Journal of Radiation Safety and Measurement

Journal of Radiation Safety and Measurement

Computational investigation of time parameters and the effect of sample matrix on signal-to-noise ratio in cyclic neutron activation analysis for 77mSe in rice flour

Document Type : Original Article

Authors
Neda Nemati 1
Mohammad Hosein Choopan Dastjerdi 2
Javad Mokhtari 2
1 Nuclear Engineering Department, Faculty of Physics, University of Isfahan, Iran
2 Reactor and Nuclear Safety Research School, Nuclear Science and Technology Research Institute, AEOI, Isfahan, Iran
10.22052/rsm.2026.257174.1138
Abstract
Cyclic neutron activation analysis (CNAA) is an advanced, accurate, and nondestructive method for the identification of short-lived radioactive isotopes that is based on the repetition of three steps of irradiation, transfer, and counting of the sample in the form of designed time cycles. The success of this method depends on the precise design and optimization of the time parameters of each step, as well as the correct knowledge of the composition of the sample matrix. In this study, using analytical equations, the effect of parameters such as irradiation time ti, transfer or decay time td, counting time tc, number of cycles n, and sample matrix structure on the signal-to-noise ratio (SNR) has been investigated. The results showed that for irradiation and counting times, there is an optimal range outside which the SNR parameter decreases significantly. In the case of transfer time, the findings also indicate that by reducing this time to values close to zero, the effective signal is maintained and the SNR increases. Also, increasing the number of cycles generally improves the SNR, although its growth rate decreases at high cycles. Since the composition of the sample matrix is not changed in this type of analysis, the elements present in it were also investigated. Analysis of the role of the sample matrix also showed that some elements present in the sample composition can affect the quality of the response through the production of interfering isotopes and spectral interference.
Keywords
Cyclic neutron activation analysis
short-lived isotopes
irradiation time
transmission time
signal-to-noise ratio
interfering isotopes
optimization of time parameters
sample matrix
  1. W. W. Givens, W. R. Mills Jr, R. L. Caldwell. Cyclic activation analysis. Vol. 2. National Bureau of Standards, Special Publication 312, 80 (1969) 95-103.
  2. N. Spyrou. Cyclic activation analysis—A review. J. Radioanal. Nuclear Chem.61 (1-2) (1981) 211-242.
  3. X. Hou. Cyclic activation analysis. Encyclopedia Anal. Chem.: Appl. Theory Instrum. (2000) 12447-12459.
  4. C. S. Munita, M. D. Glascock, R. Hazenfratz. Neutron activation analysis: An overview. In the book: Recent advances in analytical techniques. Vol. 3. (Ed. by Atta-ur-Rahman, S. A. Ozkan). Bentham Science Publishers, (2019) 179-227.
  5. R. R. Greenberg, P. Bode, E. A.  De Nadai Fernandes. Neutron activation analysis: A primary method of measurement. Spectrochimica Acta Part B: Atomic Spectroscopy66 (3-4) (2011) 193-241.
  6. R. E. Tout, A. Chatt. The effect of sample matrix on selection of optimum timing parameters in cyclic neutron activation analysis. Anal. Chimica Acta133 (3) (1981) 409-419.
  7. M. A. Al-Mugrabi, N. M. Spyrou. The use of simulation for the optimisation of the signal-to-noise ratio in cyclic activation analysis. J. Radioanal. Nuclear Chem.110 (1987) 67-77.
  8. O. M. H. Ahamed. Simulation for sodium-24 production using cyclic neutron activation analysis. (No. INIS-SD--531). Sudan Academy of Sciences, Khartoum (2012).
  9. C. A. Lani, D. P. Bruce. M. L. Stephanie, M. Flaska. Optimization Simulations for a Gamma-Ray Calibration Standard for a Cyclic Neutron Activation Analysis Pneumatic System at the Penn State Breazeale Reactor. In 2021 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), Piscataway, NJ, USA (2021) pp. 1-4.
  10. T. Weizhi, N. Bangfa, W. Pingsheng, N. Huiling. Suitability of NAA for certification of reference materials for multielements. J. Radioanalytical Nucl. Chem. 245 (1) (2000) 51-56.
  11. H. Zhang, Z. Chai, W. Qing, H. Chen. Cyclic neutron activation analysis for determination of selenium in food samples using 77m Se. J. Radioanalytical Nucl. Chem. 281 (1) (2009) 23-26.
  12. W. Zhang, A. Chatt. Determination of selenium in foods by pseudo-cyclic neutron activation and anti-coincidence gamma-ray spectrometry. J. Radioanalytical Nucl. Chem.282 (2009) 139-143.
  13. U. M. El-Ghawi, A. A. Al-Sadeq, M. M. Bejey, M. B. Alamin. Determination of selenium in Libyan food items using pseudocyclic instrumental neutron activation analysis. Biol. Trace Elem. Res.107 (1) (2005) 61-71.
  14. I. J. Kim, P. W. Russell, M. L. Richard. Accurate and precise measurement of selenium by instrumental neutron activation analysis. Analytical Chem.83 (9) (2011) 3493-3498.
  15. S. Hevia, S. Resnizky, A. Chatt. Selenium content of Argentinean infant formulae and baby foods by pseudo-cyclic instrumental neutron activation analysis coupled to Compton suppression. J. Radioanal. Nuclear Chem.297 (2013) 383-391.
  16. R. R. Greenberg, S. K. Jean, T. E. Gills. Certification of a new NIST fly ash standard reference material. Fresenius' J. Analytical Chem.352 (1995) 193-196.
  17. M. M. Phillips, E. S. Katherine, S. A. Wise. Standard reference materials for food analysis. Anal. Bioanal. Chem. 405 (13)  (2013) 4325-4335.
  18. D. L. Anderson, C. William. Revalidation and long-term stability of National Institute of Standards and Technology Standard Reference Materials 1566, 1567, 1568, and 1570. J. AOAC Int. 83 (5) (2000) 1121-1134.