Efficiency calibration curve analysis of gamma spectrometer by using ¹⁵²Eu standard source in energy range of 121 - 1408 keV

Accuracy in determining the relative activities of radioactive materials using High Purity Germanium (HPGe) detector gamma spectrometer system is highly dependent on the precision and accuracy of the efficiency calibration of the detector. The analysis of HPGe detector efficiency calibration curve, PTKMR - BATAN, at the energy range 121 - 1408 keV have been done. Efficiency calibration curve as a function of energy was made using standard sources of Europium-152, which have a nine-point energy peaks distributed evenly in the range of energy mentioned above. Efficiency calibration performed at a distance of 25 cm source to detector. The data of efficiency calibration curve, which made from years 2018 until 2019 are analyzed using ratio of the measured efficiency (ε) with calculated the efficiency of the calibration curve equation as a function of energy efficiency (εo). Ratio of measured and calculated efficiency values with a calibration equation efficiency, at Energies from 121 to 344 keV ranged from 0,88 to 1.12 and the energy of higher 400 keV the ratio ranged from 0.98 to 1.02. The results showed that the efficiency calibration curve of HPGe detector gamma spectrometer system has a accuracy of about 1 % in the region from 121 to 344 keV and in the energy region above 400 keV the accuracy was 0,2 %. (author)