Table 2.

Measured massic activity and calculated molality of ²³³Pa in the S solution, measured massic activity of ²³¹Pa in the M solutions, and calculated molality of ²³¹Pa in the RM solution

Analysis laboratory	Analysis method	S solution 233Pa massic activity (Bq g−1)	S solution molality of 233Pa (pmol g−1)
NIST	LTAC*	26,320 ± 170	0.1470 ± 0.0010
NIST	HPGe γ spectrometry	26,120 ± 570	0.1459 ± 0.0032
NRC	LTAC*	26,190 ± 370	0.1463 ± 0.0021
NRC	Coincidence counting	26,340 ± 450	0.1471 ± 0.0025
NRC	TDCR	26,310 ± 220	0.1469 ± 0.0012
NRC	CNET 1	26,040 ± 230	0.1454 ± 0.0013
NRC	CNET 2	26,130 ± 250	0.1459 ± 0.0014
NPL	Coincidence counting*	26,340 ± 180	0.1471 ± 0.0010
Analysis laboratory	Analysis method	M solution 231Pa massic activity (Bq g−1)	RM solution molality of 231Pa (pmol g−1)
NIST	α Spectrometry*	2096 ± 68	27.6 ± 1.0
NIST	CNET Corrected	2154 ± 67	28.41 ± 0.73
NIST	CNET	2175 ± 67	28.7 ± 1.0
NRC	CNET*	2193 ± 66	28.92 ± 0.98
NRC	TDCR	2266±41	29.88 ± 0.72

Molality of ²³³Pa was converted from massic activity using the evaluated ²³³Pa half-life [12] of (26.98 ± 0.2) days (k = 1). The molality of ²³¹Pa in the RM solution was calculated from the M solution massic activity using the dilution factor of 187.279 ± 0.047 (k = 2) and the evaluated ²³¹Pa half-life [11] of (32 670 ± 260) a (k = 1). All values are decay corrected to a reference time of 27 June 2017 22:50 UTC. Uncertainties are expanded uncertainties (U=k u_c) with a coverage factor (k) of 2. NIST massic activity values are from [13] for ²³³Pa and [15] for ²³¹Pa. All massic activity values for NRC are from [14] and the cited ²³³Pa activity value from NPL is from Keightley (personal communication, 7 February 2018). CNET 1 and 2 refer to analyses performed on liquid scintillation counters from different manufacturers

^*Primary or highest confidence activity measurements, as designated by the analysis laboratories