- #1
henrym_
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Hi there, not sure whether this is in the right section but:
I've made two runs of a radioactive decay experiment where I've got a log(N) vs. time plots. From this I've got the decay constants and hence the half-life. I've averaged these two half-lives ( = 160 secs) and now I'm trying to work out the error associated with the half-life.
Usually I'd take the error on the fits of the two graphs and then use the error propagation equations to get the error ( = 2 secs) but I've been advised to use Poisson statistics as the error I have is likely to be an underestimate (which I agree with).
I've done some research and I've read that the standard deviation (i.e. the error) for a Poisson distribution is the square root of the mean. Does that mean I square root the two individual half-lives to get the error? (Giving me an error of approx. 16 secs)
If not, can anybody lend me help? How do I work out the final error on the half-life using Poisson statistics?
Some of the sites I've used:
https://www.colorado.edu/physics/phys2170/phys2170_fa06/downloads/poisson.pdf
https://www.phys.ufl.edu/courses/phy4803L/group_I/gamma_spec/poisson.pdf
https://ned.ipac.caltech.edu/level5/Leo/Stats2_2.html
https://www.colorado.edu/physics/phys2150/phys2150_sp14/phys2150_lec6.pdf
Thanks :)
I've made two runs of a radioactive decay experiment where I've got a log(N) vs. time plots. From this I've got the decay constants and hence the half-life. I've averaged these two half-lives ( = 160 secs) and now I'm trying to work out the error associated with the half-life.
Usually I'd take the error on the fits of the two graphs and then use the error propagation equations to get the error ( = 2 secs) but I've been advised to use Poisson statistics as the error I have is likely to be an underestimate (which I agree with).
I've done some research and I've read that the standard deviation (i.e. the error) for a Poisson distribution is the square root of the mean. Does that mean I square root the two individual half-lives to get the error? (Giving me an error of approx. 16 secs)
If not, can anybody lend me help? How do I work out the final error on the half-life using Poisson statistics?
Some of the sites I've used:
https://www.colorado.edu/physics/phys2170/phys2170_fa06/downloads/poisson.pdf
https://www.phys.ufl.edu/courses/phy4803L/group_I/gamma_spec/poisson.pdf
https://ned.ipac.caltech.edu/level5/Leo/Stats2_2.html
https://www.colorado.edu/physics/phys2150/phys2150_sp14/phys2150_lec6.pdf
Thanks :)