Field Evaluation of an Encapsulated 226Ra–222Rn Source

A closed container having a specified quantity of ²²⁶Ra was constructed as encapsulated ²²⁶Ra–²²²Rn source. The source in the form of a modified Lucas cell (LC) was used for standardization of Lucas cell alpha counting system. The performance of the prepared source was evaluated by simultaneous measurement of dissolved radon in water by Lucas cell method using alpha counting system and Alpha guard. Radon alpha counting system measures dissolved radon in water sample by gross alpha counting of aerated dissolved transferred to LC. The same samples were also measured simultaneously by Alpha guard using instant measurement of emanated radon in a closed circuit. The gross alpha counting method using the radon counting system produced result that is closely matching with the Alpha guard measurement. This validates the calibration of radon counting system by designed encapsulated source. The study provides an alternative for calibration in the absence of expensive radon source available in the market.