Study of structural, physical, characteristics and radiation shielding parameters of Bi50-Pb40-Sn10 and Bi40-Pb40-Sn10-Cd10 alloys used for radiation therapy

Abstract

This work is carried out for the development of radiation shielding block alloys (bismuth based) for radiation therapy. Two different bismuth alloys whose composition, first, Bi-40 wt.% Pb-20 wt.% Sn and secondly, Bi-40 wt.% Pb-10 wt.% Sn-10 wt.% Cd are known as low melting temperature alloys (named fusible alloys). These alloys are used for the protection of vital critical organs inside the radiated area during radiotherapy applications. Structure, mechanical properties, and radiation shielding parameters of prepared alloys by conventional and rapid quench from molten state using the melt-spun technique have been studied and analyzed. It is concluded that from x-ray diffraction analysis, the presence of a new metastable crystalline phase (hexagonal structure a = 3.505, b = 3.505 and c = 5.795 nm) called Pb7Bi3 is detected. The formation of a metastable crystalline phase Pb7Bi3 causes the enhancement of mechanical properties. It is also concluded that the bismuth alloy which is cadmium-free exhibits superior microhardness compared to bismuth alloy containing cadmium. The measurements of radiation parameters were taken using 60Co and 6 MV. X-ray shows that alloy-free Cd has good attenuation coefficient, good mechanical characteristics, Vickers microhardness and moderate melting temperature. We can easily synthesise the bismuth alloy cadmium-free into suitable shapes in addition to it being friendly to the environment (green environment), so that they may be used as a substitute candidate instead of bismuth alloy containing Cd to use in radiation therapy.