Authors: Ari M. Hamad & Hiwa M. Qadr
Abstract: This paper focuses on two main parts. Firstly, some of the general properties of gamma radiations were studied, along with the performance characteristic of a sodium iodide NaI(Ti) scintillation detection system. Gamma ray spectra were generated for Cesium-137 and Cobalt-60 sources, illustrating the interaction mechanisms which result in partial or complete deposition of incident gamma radiation energy in the NaI(Ti) detector. The energy response of the system indicated to be linear function of deposition energy and the resolution ranged between 8.12% – 6.29% for voltages 500 – 750 volts. The values of intrinsic total, intrinsic peak and absolute efficiency were calculated and indicated to fall as a function of gamma-ray energy. The intrinsic efficiency values ranged between 11.1 ± 0.004 – 4.2 ± 0.006% for energies of 511 – 1330 keV. Secondly, the attenuation of gamma radiations was investigated, two materials such as zirconium and tungsten were tested and their attenuation coefficient was calculated to find that which of them has higher attenuation coefficient. The zirconium attenuation coefficient is 0.42 ± 0.013 cm-1, whereas the tungsten attenuation coefficient is 1.6 ± 0.006 cm -1. These results of this experiment suggest that tungsten is better shielding material than zirconium. This is expected because of the greater density and higher atomic number of tungsten, therefore, tungsten can attenuate gamma-ray more than zirconium.
Keywords: General Properties of Gamma Radiation, The Attenuation 0of Gamma Radiation, Sodium Iodide Nal (Ti), Linear Attenuation Coefficient
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