ABSTRACT
A new theoretical approach was used to calibrate and calculate the full-energy peak efficiency of the NaI (Tl) detectors based on the direct statistical method proposed by Selim and Abbas for cylindrical detectors. In addition, the self-attenuation of the source matrix, the attenuation by the source container and the detector housing materials were considered in the mathematical treatment. Results were compared with those measured by a cylindrical NaI (Tl) detector with resolution (FWHM) at 662 keV equal to 7.5 %. (152)Eu aqueous radioactive spherical sources covering the energy range from 121 to 1408 keV were used. In comparison, the calculated and the measured full-energy peak efficiency values were in good agreement.
Subject(s)
Radiometry/methods , Sodium Iodide/chemistry , Algorithms , Calibration , Equipment Design , Europium/analysis , Models, Theoretical , Photons , Radiation Monitoring/instrumentation , Radiation Monitoring/methods , Radiometry/instrumentation , Thallium/chemistryABSTRACT
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. (152)Eu aqueous radioactive sources covering the energy range from 121 to 1408 keV were used. Remarkable agreement between the measured and the calculated efficiencies was achieved with discrepancies less than 2%.
