Stability of polymeric scintillating resins developed for ultra-trace level detection of alpha- and beta-emitting radionuclides

Scintillation and structural properties of copolymers and mixtures of styrene, 9-vinylcarbazole and 4-vinylbenzyl chloride based plastic scintillators

The research team has developed new plastic scintillators in the form of microspheres, called PSm, by combining styrene, 9-vinylcarbazole (VK), and 4-vinylbenzyl chloride (VBC). The primary objective of this study was to explore the feasibility of incorporating the fluorescent solute (VK) into the polymer structure to prevent its leaching out when PSm are utilized in liquid flow through detection systems or organic solvents. The secondary aim was to examine the impact of adding the chlorine functional group to the scintillation polymer, with the intention of replacing it with an extractant in the future to create covalently linked PSresins. The findings of the study reveal that the homopolymer of polyvinylcarbazole (PVK) performs poorly while used as a unitary scintillator system for plastic scintillation measurements. However, the incorporation of monomers in the form of copolymers with styrene has a more significant impact on scintillation properties compared to the mixture of homopolymers. In the case of 9-vinylcarbazole (VK), its presence at a weight proportion of 10% leads to an increase in scintillation efficiencies, although it is still inferior to the classical PS. Conversely, the situation is different for 4-vinylbenzyl chloride (VBC), where the chlorine in the copolymer results in higher quenching, and the polymer is also less resistant to organic solvents due to the formation of short polymer chains. For VBC, the mixture of polymers yields better results and enables the production of covalently linked PSresins.

The use of plastic scintillation microspheres in flow scintillation analysis

This manuscript deals with the possible utilization of plastic microspheres for radiation detection. The aim was to determine the suitability of microspheres for this application, factors that affect detection efficiency, and based on the evaluation of current state technology to design and test a constructional solution suitable for this use. Three detection cell variations and their configurations, which utilize plastic microspheres, were tested for their response to selected militarily important radionuclides during a series of static measurements. Based on the results of static measurements, the most structurally suitable cell variation was subsequently tested for flow scintillation analysis. Among the cells designed for flow scintillation counting in 2π geometry, the highest achieved detection efficiency for 241Am was 13.1 ± 0.7% using Cell #5, for 90Sr/Y was 71.2 ± 3.9% using Cell #10 and for 3H was 3.9 ± 0.2% using Cell #5 respectively. Cell #10 was evaluated to perform universally the best despite achieving slightly lower detection efficiencies for 241Am and 3H than Cell #5, as the results were easily replicable and due to the cell constructional simplicity, its application was problem-free.