Half-life evaluations for 3H, 90Sr, and 90Y.
A recent paper has reviewed methods for the evaluation of discrepant sets of data and demonstrated the results of applying these methods to the published half-life data of 90Sr and 137Cs [MacMahon, T.D., Pearce, A., Harris, P., 2004. Convergence of techniques for the evaluation of discrepant data. Appl. Radiat. Isot. 60, 275-281]. The half-life data for 3H has been subject to a comprehensive review and critical evaluation by Lucas and Unterweger [2000. Comprehensive review and critical evaluation of the half-life of tritium. J. Res. Natl. Inst. Stand. Technol. 105, 541-549]. The current paper reports the results of applying the various evaluation procedures of MacMahon et al. Convergence of techniques for the evaluation of discrepant data. Appl. Radiat. Isot. 60, 275-281] to the data of Lucas and Unterweger [Comprehensive review and critical evaluation of the half-life of tritium. J. Res. Natl. Inst. Stand. Technol. 105, 541-549], resulting in a recommended half-life of 4497(4) days. MacMahon et al. [Convergence of techniques for the evaluation of discrepant data. Appl. Radiat. Isot. 60, 275-281] highlighted problems in the evaluation of the discrepant half-life data of 90Sr, in particular the worrying upward trend in the data, where the weighted mean of all the measurements increases, on average, by 35 days each time a new measurement result is added. The current paper reports on further analyses of these data. New measurements of the half-life of 90Y have been reported by Kossert and Schrader [2004. Standardization by liquid scintillation counting and half-life measurements of 90Y. Appl. Radiat. Isot. 60, 741]. This has prompted a new evaluation of all available published 90Y half-life data. The data are fairly consistent, and a value of 64.063(16) h is recommended.
MacMahon
Desmond
D
National Physical Laboratory, Teddington, Middlesex TW11 0LW, UK. desmondmacm@yahoo.co.uk
D003198:Computer Simulation; D017408:Guidelines as Topic; D006207:Half-Life; D008956:Models, Chemical; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods*; D012015:Reference Standards; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013326:Strontium Radioisotopes / Q000032:analysis* / Q000737:chemistry / Q000592:standards; D014316:Tritium / Q000032:analysis* / Q000737:chemistry / Q000592:standards; D015021:Yttrium Radioisotopes / Q000032:analysis* / Q000737:chemistry / Q000592:standards
D013326:Strontium Radioisotopes; D015021:Yttrium Radioisotopes; D014316:Tritium