxic. Its lethal effect became eminent. Many developed countries have banned lead usage in various applications. Seeking alternative material to replace lead is a crucial goal. As density concerns, tungsten-brass composite is a good candidate for lead replacement. In this study the radiation shielding effects of tungsten-brass composites were evaluated. To attain this goal, four tungsten-brass sets were prepared. The tungsten (W) wt. % in these specimens was ranged from 50 to 80, the balance is brass. The specimens were sintered at 10500C in alumina tube furnace under protective environment. To evaluate the radiation shielding performance of these specimens, two gamma ray sources, 137Cs and 60Co were utilized. The photon energy levels for these sources were of o.662MeV and 1.25MeV respectively. The measurements were performed using gamma spectrometer contains NaI (Tl) detector. The anti-radiation performance of the tungsten-brass was correlated to that of lead under similar conditions. Vickers micro hardness, relative sintered density, micro structural characterisation and linear attenuation coefficient (μ) were carried out. Samples with the highest Weight percentage of W has the highest hardness value while the one with the lowest Weight percentage of W. The linear attenuation coefficients of the specimens were significantly improved by increasing the W wt. % of the specimen. The linear attenuation coefficients of the tested specimens ranged from 0.85±0.010cm-1 to 1.12±0.049cm-1for 60Co and0.73±0.012 cm-1 to 0.97±0.027 cm-1 for 137Cs. This result indicates that W-brass composites are suitable material for lead replacement as a shielding barrier.Keywords: Attenuation coefficient, radiation shielding, lead, tungsten-brass composites, NaI (Tl).