Hi, As I said in my post, I was assuming a linear relationship. I should add that I completely agree with everything that Matt has said. I also find it a little odd that you don't already get the data in energy from the monochromator or from the software used to run it. You need that time-energy relationship and the details of how the scan is made and can not simply make an assumption. It is possible to do many things to your data as I demonstrated but it is not necessarily the correct thing to do. cheers, Adam Matt Newville wrote:
Syed, Adam,
I think the suggestion from Adam and one of the suggestions from Anatoly assume the energy linear in time. Is that the really case? For quick-scanning modes, many beamlines run the mono at a constant angular velocity, so that time maps linearly to angle, which then needs to be converted (non-linearly) to energy. Then again, some quick-scanning beamlines use a special cam drive, in which neither angle nor energy would be linear in time.
Again, you need know these details in order to correctly assign energies to the data. None of it is particularly difficult, so there's no point in guessing, and stretching or massaging the energy scale until two energy points correct does not mean the rest are correct. You need to find out from the beamline how the data mapped onto energy and fix that. While you can probably use Ifeffit macros within Athena to do this correction, this is really a job for the beamline, not for Athena. Having an option in Athena that allowed the user to say "I don't know why my energy scale is bad, but can you please stretch the energies so that these two energies are what I'd like them to be" is a horrible idea.
--Matt _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
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