Primary standardization of 212Pb activity by liquid scintillation counting

Denis E Bergeron; Jeffrey T Cessna; Ryan P Fitzgerald; Lizbeth Laureano-Pérez; Leticia Pibida; Brian E Zimmerman

doi:10.1016/j.apradiso.2022.110473

Primary standardization of ²¹²Pb activity by liquid scintillation counting

Appl Radiat Isot. 2022 Dec:190:110473. doi: 10.1016/j.apradiso.2022.110473. Epub 2022 Sep 22.

Authors

Denis E Bergeron¹, Jeffrey T Cessna², Ryan P Fitzgerald², Lizbeth Laureano-Pérez², Leticia Pibida², Brian E Zimmerman²

Affiliations

¹ Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA. Electronic address: denis.bergeron@nist.gov.
² Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA.

Abstract

An activity standard for ²¹²Pb in equilibrium with its progeny was realized, based on triple-to-double coincidence ratio (TDCR) liquid scintillation (LS) counting. A Monte Carlo-based approach to estimating uncertainties due to nuclear decay data (branching ratios, beta endpoint energies, γ-ray energies, and conversion coefficients for ²¹²Pb and ²⁰⁸Tl) led to combined standard uncertainties ≤ 0.20 %. Confirmatory primary measurements were made by LS efficiency tracing with tritium and 4παβ(LS)-γ(NaI(Tl)) anticoincidence counting. The standard is discussed in relation to current approaches to ²¹²Pb activity calibration. In particular, potential biases encountered when using inappropriate radionuclide calibrator settings are discussed.

Keywords: Activity calibration; Anticoincidence counting; Decay chain; Dose calibrator; Efficiency tracing; Pb-212; Radionuclide calibrator; TDCR; Well counter.

Published by Elsevier Ltd.

MeSH terms

Lead*
Radioisotopes
Reference Standards
Scintillation Counting* / methods
Tritium / analysis

Substances

Lead
Radioisotopes
Tritium

Grants and funding

9999-NIST/Intramural NIST DOC/United States