RESUMO
RATIONALE: The measurement of (210) Pb provides an assessment of the risk an individual faces of developing lung cancer as a result of their exposure to radon and radon decay products. Existing radiometric techniques are not sensitive enough to detect (210) Pb in many exposures. This report describes the further development of a method of measuring (210) Pb using Accelerator Mass Spectrometry (AMS). METHODS: (204,205,208,) (210) Pb measurements were performed by AMS. Samples were prepared from stock solutions of (204) Pb, (205) Pb, (208) Pb and (210) Pb and measured by making PbF3 (-) ions at the IsoTrace AMS facility using a SIMS-type Cs(+) sputter source. Potential interferences in Pb(3) (+) isotope measurement and the overall efficiency of Pb beam production were determined experimentally. RESULTS: (204) Pb and (205) Pb suffer from molecular and atomic isobaric interferences that cannot be removed without sacrificing the efficiency of (210) Pb measurements whereas (208) Pb suffers from no interferences. The abundance sensitivity of (210) Pb/(208) Pb was 1.3 × 10(-12) . Keeping the (210) Pb/(208) Pb spike below this level resulted in a detection limit of 4.4 mBq of (210) Pb using the IsoTrace AMS facility. CONCLUSIONS: This study identified key interferences in the measurement of PbF3 (-) â Pb(3) (+) ions and demonstrated a new AMS method to measure (210) Pb. This new AMS technique is about five times more sensitive than gamma and beta spectroscopy measurements of (210) Pb and the measurement time is much shorter. Copyright © 2016 John Wiley & Sons, Ltd.
