Test performance of Gamma Spectrometry Co-Axial High Purity Germanium detectorsin Universiti Teknologi Malaysia

Abstract

The utilization and prolonged working of two gamma spectrometry (GS1 and GS2) in nuclear laboratories, UTM, causing one to questioning its performance. To achievethe higher quality outcomes of gamma spectrometry system. Itsperformance specifications should verify against the warranted values offered by the manufacturer. High purity germanium (HPGe) detectors is the most distinguished radiation measurement instrument that produced excellent energy resolution. The aims of this studyis to determine the working condition and compare the performances of two gamma spectrometry systems. The GS1 consist of n-type closed end coaxial HPGe detector GC 2018 model and GS2 consist of p-type closed end coaxial HPGe detector of GEM25-76-LB-C model. The test performance specifications such as resolution, peak shapes, peak-to-Compton ratio, figure of merit, and dead time for both spectrometry systems are measured using American ANSI/IEEE 325-1996 standard procedure.Four (4) standard source 60Co, 152Eu, 133Ba, and 137Cs were used. It covered energies range from (4.3 keV-3194.9) keV. The source-to-detector distance is set 25 cm to avoid the summing coincident gamma ray. The relative efficiency measured improve by 0.2% and 4% for GS1 and GS2 respectively. Peak-to-Compton ratio of both detectors improved by factor of 4.Dead time found to be less than 1% at 25 cm compared to 12 cm. From the results, GS1 has higher resolution compared to GS2 detector. Based on the results obtained, it can be concluded that the performance of two coaxial HPGe detectors in nuclear laboratories, (UTM) are in good working condition.Thisrevealed propercontrol and maintenance of the two detectors.