Abstract
An optimized k0-standardized neutron activation analysis method incorporating cyclic irradiations (k0-CNAA) for short-lived radionuclides (SLRNs) has been developed at the Dalat research reactor. This paper highlights precise reactor parameter characterization using a cyclic irradiation system, simple sample preparation, and advanced calibration of HPGe detector-based gamma-ray spectrometry for SLRNs’ rapid multielement determination. By targeting SLRNs such as 77mSe, 110Ag, 20F, 179mHf, 52V, and 46mSc, with half-lives from seconds to minutes, the method enables quantification of elements essential for biological and environmental research. The in-house developed “k0-Dalat” software, featuring high automation, supports complete analysis. Method accuracy was validated using certified reference materials (SMELS-I, NIST-SRM-1566b, NIST-SRM-2711a), achieving deviations under 8% from certified values. Detection limits ranged from 0.1 to 1.9 mg/kg for target elements in biological samples, confirming the method’s high sensitivity and suitability for similar matrices.
Acknowledgements
The authors acknowledge the support of the IAEA (RER/4/028), ISINN-31 Conferenceorganizers, and VINATOM. The authors are grateful to the Dalat research reactor operatorsfor their collaboration in establishing and maintaining the fast irradiation facility. The authorsalso thank the technical staff at the Center for Nuclear Technologies and the Dalat NuclearResearch Institute for their assistance in sample preparation and analysis.
References
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[23] H. M. Dung, T. Q. Thien, H. V. Doanh,et al., A dual method using SMELS for neutron fluxself-monitoring and quality control ink0-NAA, Journal of Radioanalytical and Nuclear Chemistry334 (2025) 49–56.
[24] IAEA TECDOC-2026, Intercomparison ofk0-NAA Software Packages, International Atomic En-ergy Agency (IAEA), Vienna, Austria, 2023.https://www-pub.iaea.org/MTCD/Publications/PDF/TE-2026_web.pdf.
[25] H. M. Dung, T. Q. Thien, H. V. Doanh, T. T. Son, P. Lathdavong, Development of a PC programfor thek0-based epithermal neutron activation analysis, Journal of Radioanalytical and NuclearChemistry 332 (8) (2022) 3469–3474.
[26] S. Pomm ́e, Dead Time, Pile-Up, and Counting Statistics,in: Applied Modeling and Computationsin Nuclear Science, ACS Symposium Series 945, American Chemical Society, Washington, D. C.,2006, pp. 218–233.
[27] L. A. Currie, Limits for qualitative detection and quantitative determination: Application toradiochemistry, Analytical Chemistry 40 (3) (1968) 586–593.
[28] S. Sudar, TrueCoinc, a Software Utility for Calculation of the True Coincidence Correction,in:IAEA-TECDOC-1275 (2002) 37–48.
[29] S. Jovanovi ́c, A. Dlabaˇc, N. Mihaljevi ́c, P. Vukoti ́c, ANGLE: A PC-code for semiconductordetector efficiency calculations, Journal of Radioanalytical and Nuclear Chemistry 218 (1997)13–20.
[2] R. Dams, Selection of short-lived isotopes for activation analysis with respect to sensitivity, Journalof Radioanalytical Chemistry 61 (1–2) (1981) 13–36.
[3] IAEA-TECDOC-2055, Neutron Activation Analysis Using Short Half-Life Radionuclides, Inter-national Atomic Energy Agency (IAEA), Vienna, Austria, 2024.https://www-pub.iaea.org/MTCD/Publications/PDF/TE-2055web.pdf.
[4] J. Versieck, Neutron activation analysis for the determination of trace elements in biologicalMaterials, Biological Trace Element Research 9 (1994) 407–413.
[5] G. L. Moln ́ar, Zs. R ́evay, L. Szentmikl ́osi, New perspectives for very short-lived neutron activationanalysis, Journal of Radioanalytical and Nuclear Chemistry 262 (1) (2004) 157–163.
[6] A. Chatt, K. N. Desilva, J. Holzbecher, D. C. Stuart, R. E. Tout, D. E. Ryan, Cyclic neutronactivation analysis of biological and metallurgical samples, Canadian Journal of Chemistry 59(1981) 1660.
[7] N. M. Spyrou, Cyclic activation analysis — A review, Journal of Radioanalytical Chemistry 61(1–2) (1981) 211–242.
[8] H. Zhang, Z. F. Chai, W. Y. Qing, H. C. Chen, Cyclic neutron activation analysis for determinationof selenium in food samples using77mSe, Journal of Radioanalytical and Nuclear Chemistry 281(2009) 23–26.
