A new two-phase media method for super(226) Ra activity measurement in water

A new two-phase media method was developed for determination of super(226) Ra activity in water. The method was calibrated by applying 7 standard super(226) Ra waters with known activities. The method detects alphas in two media; 80 ml of water in a glass bottle with air or a non-polar liquid such as olive oil on top of the water. Alpha particles from super(226) Ra, super(222) Rn and progeny were detected by two polycarbonate track detectors (PCTDs) which were mounted on a holder inserted in the bottle so that one PCTD is placed in water and the other in air or in the non-polar liquid. The bottles were hermetically sealed and kept for 40 or 48 d. The PCTDs in the bottles shaken every other day enhanced the sensitivity of the measurements. The Calibration Factors for the standard super(226)Ra waters, air and olive oil above water are, respectively, (7.85 + or - 0.25) x 10 super(-3), (7.94 + or - 0.13) x 10 super(-3) and 3.02 x 10 super(-2) tracks.cm super(-2) kBq super(-1) h super(-1) m super(3).