Accelerated Radiation Transport Modeling Techniques for Pencil Beam Computed Tomography using Gamma Rays
Monte Carlo radiation transport modeling studies were performed for a compact, and high-resolution gamma-ray computed tomography system designed for imaging irradiated nuclear fuel. The system comprises a 60Co source – chosen for its highly penetrating 1173 keV and 1332 keV gamma rays – a pair of high-aspect-ratio pencil beam collimators, and an inorganic scintillator detector. Two acceleration methods are proposed to rapidly model a transmission type gamma-ray tomography system. The first, a variance reduction technique, is based on performing Monte Carlo simulations with a monodirectionally-biased source, sampled from a characteristic sub-volume of the full source volume. The second acceleration method is based on the deterministic calculations using the Beer–Lambert law and detector response characteristics. Comparison of simulations using acceleration approaches with analog simulations of the fully isotropic, full-volume equivalent, show that the Monte Carlo variance reduction technique gives quantitatively accurate predictions for large collimator aspect ratios while the deterministic calculations are semi-quantitative but converge close to the correct result as the collimator aspect ratio increases. As such, these techniques can be used to reduce the computational cost in generating simulated radiographs and tomographs by several orders of magnitude. Experimental validation efforts are currently underway and will be demonstrated in future work.
Z. Jin et al., "Accelerated Radiation Transport Modeling Techniques for Pencil Beam Computed Tomography using Gamma Rays," Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 1039, article no. 167165, Elsevier, Sep 2022.
The definitive version is available at https://doi.org/10.1016/j.nima.2022.167165
Nuclear Engineering and Radiation Science
Keywords and Phrases
Gamma-ray tomography; Monte Carlo; Non-destructive testing; Nuclear fuel; Radiation transport
International Standard Serial Number (ISSN)
Article - Journal
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11 Sep 2022