Table 1.

${}^{222}$Rn emanation measurements of grade-1 titanium samples. The normalization to surface area and, where relevant, to weld seam length is also given. For comparison the ${}^{226}$Ra bulk activity taken from [10] is quoted and referred to as RID (Radioassay-ID) defined there

ID	Sample	Supplier	Description	Treatment	${}^{222}$Rn emanation rate	${}^{226}$Ra activity [10]
#1	Ti grade-1	Supra Alloys	14 plates 20.3 cm $\times$ 20.3 cm $\times$ 0.25 cm Total: 1.2 m${}^2$/6.9 kg	Untreated	(120 ± 30) $\mathrm{\mu }$Bq (101 ± 28) $\mathrm{\mu }$Bq/m${}^2$	RID #40 $<0.6$ mBq/kg
#1a			Same as sample #1	Etched for 2 h in 1.8% HNO${}_3$	(160 ± 50) $\mathrm{\mu }$Bq (140 ± 40) $\mathrm{\mu }$Bq/m${}^2$
#2	Ti grade-1	Nironit	13 plates 20 cm$\times$20 cm$\times$0.2 cm Total: 1.1 m${}^2$/4.6 kg 17.4 m of TIG-weld seam	Untreated	(540 ± 60) $\mathrm{\mu }$Bq (510 ± 5) $\mathrm{\mu }$Bq/m${}^2$ (31 ± 3) $\mathrm{\mu }$Bq/m	RID #39 $<1.3$ mBq/kg
#2a			7 plates of sample #2 Total: 0.6 m${}^2$/2.4 kg 9.4 m of TIG-weld seam	Etched for 2 h in 0.6% HF/7.6% HNO${}_3$ (“pickling”)	(73 ± 28) $\mathrm{\mu }$Bq (130 ± 50) $\mathrm{\mu }$Bq/m${}^2$ (7.8 ± 2.9) $\mathrm{\mu }$Bq/m
#3	Ti grade-1	Nironit	13 plates 20 cm$\times$20 cm$\times$0.2 cm Total: 1.1 m${}^2$/4.6 kg	Untreated	(2980 ± 200) $\mathrm{\mu }$Bq (2810 ± 190) $\mathrm{\mu }$Bq/m${}^2$	RID #38 ($1.1\pm 0.4$) mBq/kg
#3a			6 plates of sample #3 Total: 0.5 m${}^2$/2.1 kg	Electropolished 30 $\mathrm{\mu }$m surface removed	$<39$ $\mathrm{\mu }$Bq $<80$ $\mathrm{\mu }$Bq/m${}^2$