REDUCING THE EFFECT OF BACKSCATTERING AND COMPTON EDGE ON NA-22'S SPECTRUM USING DIFFERENT MATERIALS

Abstract

The purpose of this study is the effect of shields made of different materials on reducing back scattering and the Compton edge are calculated at the photon energies (511 ,1274 ) Kev emitted by a source (Na-22). Different types of shields such as (stander, lead3cm, lead 2cm, polyethylene and concrete) were studied using one of gamma-ray spectroscopy techniques, which consists of a thallium NaI (Tl)–activated sodium iodide scintillation detector with dimensions of  3"×3" and its electronic accessories and by using radioactive source (Na-22). The results we obtained indicated a decrease in the overall count rates when lead shield surrounds the detector, as the count rates decreased in all channels (almost all the energy peaks of the spectrum). Increasing the thickness of the lead shield will prevent more gamma rays from reaching the detector. This traditional method of detector shielding, consisting of a single material, is considered the best method for detector shielding. The results we obtained in the experimental part confirmed the theoretical part.