The Ambient Dose Equivalent Measurement by the Spectro-Dosimeter Method in the NaI(Tl) Detector

Document Type : Original Article

Authors

1 urmia university

2 Urmia university

3 Imam Hossein University

Abstract

A minimum level of radiation needs to be detected for determining the value of the radiation dose equivalent. Typically, the output of a nuclear radiation detector cannot be used directly for determining the value of the radiation dose equivalent. Via changing the response function or the readout of the detector, effort is made to obtain a logical relation between the output of the detector and the dose equivalent. For this purpose, various hardware and software methods are used. In this research, the ambient dose equivalent H*(10) of gamma radiation is determined by applying the spectro-dosimeter method, which is based on the software method. In this method, the readout of the NaI(Tl) detector is subdivided into several energy intervals based on the pulse height, thereby, each energy interval has its own conversion factor. Conversion coefficients are obtained by using the Gaussian elimination method. The ambient dose equivalent H*(10) is determined from the detector readout without spectra deconvolution. Using the Geant4 Monte Carlo code simulation, the response function and the readout of the NaI(Tl) detector for gamma radiation are determined and then the conversion coefficients are calculated for obtaining the ambient dose equivalent. Fairly good agreement is observed between the simulation data and experimental results for the detector response function. The results show that by finding the conversion coefficients function in the energy range of 0.03-3 MeV in this dosimetric method for values equivalent to the ambient dose of gamma the measurement error percentage decreases and the measurement accuracy increases.

