Half-life of radium-223

Direct measurement of the half-life of 223Ra

“…The half-life value determined in this work is in agreement with the other directly measured published values (which quote the most precise values) of Kirby et al (1965) and Kossert et al (2015). The remaining published values have all been performed by the fitting of composite decay curves to a single curve following the ingrowth of the decay progeny of 227 Ac and show a large variation in the determined half-lives.…”

“…As a consistency check the half-lives of both 227 Th and 223 Ra were determined from a fit of the data, with both half-lives as free parameters. By this method they determined half-lives for 227 Th and 223 Ra that were more than 1.5 standard uncertainties away from their reported half-life of 227 Th and 223 Ra determined by Kirby et al (1965). It should be considered that Jordan and Blanke (1967) did not propose this 223 Ra half-life as a half-life determination and is used only as a check of the values of 227 Th determined and thus has not been examined rigorously.…”

“…It should be considered that Jordan and Blanke (1967) did not propose this 223 Ra half-life as a half-life determination and is used only as a check of the values of 227 Th determined and thus has not been examined rigorously. This work was undertaken at the same establishment as the work of Kirby et al (1965) with Jordan as a co-author, thus it cannot be considered as an independent value. In the evaluation procedure of the Decay Data Evaluation Project (DDEP) it is required that only one value can be taken from any one institute, with the latest publication superseding earlier work (Bé et al, 1999).…”

“…The remaining published values have all been performed by the fitting of composite decay curves to a single curve following the ingrowth of the decay progeny of 227 Ac and show a large variation in the determined half-lives. (1967) The value determined by Jordan and Blanke (1967) is based on the fit of 227 Th and 223 Ra ingrowth from 227 Ac, in the publication Jordan and Blanke (1967) use the half-life of 223 Ra determined by Kirby et al (1965) to determine a half-life for 227 Th. As a consistency check the half-lives of both 227 Th and 223 Ra were determined from a fit of the data, with both half-lives as free parameters.…”

“…A review of the currently published measurements of 223 Ra, summarised in Table 1, highlighted a paucity of consistent data, with only three independent values (Kossert et al, 2015;Miller et al, 1987;Robert, 1959), while three more values were published by a single laboratory (Hagee et al, 1954;Jordan and Blanke, 1967;Kirby et al, 1965). Two of these values have been derived by direct measurements of the 223 Ra radioactive decay half-life (Kirby et al, 1965;Kossert et al, 2015). The remaining measurements were performed by abstracting the half-life by free fitting of composite decay curves to time-series measurements of 223 Ra or 227 Ac/ 227 Th and 223 Ra plus decay progeny (Hagee et al, 1954;Jordan and Blanke, 1967;Miller et al, 1987;Robert, 1959).…”