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. Author manuscript; available in PMC: 2019 Apr 1.
Published in final edited form as: Appl Radiat Isot. 2017 Jul 27;134:23–31. doi: 10.1016/j.apradiso.2017.07.050

Table 3.

Thorium molality measurement data.

Sample number Analysis lab Measured 229Th Molality (mol g−1) Ampoule number IDMS spike
21R LANL (1.1485 ± 0.0023) × 10−10 151 Dilution 2
22R LLNL (1.1498 ± 0.0024) × 10−10 Dilution 2
26R LANL (1.1489 ± 0.0018) × 10−10 126 Dilution 2
27R LLNL (1.1500 ± 0.0031) × 10−10 Dilution 2
34R CEA (1.1486 ± 0.0021) × 10−10 Dilution 2
39R LANL (1.1493 ± 0.0021) × 10−10 72 Dilution 2
41R LLNL (1.1499 ± 0.0027) × 10−10 173 Dilution 2
43R LANL (1.1492 ± 0.0026) × 10−10 49 Dilution 2
44R LLNL (1.1494 ± 0.0037) × 10−10 67 Dilution 2
45R LANL (1.1490 ± 0.0017) × 10−10 Dilution 2
46R LLNL (1.1498 ± 0.0021) × 10−10 176 Dilution 2
2R CEA (1.1491 ± 0.0024) × 10−10 41 Dilution 2
5R CEA (1.1486 ± 0.0021) × 10−10 4 Dilution 2
10R CEA (1.1482 ± 0.0021) × 10−10 82 Dilution 2
A2 LLNL (1.1497 ± 0.0019) × 10−10 17–06-1 Dilution 2A
A3 LANL (1.1476 ± 0.0035) × 10−10 Dilution 2A
A4 LANL (1.1511 ± 0.0029) × 10−10 17–06-2 Dilution 2A
B4 LLNL (1.1506 ± 0.0018) × 10−10 Dilution 2B
B2 LLNL (1.1503 ± 0.0019) × 10−10 18–02-1 Dilution 2B
B3 LANL (1.1507 ± 0.0029) × 10−10 Dilution 2B
32R LANL (1.152 ± 0.010) × 10−10 96 SRM 4342A
33R LLNL (1.156 ± 0.010) × 10−10 SRM 4342A
40R CEA (1.157 ± 0.010) × 10−10 SRM 4342A
229Th Half-life Reference Activity Based 229Th Molality (mol g−1) 229Th Half-life Value (years)
Goldstein et al. (1989) (1.158 ± 0.019) × 10−10 7880 ± 120
“A” Varga et al. (2014) (1.160 ± 0.011) × 10−10 7889 ± 64
“B” Varga et al. (2014) (1.169 ± 0.012) × 10−10 7952 ± 72
Kinkunaga et al., 2011 (1.166 ± 0.010) × 10−10 7932 ± 55

Summary of measured 229Th molality values for the reference material. Uncertainties are expanded uncertainties (U = k uc) with a coverage factor (k) of approximately 2. Reference material samples that were spiked with Dilution 2 and SRM 4342A were prepared and analyzed in 2012. Ampoule numbers associated with these samples represent filling order number. The samples spiked with Dilutions 2A and 2B were prepared and analyzed in 2015. Ampoule numbers for the later analyses represent unit identification numbers. Activity based molality values for the 229Th reference material were calculated using half-lives from cited publications and assuming a massic activity of (194.4 ± 1.1) Bq g−1. Half-lives for the italicized data were determined using methods that are dependent on half-live values of other isotopes. Half-lives for un-italicized values are based on direct thorium amount-versus-activity measurements.