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Application Specific Integrated Circuits for Direct X-Ray and Gamma-Ray Conversion in Security Applications
Published in Choi Jung Han, Iniewski Krzysztof, High-Speed and Lower Power Technologies, 2018
Krzysztof Iniewski, Chris Siu, Adam Grosser
Detection of the nuclear materials needs to overcome potential attenuation and shielding effects. Various techniques for X-rays, gamma rays and neutrons are being utilized in the security applications. Many of the detection devices use large sheets of plastic scintillator material, such as polyvinyltoluene (PVT), to detect radiation coming from unknown sources. PVT is doped with anthracene or other wavelength-shifting dopants to produce a plastic scintillator. When subjected to ionizing radiation (both particle radiation and gamma radiation), the amount of visible radiation emitted is proportional to the absorbed dose.
Effect of fluorescent dyes on the scintillation efficiency, improved light yield and radiation hardness of polystyrene-based plastic scintillator: a comparative study
Published in Radiation Effects and Defects in Solids, 2023
Lizbeth Alex, Rajesh Paulraj, Mohit Tyagi
The thermal bulk polymerization method produces plastic scintillators marked by high light output mainly due to its homogeneity (14). The temperature profile is modulated to control the dissipation of heat and to avoid the effects of polymerization shrinkage and thus to obtain optically homogeneous scintillators. The influence of polymerization temperature also affects the luminescence output of the plastic scintillators. Plastic scintillators prepared at higher temperature range of 80–150°C, falling within the molecular weight of 100,000–1,000,000, have reported significant light yield independent of the chain length (13) whereas increasing above 140°C and 175°C for polystyrene and polyvinyltoluene based plastic scintillators respectively decreases the light yield (15). The average molecular weight tends to be lower and the polymer chain is involved in the energy transfer process at higher polymerization temperature, which results in more uniform structure and high relative light yield (16).
Location and Activity Characterization of Gamma-Ray Point Sources Concealed in Shipping Containers Using Iterative Reconstruction and Modeling Cargo-Specific Attenuation
Published in Nuclear Technology, 2023
Euan L. Connolly, Dean T. Connor, Peter G. Martin
By strategically positioning RPM infrastructure along vehicular borders/points of entry, both traffic and cargo can be rapidly and noninvasively screened for concealed illicit RNs that have the potential for use within radiological dispersal devices or improvised nuclear explosive devices. To maximize throughput, multiple RPMs are often deployed across adjacent traffic lanes, utilizing large cross-section scintillator detectors to maximize the amount of radiation incident onto such a detection volume, and therefore, increasing the sensitivity and likelihood of detection events.[2] Polyvinyl-toluene (PVT)-based scintillator panels are ideal for this purpose, as they can be cost-efficiently manufactured with large, ~1 m2, cross sections.[3]