Conceptual Study of a Calibrated Radon Source and a Portable Radon Detector PDF Download

Author: Aamer Bashir
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Languages : en
Pages : 0

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Book Description
Accurate assessment of radon concentration in indoor air can determine whether the environment poses a lung cancer risk. A radon calibration system is being developed and studied that dispenses custom and reproducible activities of radon from a radon generator source into a vessel for sensor testing and calibration. There are two methods by which radon can be dispensed into the vessel. The flow-through method allows for radon to be pumped at a constant activity and flow rate through the chamber, with concentrations ranging from 1.7 pCi/l to 34 pCi/l. The vacuum method injects a predefined concentration of radon into the chamber, starting from 85 pCi/l. Both methods have their advantages and disadvantages. To accurately detect alpha particles emitted by radon and its progeny, a portable alpha particle detector using a silicon PIN photodiode is being developed. The current lab system setup using a $10 Hamamatsu photodiode yields a 1.82% channel resolution using polonium-210 as an alpha source. A detector with sufficient energy resolution is needed to resolve individual alpha peaks in an energy spectrum produced by various radionuclides present in air. Background radiation experiments have shown that the detector exhibits an excellent signal-to-noise ratio. Lab counting experiments have shown the experimental activity is in reasonable agreement with the calculated radiation incident on the photodiode. Current circuit development includes a charge sensitive preamplifier, and the remaining goal is to add a pulse counting chain to complete the circuit and the portable alpha particle counter. In the future, it is planned to extensively calibrate the alpha particle detector with the radon calibration system.