Background: According to the national standard of “Analytical Determination of Radium-226 in Water (GB/T 11212-1989)”

emanation-scintillation is widely used to monitor the content of 226Ra in water. Purpose: This study aims to optimize the analysis and mensuration conditions of emanation-scintillation method recommended in GB/T 11212-1989. Methods: The related parameters for mensuration of 226Ra

such as recovery rate

measuring moment and measuring instrument were investigated to identify the optimal working state by a series of experimental tests. Results: If the percent recovery indicated pretreatment loss was introduced

the mensuration result would be more accurate. The optimal measuring moment was 3?4 h after the complete collection of the Radon from the samples. The traditional FD-125 radon-thorium analyzer can be replaced by the portable AB-5R radon monitor which will be more convenient and flexible while keep the same performance. Conclusion: The relevant recommendations provide alternative solution for field measurement of 226Ra in water

and a design reference for the developing and updating of the GB/T 11212-1989 standard in future.Cited