Rapid Determination of Gross Alpha/Beta Activity in Water Based on Reverse Osmosis Membrane Enrichment Pretreatment

Table 2

Measurement uncertainty of total α in each region.

Sites	Reverse osmosis membrane method			Thick source method
	urel(Cα) (%)	u(Cα) (Bq·L^−1)	U(Cα) (k = 2) (Bq·L^−1)	urel(Cα) (%)	u(Cα) (Bq·L^−1)	U(Cα) (k = 2) (Bq·L^−1)
1	12.5	0.004	0.035 ± 0.009	14.7	0.005	0.032 ± 0.009
2	14.0	0.007	0.051 ± 0.014	10.6	0.005	0.047 ± 0.010
3	15.6	0.010	0.062 ± 0.019	16.4	0.010	0.059 ± 0.019
4	16.3	0.018	0.109 ± 0.036	19.3	0.020	0.105 ± 0.041
5	15.1	0.007	0.048 ± 0.014	13.5	0.006	0.045 ± 0.012
Average value	14.7			14.9

u_rel(C_α) is the relative uncertainty when measuring the concentration of α activity; u(C_α) is the combined uncertainty when measuring the concentration of α activity; U(C_α) is the expanded uncertainty when measuring the concentration of α activity (coverage factor k = 2).