Critically evaluated half-life for {sup 222}Rn radioactive decay and associated uncertainties
- National Institute of Standards and Technology, Gaithersburg, MD (United States)
A critical review and evaluation of 17 independent determinations of the half-life for {sup 222}Rn decay made over the past 90 years (c. 1902-1994) indicates that a five-significant figure value of the half-life with a relative uncertainty of approximately 10{sup -4} is justified, but not for the reasoning usually invoked. Although the commonly adopted and tabulated high-precision value of T = 3.8235 {+-} 0.0003 d, which is based almost exclusively on the 1972 measurements of Butt and Wilson, is consistent and virtually indistinct; a value of T = 3.8232 {+-} 0.0004 d, obtained by considering the entire available data base, is more supportable. Even in the extreme of a very conservative evaluation, the half-life is certainly known to a relative uncertainty interval of {+-}0.03 percent which contradicts some other extant data compilations that contend that no adopted half-life value for any radionuclide has a relative uncertainty of less than {+-}0.1 percent. Resulting propagated uncertainty contributions for either {sup 222}Rn radioactive decay or {sup 222}Rn growth accumulations from {sup 226}Ra decay due to the uncertainty in the {sup 222}Rn half-life is thereby clearly negligible in nearly all {sup 222}Rn measurement applications.
- OSTI ID:
- 160344
- Journal Information:
- Radioactivity and Radiochemistry, Journal Name: Radioactivity and Radiochemistry Journal Issue: 1 Vol. 6; ISSN 1045-845X; ISSN RARAE6
- Country of Publication:
- United States
- Language:
- English
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