NEUTRON SPECTRUM UNFOLDING USING VARIOUS COMPUTER CODES: A COMPARISON
169 viewsKeywords:
Unfolding; Neutron fluence; Dose equivalent; Spectrum.Abstract
Dosimetric quantities at various distances from a 30 cm diameter polyethylene sphere moderated 241Am-Be source were investigated using the Bonner sphere spectrometer system. The different international commercial unfolding codes were applied to unfold the neutron spectrum, and their shapes were compared to each other. Additionally, the integrated neutron fluence rates overall spectrum and fractional neutron fluence rates were deduced and compared between the results obtained from different unfolding codes. As an important quantity applying in radiation safety assessment, the neutron ambient dose equivalent rates were also calculated and compared to each other to verify the utility feasibilities of the codes.
References
[1]. Cruzate, J.A., Carelli, J., Gregori, B.; “Bonner sphere spectrometer”. In: Workshop on Uncertainty Assessment in Computational Dosimetry: a Comparison of Approaches. Bologna, Italia, 8–10 October (2007).
[2]. R. Bedogni, C. Domingo, A. Esposito, and F. Fern¡ndez, “FRUIT: An operational tool for multisphere neutron spectrometry in workplaces”, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 580, no. 3, pp. 1301–1309(2007).
[3]. M. Reginatto and P. Goldhagen, “MAXED, a computer code for maximum entropy deconvolution of multisphere nơtron spectrometer data”, Health Physics, Vol. 77(5), pp. 579–583(1999).
[4]. M. Matzke, “Unfolding of pulse height spectra: The HEPRO program system”, Physikalisch-Technische Bundesanstalt (PTB), Tech. Rep.(1994).
[5]. Ngoc-Thiem Le et al.; “Neutron calibration field of a bare (_^252)Cf source in Vietnam”. Nuclear Engineering and Technology; Vol. 49, pp. 277–284 (2017).
[6]. Ngoc-Thiem Le et al.; “Characterization of a neutron calibration field with (_^241)Am-Be source using Bonner sphere spectrometer”. Applied Radiation and Isotopes; Vol. 133, pp. 68–74 (2018).
[7]. Ngoc-Thiem Le et al.; “Simulated workplace neutron fields of (_^241)Am-Be source moderated by polyethylene spheres”; Journal of Radioanalytical and Nuclear Chemistry; Vol. 321(1), pp. 313–321 (2019).
[8]. Ngoc-Thiem Le; “Establishment of Neutron Reference Fields in Vietnam: A Review”; Philippine Journal of Science; Vol. 149 (3-a), pp. 947-954, (2020).
[9]. D.A. Brown, M.B. Chadwick et al., “NDF/B-VIII.0: The 8th Major Release of the Nuclear Reaction Data Library with CIELO-project Cross Sections”, New Standards and Thermal Scattering Data, Nuclear Data Sheets, vol. 148, pp. 1-142, 2018
[10]. Parsons, Donald Kent, “NJOY Processing of ENDF/B VIII.0 Thermal Scattering Files”, LA-UR-18-25096, 2018.
[11]. ICRP, “1990 Recommendations of the International Commission on Radiological Protection”, Annals of the ICRP, vol. 21, 1991.