Studying the effect of polymers doped with different concentration of nano lead on Build up factor for gamma rays emitted from Co-60

Abstract

- In this research, we have studied the shielding properties against gamma ray with energies (1.172MeV and 1.332MeV) emitted from the radioactive source (Co-60) with radiation activity 95mCi. These composite shields made of polymethyl methacrylate (PMMA), anthracene supported by nano lead. The emitted rays are detected by NaI(Tl) detector. The buildup factor were calculated as a function of the lead concentration in shields in range (0.5,2,5,7,10%), and as well as buildup factor are calculated for shielding thickness of shields (PMMA) that supported by a concentration of (25%) of nano lead powder in the range of      (1,1.5,2,2.5,3)cm. The results show a decrease in buildup factor with increasing the concentration, while their values increase with increasing the thickness of shielding matterials in a certain concentration, also the results show that the Buildup factor was higher in low-energies from their in high-energies, Study of the buildup factor for all shields samples with concentration (10%) show that the buildup factor value is greater in a pure polymethyl methacrylate (PMMA) and pure anthracene (without any substance addition), and lower buildup factor value in polymethyl methacrylate (PMMA), anthracene  with concentration (10%)  supported by nano-lead.