Measurement for activity concentrations of αβ artificial radionuclides in the environment with αβ spectrometry

The paper introduces the method of determining the volume activity concentration of α transuranium and total β artificial radionuclides in the environment, and Rn/Th progeny background-compensation by αβ spectrometry. By measuring the α counts of RaA and RaC' in two time intervals, the activity concentration of RaA, RaB, RaC can be evaluated, meanwhile, the total β counts of RaB, RaC aerosol also can be determined. The α counts of transuranic aerosol can be determined by subtracting the trail counts of RaA and RaC' α peaks in each time interval. Under average equilibrium factor of Th progeny in general environment, the α counts can be corrected by the α counts of ThC' peak. The total β counts of β artificial radionuclides can be determined by subtracting the β counts of RaB, RaC and ThB, ThC. Sampling 20 min, waiting 2 min, measuring 2-15 and 15-40 min can keep the total errors of Rn progeny concentration less than 15% under the measuring arrangement (KB-250E sampler, Model 49 glass fiber, 190 l/min). If the Rn progeny concentration is less than 15 Bqm-3, the low detected limit (LDL) will be less than 0.1 Bqm-3. The lower Rn progeny concentration, the lower the LDL will be. Even if the Rn progeny concentration is so high as 75 Bqm-3, the LDL of total β aerosol activity concentration will be less than 1 Bqm-3, on the other hand, for the general environment, the LDL will be less than 0.5 Bqm-3