[9] Y. Shi, E. E. Suww, J. Holzbecher, A. Chatt, Determination of selenium in Canadian food items bycyclic instrumental neutron activation analysis, Biological Trace Element Research 71–72 (1999)377–386.[10] N. D. Nguyen, B. V. Luong, V. V. Le, V. D. Duong, X. H. Nguyen, N. S. Pham, D. V. Cao, Resultsof operation and utilization of the Dalat nuclear research reactor, Journal of Nuclear Science andTechnology 4 (1) (2014) 1–9.[11] A. Simonits, F. De Corte, J. Hoste, Single-comparator methods in reactor neutron activationanalysis, Journal of Radioanalytical and Nuclear Chemistry 24 (1) (1975) 31–46.[12] F. De Corte, Thek0Standardization Method — A Move to the Optimization of NAA, Rijksuni-versiteit Gent, Belgium, 1987.[13] H. M. Dung, P. D. Hien, The application and development ofk0-standardization method of neu-tron activation analysis at the Dalat research reactor, Journal of Radioanalytical and NuclearChemistry 257 (3) (2003) 643–647.[14] B. Smodiˇs, R. Ja ́cimovi ́c, S. Jovanovi ́c, P. Stegnar, Determination of trace elements in standardreference materials by thek0-standardization method, Biological Trace Element Research 26–27(1) (1990) 43–51.[15] H. M. Dung, M. Blaauw, D. Beasley, M. D. C. Freitas, Development of thek0-based cyclic neutronactivation analysis for short-lived radionuclides, Journal of Radioanalytical and Nuclear Chemistry291 (2) (2011) 485–492.
[16] R. Acharya, K. B. Dasari, D. Chandra Shekhar, T. P. Chaturvedi, P. K. Pujari, Performance ofdigital gamma ray spectrometer for loss free counting and its application to NAA using short-livedradionuclides, Journal of Radioanalytical and Nuclear Chemistry 302 (3) (2014) 1333–1337.
[17] M. Blaauw, R. F. Fleming, R. Keyser, Digital signal processing and zero-dead-time counting,Journal of Radioanalytical and Nuclear Chemistry 248 (2) (2001) 309–313.
[18] V. D. Ho, M. D. Ho, T. V. Ha, Q. T. Tran, D. V. Cao, The upgrading of the cyclic neutronactivation analysis facility at the Dalat research reactor, Journal of Radioanalytical and NuclearChemistry 315 (3) (2017) 703–709.
[19] V. D. Ho, M. D. Ho, Q. T. Tran, T. S. Nguyen, N. D. Nguyen, Combination and optimization ofthe cyclic NAA modes at the Dalat research reactor for determination of selenium in biologicalmaterials using77mSe, Journal of Radioanalytical and Nuclear Chemistry 309 (1) (2016) 185–188.
[20] P. Vermaercke, P. Robouch, M. Eguskiza, F. De Corte, G. Kennedy, B. Smodiˇs, R. Ja ́cimovi ́c,C. Yonezawa, H. Matsue, X. Lin, M. Blaauw, J. Kuˇcera, Characterisation of synthetic multi-element standards (SMELS) used for the validation ofk0-NAA, Nuclear Instruments and Methodsin Physics Research A 564 (2) (2006) 675–682.
[21] F. De Corte, A. Simonits, Recommended nuclear data for use in thek0standardization of neutronactivation analysis, Atomic Data Nuclear Data Tables 85 (1) (2003) 47–67.
[22] H. M. Dung, S. Y. Cho, A simple method for alpha determination, Journal of Radioanalyticaland Nuclear Chemistry 257 (3) (2003) 573–575.
[23] H. M. Dung, T. Q. Thien, H. V. Doanh,et al., A dual method using SMELS for neutron fluxself-monitoring and quality control ink0-NAA, Journal of Radioanalytical and Nuclear Chemistry334 (2025) 49–56.
[24] IAEA TECDOC-2026, Intercomparison ofk0-NAA Software Packages, International Atomic En-ergy Agency (IAEA), Vienna, Austria, 2023.https://www-pub.iaea.org/MTCD/Publications/PDF/TE-2026_web.pdf.
[25] H. M. Dung, T. Q. Thien, H. V. Doanh, T. T. Son, P. Lathdavong, Development of a PC programfor thek0-based epithermal neutron activation analysis, Journal of Radioanalytical and NuclearChemistry 332 (8) (2022) 3469–3474.
[26] S. Pomm ́e, Dead Time, Pile-Up, and Counting Statistics,in: Applied Modeling and Computationsin Nuclear Science, ACS Symposium Series 945, American Chemical Society, Washington, D. C.,2006, pp. 218–233.
[27] L. A. Currie, Limits for qualitative detection and quantitative determination: Application toradiochemistry, Analytical Chemistry 40 (3) (1968) 586–593.
[28] S. Sudar, TrueCoinc, a Software Utility for Calculation of the True Coincidence Correction,in:IAEA-TECDOC-1275 (2002) 37–48.
[29] S. Jovanovi ́c, A. Dlabaˇc, N. Mihaljevi ́c, P. Vukoti ́c, ANGLE: A PC-code for semiconductordetector efficiency calculations, Journal of Radioanalytical and Nuclear Chemistry 218 (1997)13–20.