Table 7.

LS counting results for the second trial as obtained in the two counters. The H# quench-indicating parameter (measured in counter “B”) maps with the composition variations given in Table 6 and shows the close matching between the three uranium U cocktails (U) and the mixed U/³H cocktail (UT). The pure ³H cocktail (T) is less quenched because of the absence of uranyl nitrate ions and the yellow coloring present in the other cocktails. It also reflects a higher tritium efficiency. Values for the massic counting rate (R_U/m) are grand mean averages for the three U sources, and the values in parentheses are the standard deviations of the mean for the n = 3 sources. The values of R_UT, m_U, m_at, and ε_T for the UT cocktail were used to obtain ε_T from Eq. (4). The efficiencies for the three β⁻-emitting isotopes were obtained from the MICELLE2 calculations (Fig. 6) for the determined value of ε_T. The calculated value of (R_U/m)_calc was in turn obtained from Eq. (2) using these efficiencies and the certified isotopic massic activities (Table 2). The relative difference between the measured (R_U/m) value and calculated (R_U/m)_calc value is given as δ.

Cocktails	H#	Quantity	“B” counter	“H” counter
U (n = 3)	78.6 (8)	(Ru/m)	910.70 (34) s−1 g−1	910.16 (29) s−1 g−1
T	59.5	ε3	0.490 6	0.475 5
UT	77.7	Rut	276.61 s−1	225.54 s−1
UT		mU	0.208 83 g	0.208 83 g
UT		mTAT	82.471 Bq	82.471 Bq
UT		εT	0.442	0.431
UT		ε231Th	0.883	0.880
UT		ε234Th	0.904	0.901
UT		ε234mPa	0.997	0.997
UT		(RU/m)calc	904.1 s−1 g−1	903.4 s−1 g−1
U/UT	—	δ	0.73 %	0.75 %