title: Decay/ingrowth uncertainty correction of (210)Po/(210)Pb in seawater.
abstract: Due to increasing application of (210)Po/(210)Pb in studying particle dynamics, a consistent procedure and calculation to derive accurate and precise result of (210)Po and (210)Pb in seawater should be proposed in the framework of intercalibration by GEOTRACES. The associated uncertainty of radioactivity, which is a significant component of data report, plays a vital role in intercomparison and should be well evaluated. Although measurement uncertainty of laboratory result was well defined in ISO standards and IAEA technical documents, the decay/ingrowth uncertainty correction from laboratory result to in-situ result was less studied. It was demonstrated that the relative uncertainty of in-situ (210)Pb activity was independent of elapsed time and equal to relative uncertainty of laboratory measuring (210)Po activity at second spontaneous deposition date. The relative uncertainty of in-situ (210)Po activity decreases with in-situ activity ratio of (210)Po to (210)Pb and increases with elapsed time between sampling date and separation date, relative uncertainty of laboratory measuring (210)Po activity at first spontaneous deposition date and relative uncertainty of in-situ (210)Pb activity. It was more important to improve precision of (210)Po at first spontaneous deposition date than that of (210)Po at second spontaneous deposition date. To obtain a desirable relative uncertainty of in-situ (210)Po activity, the maximum allowing elapsed time for (210)Po, which was important for sampling strategy making and quality assurance, was calculated by in-situ activity ratio of (210)Po to (210)Pb and precision of analytical method for (210)Po. The methodology of decay/ingrowth uncertainty correction could also be applied for other radionuclide pairs ((234)Th/(238)U, (90)Y/(90)Sr, (210)Bi/(210)Pb), sample matrixes (aerosols), and disciplines.
authors.affiliation: Department of Engineering Physics, Tsinghua University, Beijing 100084, China; Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education, Beijing 100084, China; Lab of Marine Isotopic Technology and Environmental Risk Assessment, State Oceanic Administration, Xiamen 361005, China; Key Lab of Global Change and Marine-Atmospheric Chemistry, State Oceanic Administration, Xiamen 361005, China; Third Institution of Oceanography, State Oceanic Administration, Xiamen 361005, China.
authors.forename: Wuhui
authors.initials: W
authors.lastname: Lin
authors.affiliation: Department of Engineering Physics, Tsinghua University, Beijing 100084, China; Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education, Beijing 100084, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Ma
authors.affiliation: Key Lab of Global Change and Marine-Atmospheric Chemistry, State Oceanic Administration, Xiamen 361005, China; Third Institution of Oceanography, State Oceanic Administration, Xiamen 361005, China. Electronic address: Lqchen@soa.gov.cn.
authors.forename: Liqi
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Engineering Physics, Tsinghua University, Beijing 100084, China; Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education, Beijing 100084, China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Zeng
authors.affiliation: Lab of Marine Isotopic Technology and Environmental Risk Assessment, State Oceanic Administration, Xiamen 361005, China; Third Institution of Oceanography, State Oceanic Administration, Xiamen 361005, China.
authors.forename: Jianhua
authors.initials: J
authors.lastname: He
authors.affiliation: Department of Engineering Physics, Tsinghua University, Beijing 100084, China; Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education, Beijing 100084, China.
authors.forename: Shi
authors.initials: S
authors.lastname: Zeng
mesh_terms: D007856:Lead Radioisotopes / Q000032:analysis*; D008962:Models, Theoretical; D011059:Polonium / Q000032:analysis*; D011834:Radiation Monitoring / Q000379:methods*; D011851:Radioactivity; D012623:Seawater / Q000032:analysis*; D035501:Uncertainty
chemical_list: D007856:Lead Radioisotopes; D011059:Polonium
keywords: (210)Pb; (210)Po; GEOTRACERS; Radioactivity; Seawater; Uncertainty