Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

The Half-Life of 209Po : Revisited



Ronald Colle, Ryan P. Fitzgerald, Lizbeth Laureano-Perez


A substantial 25 % error in the then known and accepted (102  5) year half-life of 209Po was reported on in 2007. This error was detected from decay data from two separate primary standardizations of a 209Po solution standard, which were performed approximately 12 years apart. Despite author claims that this observation was not a new half-life determination, it was nevertheless included in subsequent nuclear data evaluations and compilations to obtain a currently tabulated value of (115  13) a, computed from the median and range of the two half-life reports. A third primary standardization on the identical 209Po solution has since been performed to derive a new half-life value of (125.2  3.3) a. This half-life determination was obtained from 30 distinct data sets over a period of 20.7 years, encompassing over 700 liquid scintillation measurements with nearly 50 counting sources all prepared from the same solution, and as obtained over a very broad range of measurement conditions (composition of cocktails, characteristics of counters, time sequencing) during five periods in 1993, 1994, 2005, and 2013.
Journal of Physics G-Nuclear and Particle Physics


209-polonium, half-life, liquid scintillation, measurment


Colle, R. , Fitzgerald, R. and Laureano-Perez, L. (2014), The Half-Life of 209Po : Revisited, Journal of Physics G-Nuclear and Particle Physics, [online], (Accessed April 24, 2024)
Created August 13, 2014, Updated November 10, 2018