Use of Concise Notation for Half-life Uncertainties

November 28th, 2018
by Joseph Magill

The use of the concise notation is best demonstrated with an example. Research papers often publish half-lives in so-called ‘non-concise’ form. As an example, the half-life of the alpha emitter Gd-148 has been measured to be T1/2= 70.9 ± 1.0y. When this information is published in, for example, ENSDF, NDS etc. a more concise notation is used as shown in the diagram below for Gd-148 i.e. T1/2(y) = 70.9 10 where it understood that the number in italics is the numerical value of the standard uncertainty referred to the corresponding last digits of the quoted result.
Gd148 Extract from ENSDF for nuclear data on Gd-148.

As another example, the half-life of Po-209 is given in the original scientific paper as as T1/2(y) = (125.2 ± 3.3) a. In Nucleonica’s Nuclide Datasheets, however, the half-life is given as T1/2(y) = 125.2 (33) a. Notice the notation follows that of NIST which is slightly different from the ENSDF above (NIST has the uncertainty in brackets, non-italic e.g. (33); ENSDF has the uncertainty in italic withour brackets e.g. 33). Further examples of uncertainties notations are shown below.
NDS-Uncertainties For further information see the references below.

References
Use of concise notation for data uncertainties
Standard Uncertainty and Relative Standard Uncertainty
ENSDF manuel; Note on uncertainties is on page 104
NDS Notes on page 7

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