Determination of performance specifications of gamma spectrometry systems in Universiti Teknologi Malaysia

Abstract

High purity germanium (HPGe) detector received a research attention in radiation measurement area. It is the most distinguished radiation measurement instrument and have excellent energy resolution. Their demands are kept on increasing with modernization in industries. Typically, good working performance of the system is totally depending on warranted specifications offered by its manufacturer. This study aims to determine the working condition and compare the performances of two gamma-ray spectrometry (GS1 and GS2) in nuclear laboratory, UTM. The GS1 consist of n-type closed end coaxial HPGe detector and GS2 consist of p-type closed end coaxial HPGe detector. The specification such as resolution, peak-to-Compton ratio, peak shapes and relative efficiency are measured using American National Standard Institute and Institute for Electrical and Electronic Engineers ANSI/IEEE 325-1996 standard procedure in order to have the same meaning with the manufacturers. Perfect Gaussian peaks, counting efficiency and time measurement were also determined. The result obtained from the specification test, shows the measured values fall within the recommended limit. GS1 found to have high resolution 1.9 keV as compared with GS2 with 1.69 keV, while GS2 shows higher counting efficiency detection and peak-to-Compton ratio. Also, the skew factor checked in both GS1 and GS2 is found to be 1.0 which presented well defined Gaussian peaks. Dead time effect found to be decreased with the increased in gamma-ray energy in both detectors. It concluded that based on the results, the performance of the two coaxial HPGe detectors in nuclear laboratories UTM are in good working condition. The significance of this study is to ensure that the detectors are keep control and monitoring for future use. This will improve the efficacy potential performance of these two gamma ray spectrometry systems.