2006 Volume 55 Issue 8 Pages 469-472
We assessed usefulness of commercially available sealed 22Na positron sources for positron annihilation lifetime measurements. Three sources with different nominal activities below 1.85 MBq were adopted for measuring positron annihilation lifetimes in silicon and annealed copper. It was found that all the sources have long lifetime components over 1 ns with different relative intensities of several percents. The result suggests that care should be taken in the analysis of the positron annihilation lifetime data obtained with these sources.