عنوان مقاله [English]
نویسندگان [English]چکیده [English]
A useful benchmark for the reliability of gamma spectrometry results is to provide measurement uncertainty. Due to the importance and necessity of radiation monitoring in water resources, this research has been oriented toward providing measurements of the gamma- emitting radionuclides along with introducing the expression for the uncertainty that appeared in these measurements. To calculate the uncertainty of the activity measurements in water, a sample, where its radioactive elements were obtained from the PolAtom Company, was used. The calculations were performed based on the 661 keV peak of 137Cs radionuclide and a high-purity germanium detector (HPGe). The investigations show that the factors affecting the measurement uncertainty are composed of two parts, including counting with the gamma spectroscopy system and sample preparation, where each of these parts comes from several sources of uncertainty such as uncertainties associated with the counting process, efficiency calibration, emission probability, the counting correction factors, and the mass measurement. The results of analyses show that the relative uncertainty is about 3.7% (Coverage factor = 1) for a water sample with an activity of 425 Becquerel from 137Cs.
1. Clarke, Roger. Control of low-level radiation exposure: time for a change?. Journal of Radiological Protection, 19 (2), 107 (1999).
2. United Nations. Scientific Committee on the Effects of Atomic Radiation. Report of the United Nations Scientific Committee on the Effects of Atomic Radiation: Fifty-sixth Session (10-18 July 2008). No. 46. United Nations Publications, (2008).
3. E.O. Agbalagba, R.A. Onoja, Evaluation of natural radioactivity in soil, sediment and water samples of Niger Delta (Biseni) flood plain lakes, Nigeria, Journal of Environmental Radioactivity, 102 (7), 667-671 (2011).
4. ISO 13164-4: 2015, Water quality- Radon-222-Part 4: Test method using two-phase liquid scintillation counting.
5. Merril Eisenbud, Thomas Gesel, Environmental radioactivity. Fourth Edition. Academic press (1997).
6. Z. Pourhabib, A. Binesh, S.A. Mohammadi Study on heavy radioactive pollution: Radon and Radium in streams and drinking water of Ramsar region by measured Prassi system, IJPR, 11 (4), 397-403 (2012).
7. Gilmore, Gordon. Practical gamma-ray spectroscopy, John Wiley & Sons, (2011).
8. International Vocabulary of Metrology- Basicand General Concepts and Associated Terms (VIM), JCGM (2000).
9. C. Bell, A Beginner’s Guide to Uncertainty of Measurement, Issue 2, HMSO, London, UK (2001).
10. Jodłowski, Paweł, Stefan J. Kalita, Gamma-ray spectrometry laboratory for high-precision measurements of radionuclide concentrations in environmental samples, Nukleonika, 55, 143-148 (2010).
11. H. Ramebäck, P. Lindgren, Uncertainty evaluation in gamma spectrometric measurements: Uncertainty propagation versus Monte Carlo simulation, Applied Radiation and Isotopes, 142, 71-76 (2018).
12. Xhixha, Gerti, Matteo Alberi, Marica Baldoncini, Kozeta Bode, Elida Bylyku, Florinda Cfarku, Ivan Callegari et al. Calibration of HPGe detectors using certified reference materials of natural origin, Journal of Radioanalytical and Nuclear Chemistry, 307 (2), 1507-1517 (2016).
13. Plukis, Artūras, Vytenis Barkauskas, Rūta Druteikienė, Grigorijus Duškesas, Darius Germanas, Arūnas Gudelis, Laurynas Juodis, Elena Lagzdina, Rita Plukienė, and Vidmantas Remeikis, Uncertainty of determination of 158Tb in the RBMK nuclear reactor waste, Applied Radiation and Isotopes, 134, 190-193 (2018).
14 IAEA, 2004a. Quantyfing uncertainty in nuclear analytical measurements, TECDOC 1401:2004. International Atomic Energy Agency, Vienna, Austria.
15. Firestone, Richard B., Virginia S. Shirley, Table of isotopes, 2 volume set, Table of Isotopes, 2 Volume Set, by Richard B. Firestone, Virginia S. Shirley (Editor), pp. 3168. ISBN 0-471-33056-6. Wiley-VCH, December 1998. (1998): 3168.
16. ISO/IEC Guide 98-3, Uncertainty of measurement-Part 3: Guide to the expression of uncertainty in measurement (GUM:1995).