[Ifeffit] Sorry

Bruce Ravel bravel at bnl.gov
Thu Jul 23 15:16:34 CDT 2009


On Wednesday 22 July 2009 09:27:16 pm Richard Mayes wrote:
> In cases where intense pre-edge features are observed, such as the one you
> attached, you should manually set the Eo and not accept the Athena
> defaults.  I usually start with half-way up the absorption edge (you can
> look at the derivative and move the Eo value to the maximum in the
> derivative; however, make sure you don't move it back to the pre-edge).


I want to expand on one part of Richard's excellent advice.  The
default values in Athena are not selected by algorithms that are
particularly sophisticated and they are certainly not chosen to be
appropriate to a specific data set in any except the most facile
manner.  Athena is surprisingly good at not sucking at picking default
values, but you should most certainly not trust the defaults blindly.
She regularly chooses inappropriate values for E0, normalization, and
background removal that a human operator would not choose.  So feel
free to poke at all those numbers on the left side of the Athena
window -- that's what they are there for ;-)

B


-- 

 Bruce Ravel  ------------------------------------ bravel at bnl.gov

 National Institute of Standards and Technology
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