A while back I posted on a GSI experiment that found electron capture in 142-Pr and 140-Pm followed a non-exponential decay law given by:
Two other groups have looked for this oscillating decay curve and haven’t found it. The GSI response seems to be the environment in a storage ring is different than what is found in the other experiments. If you embed the nuclei in a material you somehow restrict the phase space which changes how the nuclei decay. Or something.
Today I saw this weird paper that finds an oscillation in the decay of 32-Si and 226-Ra that correlates with the sun-earth distance. It is really weird when you consider their two examples; 32-Si decays by 
The authors state:
Although there are hundreds of potentially useful nuclides whose half-lives have been measured, the data from many of the experiments we examined were generally not useful, most often because data were not acquired continuously over sufficiently long time periods.
I’m not sure why they didn’t verify the 32-Si and 226-Ra examples before posting the paper. It would be easy to do and would make a good undergraduate project. Take a standard source such as 60-Co and/or 137-Cs and use a germanium or NaI detector to count the decays every other week for a year. One could do the same with a silicon detector and a standard 
Tags: physics
