Determination of the Volume Efficiency of Hyper Pure Germanium (HPGe) Detector Using Ra- 226 Point Source

Abstract

In the present work, a previous mathematical method to determine the volume efficiency of Hyper Pure Germanium (HPGe) detector for cylindrical shape sources at different distances is introduced and the volume efficiency is calculated using the KCl method covering the energy range from 186 to 2614 keV. Correction factors F1 are suggested for KCl solution and F2 due to the presence of medium between the sample and the detector. To validate these results eighteen soil samples were collected from Ras Shakier, Egypt. The samples were filled in 100 ml polyethylene containers, weighed, sealed and stored for about one month in order to allow radioactive equilibrium to be reached (secular equilibrium). This step ensured that radon gas and its daughters remain in the samples. The samples were measured at different distances. The activities were determined using volume efficiency from the mathematical method and the KCl method using two Ra-226 point sources. Two samples were also measured in Environmental Pollution Lab at the Egyptian Atomic Energy Authority using the standard calibration source of U-238 RGU-1 and Th-232 RGTh-1. The specific activity results were compared with the mathematical method calculation to confirm the mathematical method.