Keywords


  1. Saray, A. A.; Dizaji, H. Z. “Simulation and Measurement of Cadmium Ratio Parameter in the Polyethylene Pile”; J. Passive Defence Sci. & Technol. 2017, 8, 321-328.##
  2. Attix, F. H. “Introduction to Radiological Physics and Radiation Dosimetry”; Wiley, 2008.##
  3. Wang, A.; Zhou, R.; Yang, C. “Verification of The Method of Average Angular Response for Dose Measurement on Different Detectors”; Instrum. 2015, 47, 701-708.##
  4. Buzhan, P.; Karakash, A.; Teverovskiy, Y. “Silicon Photomultiplier and CsI (Tl) Scintillator in Application to Portable H*(10) Dosimeter”; Nucl. Instrum. Methods Phys. Res. Sect. A. 2018, 912, 245-249.##
  5. Knoll, G. “Radiation Detection and Measurement”; 3rd Edition, Wiley, New York, 1999.##
  6. Wear, J. A.; Karp, J. S.; Haigh, A. T.; Freifelder, R. “Evaluation of Moderately Cooled Pure NaI as a Scintillator for Position-Sensitive PET Detectors”; IEEE Trans. Nucl. Sci. 1996, 43, 1945-1951.##
  7. Thanh, T.; Nguyen, V.; Chuong, H.; Tran, L.; Tam, H.; Thi Binh, N.; Tao, C. “Verification of Compton Scattering Spectrum of a 662 keV Photon Beam Scattered on a Cylindrical Steel Target using MCNP5 Code”; Appl. Radiat. Isot. 2015, 105, 294-298.##
  8. Kin, T.; Goto, J.; Oshima, M. “Machine Learning Approach for Gamma-ray Spectra Identification for Radioactivity Analysis”; IEEE Trans. Nucl. Sci. 2019, 4, 1-2.##
  9. Kleinknecht, K. “Detectors for Particle Radiation”; 2ed Ed. Cambridge, U.K, 1998.##
  10. Balcezyk, M.; MoszyƄski, M.; Kapusta, M. “Comparison of LaCl3: Ce and NaI (Tl) Scintillators in Gamma-ray Spectroscopy”; Nucl. Instrum. Methods Phys. Res. Sect. A. 2005, 537, 50-56.##
  11. Eissa, M.; Arafa, H. “Improve the Efficiency of Scintillation Detectors Using Reflectors Based on Photonic Crystals Array”; Electromag. Anal. Appl. 2014, 6, 25-29.##
  12. Sharp, P.; Barber, D. C.; Brown, D. G.; Burgess, A. E.; Metz, C. E.; Myers, K. J.; Taylor, C. J.; Wagner, R. F.; Brooks, R.; Hill, C. R.; Kuhl, D. E.; Smith, M. A.; Wells, P.; Worthington, B. “International Commission on Radiation Units and Measurements”; Report 54, Quantities and Units in Radiation Protection Dosimetry, 1996.##
  13. “Measurement of Dose Equivalents from External Photon and Electron Radiation”; Report 47, 1992.##
  14. Agostinelli, S.; Allison, J.; Amako, K.; Apostolakis, J.; Araujo, H.; Arce, P.; Asai, M.; Axen, D.; Banerjee, S.; Barrand, G.; Behner, F.; Bellagamba, L.; Boudreau, J. “Geant4-a Simulation Toolkit”; Nucl. Instrum. Methods Phys. Res. A. 2003, 506, 250-303.##
  15. Iddings, F. A.; Lieber, T. J.; Williams, O. W. “Counting Yield Calibration of NaI(Tl) Detectors for Complex Geometry Samples by Use of Californium-252”; Radioanal. Nucl. Chem. 1979, 50, 125-131.##
  16. Conway, J. T. “Analytical Solution for the Solid Angle Subtended at Any Point by an Ellipse Via a Point Source Radiation Vector Potential”; Nucl. Instrum. Methods Phys. Res. Sect. A. 2010, 604, 17-27.##
  17. Casanovas, R.; Morant, J. J.; Salvadó, M. “Development and Calibration of a Real-time Airborne Radioactivity Monitor Using Direct Gamma-ray Spectrometry with Two Scintillation Detectors”; Appl. Radiat. Isot. 2014, 89, 102-108.##
  18. Rahman, M. S.; Gyuseong, C. “Unfolding Low-Energy Gamma-ray Spectrum Obtained with NaI(Tl) in Air Using Matrix Inversion Method”; J. Sci. Res. 2010, 2, 221-226.##
  19. Dizaji, H. Z. “Energy Response Improvement for Photon Dosimetry Using Pulse Analysis”; Chinese Phys. C 2016, 40,##
  20. Lotfi, Y.; Dizaji, H. Z.; Davani, F. A. “Detection and Dosimetry Studies on the Response of Silicon Diodes to a 241Am-Be Source”; J. Instrum. 2014, 9, 06023.##
  21. Dombrowski, H. “Area Dose Rate Values Derived from NaI or LaBr3 Spectra”; Radiat. Prot. Dosimetry 2014, 160, 269-276.##
  22. Crewson, C.; Rangacharyulu, C. “Photon Mass Attenuation Coefficients of Importance to Dosimetry”; IEEE Trans. Nucl. Sci. 2011, 6, 626-931.##
  23. Pan, V. Y.; Zhao, L. “Numerically Safe Gaussian Elimination with no Pivoting”; Linear Algebra Appl. 2017, 527, 349-383.##
  24. Shi, H. X.; Chen, B. X.; Li, T. Z.; Yun, D.; “Precise Monte Carlo Simulation of Gamma-Ray Response Functions for an NaI(Tl) Detector”; Appl. Radiat. Isot. 2002, 57, 517 – 524.##
  25. Salgado, C. M.; Brandão, L. E. B.; Schirru, R. “Validation of a NaI(Tl) Detector’s Model Developed with MCNP-X Code”; Prog. Nucl. Energy 2012, 59, 19–25.##
  26. Karabekir, K.; Bilimler, T.; Yüksekokulu, M.; Bölümü, “A Study on Calculation of Full Energy Peak Efficiency of NaI (Tl) Detectors using Point Source”; J. Theor. Appl. Phys. 2019, 6, 28-36.##
  27. Moszyniski, M.; Nassalski, A.; Syntfeld-Kazuch, A.; Swiderski, L.; Szczecsniak, T. “Energy Resolution of Scintillation Detectors- New Observations”; IEEE Trans. Nucl. Sci. 2008, 55, 1062-1068.##
  28. Röttger, A.; Kessler, P. “Uncertainties and Characteristic Limits of Counting and Spectrometric Dosimetry Systems”; Environ. Radioact. 2019, 205, 48-54.##