journal of kerbala university

Abstract

In the present work the effect of the distance surroundings material on the signal to noise (S/N %) are studied , for the two sizes of scintillation detectors NaI (Tl); (3"X3" and 1.5"X1.5"),by using two radioactive sources (Co- 60 and Cs -137) and Iron and P.V.C cylinders. The experimental results shows that the Signal to the noise ratio (S/N %) are increasing in both the distance and photons energy increasing. The effect of size of NaI(Tl) on the ratio of (S/N %) as well as the type of materials dependence is present too.