INVESTIGATING THE CHARACTERISTICS OF LARGE-VOLUME PVT SCINTILLATION DETECTORS IN THE RADIATION PORTAL MONITORS USING MONTE CARLO SIMULATIONS
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https://doi.org/10.54939/1859-1043.j.mst.75A.2021.52-59Keywords:
Radiation portal monitors (RPMs); Scintillation detectors; Monte Carlo simulation method.Abstract
This paper presents the characteristics determination process of the large-size Polyvinyl Toluene (PVT) scintillation detectors using MCNP5 simulation code. The energy spectra using a 137Cs calibration source, absolute efficiency in the energy range of 50 ÷ 3000 keV, and the angular response of the EJ-200 50×50×5 cm3 and 25×25×5cm3 are investigated. The simulated energy spectra are in good agreement with the experimental spectra. The results of determining the absolute efficiency show that the EJ-200 50×50×5 cm3 and 25×25×5cm3 plastic detectors have detection efficiencies of 16,3% and 9,2%, respectively, at 10cm source-to-detector distance, and down to 0,6% and 0,17% at 100 cm source-to-detector distance. The angular responses of the detectors show that the detection efficiency value reached ≥ 90% of the maximum value with the incident angle less than 5π/6. The results can be applied in the process of design optimization of plastic-based radiation portal monitors.
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