Measurement of shielding effectiveness of building blocks against 662 KeV photons

Abstract

This study uses building blocks as a shield for gamma energy source of 662 KeV from Cs-137. The attenuation from the block is compared with those obtained when conventional shields like iron, lead and concrete are used as shield for Cs-137. This was done with the aim of finding out the level of shielding and the thickness of building block needed to confer same level of shielding as the already mentioned conventional shields. The results obtained using a gamma spectrometer with a NaI(Tl) detector showed that the Half Value Thickness (HVT) of building block, concrete, iron and lead were 5.1420 cm, 3.8043 cm, 1.1908 cm, and 0.5581 cm respectively. With the results from this work, a shield of 37 cm building block (though bulky in size) will attenuate the source and can be used as a substitute for lead which would require a 4.4 cm thickness.