Measuring the HPGE detector efficiency at different densities using Radiation Point Sources and applying the equivalent volume method
Z. Eadan*, N.A. AL-Sowaidi
National Atomic Energy Commission of Yemen (NATEC), Sana’a, Yemen
This research presents a new method for measuring the absolute efficiency of High Purity Germanium (HPGe) detector at different densities using point sources: 241Am, 137Cs, and 226Ra, where good results have been achieved similar to those obtained by using the reference sample spiked with the standard reference solution (R8/31/38QCY48) for a geometric volume of 200 ml.
At this method, the above mentioned point sources and a soil sample similar in density (1.6 gm/ml) to the reference sample were used, and the absolute efficiency of HPGe detector was measured using a volumetric quantity of the soil sample that achieves efficiency values similar to the already known calibrated efficiency for energies in the range of 59.54 KeV to 2204 KeV. Therefore, it is found that the equivalent volume for low energy (59.54 KeV) is about 61 ml and for others energies (≥185 KeV) it is 120 ml. The equivalent volumes have been applied on known chemical materials with various densities ranging from 0.67 to 1.35 gm/ml in order to measure the absolute efficiency and creating calibration curves without need to reference samples. Furthermore, the resultants of linear correlation relations between density and efficiency were used to calculate efficiency for any energy and at any density with a relative error less than 11%.
Keywords: HPGe Detector, Density, Efficiency, Attenuation, Equivalent Volume, Point Sources.1-01072022-40-47 SJ of NATEC