RESUMO
The mass attenuation coefficient of lead nitrate (Pb(NO3)2)-filled polycarbonate (PC) composite films were determined both computationally (using Baltakmen's and Thummel empirical formulae) and experimentally using 204Tl and 90Sr-90Y radio-isotopes for films at different filler levels 0, 5, 15, 25, 35 and 50 weight percent (Wt.%). In comparison with Thummel empirical formula, the values obtained from Baltakmen's empirical formula is in good agreement with the experiment. The percentage decrease of half value layer values were (52 ± 8) and (60 ± 10)% for 204Tl and 90Sr-90Y, on comparing the values for 0 and 50 Wt.% films, and so the prepared composite films shield the beta particles effectively. The PC that used to shield the low-energy beta particles of 90Sr-90Y can also moderate the higher energy beta particles; the plot of end point energy of 90Sr-90Y versus thickness of PC exhibits a decreasing trend, which confirms that PC acts as an electron moderator.