Gamma-ray spectrometry is a very powerful tool for radioactivity measurements. The gamma-ray spectrometer laboratory in Centre for Energy Research and Training (CERT), Ahmadu Bello University, Zaria, Nigeria is accredited to perform measurements of radioactive content of samples collected from the environment, food chain or industrial products with the aid high resolution HPGe detector. For accurate gamma-ray spectrometry, certain measurements were considered; the efficiency of the detector was performed experimentally against energies within the range of 59.50 keV (241Am) to 2204.50 keV (226Ra) for the respective geometries of 1 – 6 cm. The sustained solid angle relations with respect to the inverse square of sample geometries from 1 – 6 cm were evaluated. Another main point of this work was focused on the efficiency at geometry of 5 cm with respect to the three selected energies: 661.60 keV (137Cs), 1173.2 keV (60Co) and 1332 keV (60Co) for the main axis, ten degree off main axis, forty five degree off main axis and ninety degree off the detector main axis. In order to verify optimum geometries in our laboratory for both short lived and long lived radionuclides analyses, the evaluation of efficiencies for the respective energies: 1173.2 keV (60Co), 1332.5 keV (60Co), 1764 keV (226Ra) and 2294 keV (226Ra) were plotted against geometries of 1 to 6 cm from the detector end cap along the main axis.
Cite this paper
Njinga, R. and Jonah, S. (2015) Calibration of the High Purity Germanium Gamma-Ray Spectrometer in Cert, Abu Zaria, Nigeria. Modern Instrumentation, 4, 11-17. doi: 10.4236/mi.2015.42002.
|||Blaauw, M. (1993) The Use of Sources Emitting Coincident γ-Rays for Determination of Absolute Efficiency Curves of Highly Efficient Ge Detectors. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 332, 493-500.
|||Cincu, E. (1992) A Practical Method for Accurate Measurement of Radionuclide Activities in Environmental Samples. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 312, 226-230.
|||Boshkova, T. (2003) Effective Thickness of Bulk Samples in “Close” Measuring Gamma-Ray Spectrometry. Applied Radiation and Isotopes, 59, 1-4.
|||Abbas, M.I., Nafee, S. and Selim, Y.S. (2006) Calibration of Cylindrical Detectors Using a Simplified Theoretical Approach. Applied Radiation and Isotopes, 64, 1057-1064.
|||Singh, C., Singh, T., Kumar, A. and Mudahar, G.S. (2004) Energy and Chemical Composition Dependence of Mass Attenuation Coefficient of Building Materials. Annals of Nuclear Energy, 31, 1199-1205.
|||Saegusa, J., Kawasaki, K., Mihara, A., Ito, M. and Yoshida, M. (2004) Determination of Detection Efficiency Curves of HPGe Detectors on Radioactivity Measurement of Volume Samples. Applied Radiation and Isotopes, 61, 1383-1390.
|||Debertin, K., Schotzig, U., Walz, K.F. and Wein, H.M. (1976) Efficiency Calibration of Semiconductor Spectrometers —Techniques and Accuracies. Proceedings of ERDA Symposium on X- and Gamma-Ray Sources and Applications, Ann Arbor, 59-62.|
|||Ewa, I.O.B., Bodizs, D., Czifrus, S., Balla, M. and Molnar, Z. (2002) Germanium Detector Efficiency for a Marinelli Beaker Source-Goemetry Using the Monte Carlo Method. Journal of Trace and Microprobe Techniques, 20, 161-170.|
|||Ahmed, Y.A. (2013) Parameter Measurement, Efficiency Calibration and Quality Assurance for a Vertical GEM- 30195 Coaxial HPGe Detector. Nigerian Journal of Physics, 24, 1-15.|
|||San Miguela, E.G., Perez-Morenoa, J.P., Bolivara, J.P. and Garcia-Tenoriob, R. (2004) A Semi-Empirical Approach for Determination of Low-Energy Gamma-Emmiters in Sediment Samples with Coaxial Ge-Detectors. Applied Radiation and Isotopes, 61, 361-366.
|||Njinga, R.L., Alfa, B. and Ewa, I.O.B. (2009) Geometry Scaling Using HPGe Detector (Model 811-10195) Applied in Neutron Activation Analysis (NAA) Measurements with Nigeria Research Reactor-1 (NIRR-1). African Journal of Natural Science, 12, 67-73.|
|||Owens, A. (1989) A Comparison of Empirical and Semi Empirical Efficiency Calculations for Ge Detectors. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 274, 297- 304.|
|||Gurriaran, R., Barker, E., Bouisset, P., Cagnat, X. and Ferguson, C. (2004) Calibration of a very large ultra-low background well-type Ge detector for envoironmental sample measurements in an underground laboratory. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 524, 264-272.
|||Vargas, M. J., Fernández Timón, A., Cornejo Diaz, N. and Pérez Sánchez, D. (2002) Monte Carlo Simulation of the Self-Absorption Correction for Natural Samples in Gamma-Ray Spectrometry. Applied Radiation and Isotopes, 57, 893-898.
|||Quindós, L.S., Sainz, C., Fuente, I., Nicolás, J., Quindós, L. and Arteche, J. (2006) Correction by Self-Attenuation in Gamma-Ray Spectrometry for Environmental Samples. Journal of Radioanalytical and Nuclear Chemistry, 270, 339- 343.|
|||Njinga, R.L., Ewa, I.O.B., Jonah, S.A., Baba, A., Ahmed, Y.A., Agbo, G.A., Ebobenow, J. and Nasiru, R. (2011) Alternative Approach for Efficiency Data Generation in Neutron Activation Analysis. International Journal of Applied Science and Technology, 1, 244-256.|
|||Erdtmann, G. and Soyka, W. (1979) The Gamma-Rays of the Radionuclides: Tables for Applied Gamma-Ray Spectrometry (Vol. 7). VerlagChemie: Weinheim, New York, 1-236.|
|||Kamboj, S. and Kahn, B. (1994) Intrinsic Efficiency Calibration of a Large Germanium Detector. Radioactivity and Radiochemistry, 5, 46-56.|