Conventionally, radioactivity is detected through ionization of gas, typically inert gas, by ionizing radiations emitted from radioactive materials. When exposed to ionizing radiation, naturally insulating gases become locally ionized, meaning that positively charged alpha particles remove electrons from gas atoms; as a result electrically neutral gas atoms become ionized with positive charge. The whole process results in a temporary and incremental increase in conductivity of the gas that can be detected via proper electronic equipment. The drawbacks of the current state-of-the-art ionizing radiation detection systems are: 1) need for high potential deference between electrodes (due to extremely low conductivity of gases); and 2) need for gas tubes (Geiger-M�ller tubes) to increase sensitivity, which prevent networking of detectors for real-time monitoring of large areas. In this work, we have investigated the response of doped conjugated polymers as sensors for detection of ionizing radiation. Conjugated polymers have delocalized electrons that can be paired with alpha particles and change electrical properties of the conjugated polymers. This change in electrical properties can be easily detected by ordinary electronic equipment. The main advantages over the current systems are that doped conjugated polymers are conductive; thus, a significantly smaller potential deference between the electrodes will be required for detection. Most importantly, small pieces of doped conjugated polymers can be used to form network of sensors, to construct a large detector to monitor radiations over large areas (nuclear power plants, nuclear submarines, government buildings, military bases, etc.) Conductivity of conjugated polymers can be fine-tuned by level of doping and synthesis methods to control sensitivity of the sensors. Moreover, conjugated polymers can be synthesized to detect beta particles; use of undoped conjugated polymers is more suitable for detection of beta particles.

Conjugated polymers for ionizing radiation detection

247th National Meeting (2014)

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