Table 2 85Kr and 81Kr data for the validation measurements

From: 81Kr dating of 1 kg Antarctic ice

 

Discharge-excitation ATTA

Optical-excitation ATTA

 

With ~3 μL STP of krypton

With ~100 nL STP of krypton

 

85Kr

81Kr

85Kr

81Kr

 

dpm/cc

pMKr

dpm/cc

pMKr

Sample 1

<0.1

3.9 ± 0.4

<0.3

4.0 ± 0.7

Sample 2

1.70 ± 0.08

6.6 ± 0.4

1.21 ± 0.26

7.0 ± 0.9

Sample 3

3.63 ± 0.32

31.7 ± 1.3

3.24 ± 0.48

31.4 ± 2.5

Sample 4

1.17 ± 0.20

57.5 ± 2.1

1.06 ± 0.30

65.2 ± 3.7

Sample 5

3.30 ± 0.18

70.5 ± 2.3

2.81 ± 0.45

68.0 ± 3.7

Sample 6

0.18 ± 0.01

84.7 ± 2.6

0.47 ± 0.19

82.3 ± 3.9

Sample 7

<0.2

100.0 ± 3.0

<0.3

96.9 ± 4.4

  1. The validation measurements are plotted in Fig. 2 of the manuscript. The 85Kr abundance is provided in the units of dpm/cc (decay per minute per cubic centimeter STP of krypton). The 81Kr abundance is provided in the units of pMKr (percent Modern Krypton). The given errors are 1σ standard deviations, whereas upper limits are given at a 90% confidence level. The leak-corrected 81Kr abundances \(R^{\prime}_{81}\) (see text) are shown for the optical-excitation ATTA measurements.
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