Optimization Study of a Muon Tomography System for Imaging of Nuclear Waste Containers |
| A. Georgadzea, b
aInstitute for Nuclear Research, prospekt Nauky b.47, 03680, Kyiv, Ukraine bInstitute of Physics, University of Tartu, W. Ostwaldi 1, 50411, Tartu, Estonia |
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| For the non-destructive characterization of nuclear waste, muon scattering tomography techniques can be used to image the contents of a concrete-filled steel drum to verify the presence of nuclear materials. The purpose of this study was to compare two possible detector schemes in terms of their performance in localizing nuclear materials. One of the detector schemes consists of two horizontal muon trackers placed above and below the nuclear waste container. Another detector scheme consists of a horizontal upper and a lower tracker and two vertical side trackers. It is expected that side trackers may improve the accuracy of the vertical coordinate determination. For quantitative analysis of detector performance, we have used ROOT CERN tools to perform automated analysis of muon scattering tomography data for detection of dense objects of high-Z materials inside concrete-filled waste drums. GEANT4 toolkit combined with cosmic-ray shower generator was applied to simulate the transport and interactions of muons. Analyzing the simulated data, it was found that due to the loss of energy by muons during ionization processes in the concrete matrix, their spectrum becomes softer, the probability of multiple Coulomb scattering increases, and, accordingly, the muon scattering angles increase. This effect resulted in a point-of-closest-approach signal from the 5 cm tungsten cube placed at the bottom of a nuclear waste container stronger than the signal from the cube at the top. The coordinates (x,y,z) of lead and tungsten cubes were successfully localized in a one-hour measurement time with an accuracy of several millimeters for both detector geometries, indicating that both schemes are compatible. |
DOI:10.12693/APhysPolA.142.391 topics: muon tomography, radioactive waste, particle tracking, GEANT4 toolkit |