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Guidelines and Limits for the Quantification of Ra Isotopes and Related Radionuclides With the Radium Delayed Coincidence Counter (RaDeCC)
Author(s) -
DiegoFeliu M.,
Rodellas V.,
AlordaKleinglass A.,
Tamborski J.,
Beek P.,
Heins L.,
Bruach J. M.,
Arnold R.,
GarciaOrellana J.
Publication year - 2020
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1029/2019jc015544
Subject(s) - radium , coincidence , radionuclide , isotope , radiochemistry , nuclear medicine , environmental science , chemistry , physics , nuclear physics , medicine , pathology , alternative medicine
The Radium Delayed Coincidence Counter (RaDeCC) is one of the most extensively used equipment for measuring 223 Ra and 224 Ra activities in water and sediment samples. Samples are placed in a closed He‐circulation system that carries the Rn produced by the decay of Ra to a scintillation cell. Each alpha decay recorded in the cell is routed to an electronic delayed coincidence system which enables the discrimination of 223 Ra and 224 Ra. In this study, the measurement and quantification methods using the RaDeCC system are assessed through analyses of registered data in different RaDeCC systems worldwide and a set of simulations. Results of this work indicate that the equations used to correct for 223 Ra and 224 Ra cross‐talk interferences are only valid for a given range of activities and ratios between isotopes. Above certain limits that are specified in this study, these corrections may significantly overestimate the quantification of 223 Ra and 224 Ra activities (up to ~40% and 30%, respectively), as well as the quantification of their parents 227 Ac and 228 Th. High activities of 226 Ra may also produce an overestimation of 224 Ra activities due to the buildup of 222 Rn, especially when long measurements with low activities of 224 Ra are performed. An improved method to quantify 226 Ra activities from the buildup of 222 Rn with the RaDeCC system is also developed in this study. Wethus provide a new set of guidelines for the appropriate quantification of 223 Ra, 224 Ra, 227 Ac, 228 Th, and 226 Ra with the RaDeCC system.