Re: Half Life of Po-218 (Radium A)

[Duane Schmidt <DWS2@nrc.gov>]

John Takala asked about the half-life of Po-218:
>>>>>I was recently looking up decay information for radon progeny on the National
Nuclear Data Center's web program NuDat.  To my surprise it listed the half life of
Po-218 as 3.11 minutes.  

The value that I have commonly seen used is 3.05 minutes (e.g., Table of Isotopes -
7th edition, ICRP 38).  This is a change of nearly 2%! 

Does anyone have any comments on the revised half life of Po-218? What is the
reference for it?
<<<<<
John,

The last two editions of the Chart of the Nuclides, published by GE Nuclear Energy
(15th edition in 1996, 14th edition in 1989) list a value of 3.10 minutes, closer to the
higher values you mentioned. I also recall that several years ago a researcher at the
DOE's radon laboratory in Grand Junction, CO, was trying to measure the half-life
with increased precision. I can't recall the name right now, but Hal Langner (if he is
still there) at the lab probably would know.

Duane.

Duane W. Schmidt
U.S. Nuclear Regulatory Commission
NMSS/DWM/URB
mailto: dws2@nrc.gov