Per Roos, Nikola Markovic, Sven Nielsen

A comparison of methodologies in analyzing 210Pb-210Bi-210Po

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Pb-210Bi-210Po-210

Ingrowth of 210Bi and 210Po from 210Pb

How to do? What way to go?

Gamma spectrometry of 210Pb 46 keV (4%)

• ”Large” (~15g) samples on single Ge-detector.

• Small (0-4g) samples in anti-compton shielded well-Ge

Gamma Counting

Low-level gamma spectrometry for the determination of 210PbMarkovic et.al. JRNC, 311 (2017), 1473-1478

210Po by LSC?209Po

209+210Po

Co-adsorption of 210Pb and 210BiDiscs for solid-state alpha spec?

Aspects on the analysis of 210PoHenricsson et.al. JER 102, (2011), 415-419.

Beta Counting

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Col. volumes

Retention of selected metals on Sr-Resin

BaFeLaSrPbBi

2M HCl 6M HNO3 6M HCl

Sr-Resin chosen for isolation of 210Pb

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U & Th on Sr-Resin

232Th

238U

2M HCl 6M HNO3 6M HCl

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BaFeLaSrPbBi

Retention of selected metals on AG1x4

1M HCl 8M HCl 0.5M HNO3

Anion exchange using AG1x4 used for 210Bi

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U & Th on AG1x4

232Th

238U

1M HCl 8M HCl 0.5M HNO3

Stable lead

• + No stress.• - Potential conflict with Pb-scientists (severe memory effects in ICP-MS)• - Risk of 210Pb in stable lead standard (typical < 1Bq/g of lead so minor problem)

212Pb (10.6h half-life). Extracted from aged 232Th, ‘hot’ 228Ra-samples (eg- scale from oil-platforms) or aged

232U.• 232Th-salts have the disadvantage of sometimes containing 230Th (and trace 210Pb).• 228Th isolation and 224Ra ingrowth required for 228Ra-samples to remove 226Ra-

210Pb.• Following isolation of 228Th by anion exchange the eluted 224Ra (8M HNO3) is

converted to 0.2M HCl and adsorbed onto Dowex 50Wx8. • Elution of 212Pb using 1M HCl.

Choice of tracers

210Pb with 212Pb astracer.

210Pb-210Bi-210Po

212Pb-212Bi-212Po-208Tl

210Bi by stable Bias tracer.

Conclusion

210Pb analysed using gamma spectrometry or LSC using stable Pb or 212Pb as tracer.

210Bi analysed using LSC with stable Bi as tracer.

210Po analysed by solid state alpha spectrometry.

A comparison of methodologies in analyzing 210Pb-210Bi-210Po �Slide Number 2Slide Number 3Slide Number 4Slide Number 5Slide Number 6Slide Number 7Slide Number 8Slide Number 9Slide Number 10Slide Number 11Slide Number 12Slide Number 13Slide Number 14Slide Number 15