New analytical approach to calibrate the co-axial HPGe detectors including correction for source matrix self-attenuation

Abstract

To calibrate the co-axial HPGe semiconductor detectors, we introduce a new theoretical approach based on the Direct Statistical method proposed by Selim and Abbas (1995, 1996) to calculate the full-energy peak efficiency for cylindrical detectors. The present method depends on the accurate analytical calculation of the average path length covered by the photon inside the detector active volume and the geometrical solid angle Ω, to obtain a simple formula for the efficiency. In addition, the self attenuation coefficient of the source matrix (with a radius greater than the detector's radius), the attenuation factors of the source container and the detector housing materials are also treated by calculating the average path length within these materials. 152Eu aqueous radioactive sources covering the energy range from 121 to 1408keV were used. Remarkable agreement between the measured and the calculated efficiencies was achieved with discrepancies less than 2%.